课程文献中心 更多>>

摘要： A design is called t-pyramidal when it has an automorphism group which fixes t points and acts sharply transitively on the remaining points. We determine all symmetric $(2^k-1,2^{k-1},2^{k-2})$-designs which are $(2^{k-1}-1)$-pyramidal over abelian groups.

关键词： Highland red rice resistant starch   Antidiabetic   Gut microbiota-PYY/GLP-1 pathway  

摘要： Highland red rice from southwestern China is recognized as a health-promoting grain,but its potential in dia-betes management remains *** this study,resistant starch(RS)and pigment extracts(RP)were isolated from highland red rice to determine whether they act in combination to modulate gut microbiota and metabolism in streptozotocin(STZ)-induced diabetic mice,with the aim of elucidating the mechanisms under-lying their anti-hyperglycemic *** RS nor RP single interventions significantly improved key gly-cemic parameters;however,the combined intervention(RSP)significantly reduced fasting blood glucose(FBG)levels and improved glucose tolerance.16S rRNA analysis indicated RSP intervention increased the abundance of short-chain fatty acid(SCFA)-producing bacteria,including Lactobacillus,Lactococcus,Akkermansia,and Rom-boutsia,while decreasing pro-inflammatory taxa such as Candidatus_*** analysis revealed RSP intervention elevated levels of cholic acid(CA),hyocholic acid(HCA),and sphingolipid metabolism in-termediates(sphingosine and sphinganine).Crucially,both SCFA concentrations and the expression of peptide YY(PYY)and glucagon-like peptide-1(GLP-1)were significantly elevated after RSP *** findings demonstrate that RS and RP together exert combined anti-hyperglycemic effects by modulating gut microbiota and its metabolites,thereby activating the PYY/GLP-1 *** highlights the therapeutic potential of highland red rice components in diabetes management.

关键词： Angiogenesis   Collagen–chitosan scaffold   Deferoxamine   Diabetic wound healing   HIF-1α stabilization   Oxidative stress   Tissue regeneration  

摘要： Diabetic wounds are characterized by impaired angiogenesis, prolonged inflammation, and delayed tissue regeneration, which often result in chronic non-healing ulcers. Hypoxia-inducible factor-1 alpha (HIF-1α) signaling plays a critical role in coordinating angiogenesis and tissue repair; however, its activity is markedly suppressed in diabetic conditions. This study aimed to evaluate the therapeutic efficacy of a collagen–chitosan sponge scaffold (CoChSS) loaded with deferoxamine (DFO) in enhancing diabetic wound healing through modulation of the hypoxic microenvironment and activation of angiogenic pathways. Type 2 diabetic rats were randomly assigned to three groups: untreated control, CoChSS scaffold alone, and DFO-loaded CoChSS (CoChSS/DFO). Full-thickness excisional wounds were created, and healing outcomes were evaluated on days 4 and 8 post-injury. Wound closure rate, mechanical properties, stereological parameters (fibroblast density, blood vessel density, and inflammatory cell infiltration), collagen deposition, gene expression (HIF-1α and SDF-1α, VEGF, TGF-β, TNF-α, IL-1β), and oxidative stress markers (CAT, SOD, GSH, and MDA) were systematically assessed. The CoChSS/DFO group exhibited significantly accelerated wound closure compared with both control and scaffold-only groups (P < 0.05). Mechanical testing demonstrated enhanced tensile strength and energy absorption in regenerated tissue following CoChSS/DFO treatment (P < 0.05). Stereological analysis revealed markedly increased angiogenesis and fibroblast proliferation, accompanied by a significant reduction in inflammatory cell infiltration (P < 0.05). Histological evaluation using Masson’s trichrome staining showed enhanced collagen deposition and improved matrix organization in the CoChSS/DFO group (P < 0.05). At the molecular level, CoChSS/DFO significantly upregulated HIF-1α, SDF-1α, VEGF, and TGF-β expression, while suppressing pro-inflammatory cytokines TNF-α and IL-1β (P < 0.05).

关键词： Compressed sensing   Analysis sparsity   Weighted ℓ1 analysis   Statistical dimension   Prior distributions  

摘要： Recovering signals that are sparse in a transform domain–so-called analysis-sparse vectors–from undersampled measurements is a fundamental problem in compressed sensing. In many practical scenarios, such as imaging, geophysics, and communications, the distribution of transform coefficients is known in advance, providing valuable prior information. Weighted ℓ₁ analysis offers a natural framework to exploit this knowledge, yet a principled method for choosing the weights has remained unsolved. In this work, we propose a distribution-aware framework for weight design. Using convex geometric tools, we establish a computable and nearly tight upper bound on the expected number of Gaussian measurements needed for exact recovery. This bound depends only on two accessible summaries of the prior in the analysis domain: marginal support probabilities and expected signs. Minimizing it yields a near-optimal weight vector that is stable, scale-invariant, and applicable a priori, without iterative tuning. Our theory accurately predicts recovery thresholds and shows how prior knowledge can be converted into provable measurement savings. Extensive simulations confirm substantial reductions in the number of required measurements and reconstruction error relative to unweighted ℓ₁ analysis, with the largest improvements observed for coherent and redundant operators. Overall, this work establishes a rigorous and practical recipe for leveraging distributional priors in analysis-based compressed sensing.

关键词： Density functional theory   Flame retardant materials   Ionic liquids   Magnesium hydroxide nanoparticles  

摘要： In response to the growing demand for environmentally friendly and efficient flame retardants, nano-magnesium hydroxide (nano-MH) has emerged as a promising candidate due to its high thermal stability and smoke suppression properties. However, its practical application is limited by agglomeration and high loading requirements.

摘要： Reliable assessment of lunar surface excavation, mobility, and in-situ resource utilization (ISRU) relies on mechanical properties of lunar regolith simulants, which differ substantially in particle morphology and gradation. However, systematic comparative studies on the morphology-mechanical behavior of commonly used simulants remain limited. This study presents a comparative investigation of three representative lunar regolith simulants, LHS-1, LMS-1, and LSP-2, using high-resolution micro-computed tomography (μCT) reconstruction and laboratory direct shear tests. Trainable Weka Segmentation (TWS) and level-set segmentation techniques were used to reconstruct the three-dimensional geometries of the particles, and multiscale shape descriptors were employed to quantify particle morphology. Principal component analysis and Mahalanobis distance evaluation revealed partially overlapping but statistically distinguishable morphological regions among the three simulants. The volume-weighted particle size distribution derived from the reconstructed particle reproduced the relative grading trend obtained from laboratory tests. Direct shear tests were conducted under normal stresses of 24, 48, and 96 kPa, with additional replicate tests used to assess repeatability and uncertainty. The Mohr-Coulomb analysis shows that LSP-2 exhibits the highest internal friction angle, followed by LMS-1 and LHS-1. Semi-quantitative analysis further indicates that the observed differences in shear strength are more reasonably interpreted when particle morphology and gradation are considered together, rather than by morphology alone. These results provide experimental support for numerical modeling and engineering design in future lunar surface operations.

关键词： Coconut water   Ergogenic   Radical scavenging   Multivariate data analysis   Metabolites  

摘要： The lyophilisation process helps to eliminate water,while retaining the bioactive compounds,and keeping co-conut water(CW)in a more suitable form for commercialisation ***,little is known about the difference between the biological and chemical profiles in the lyophilised form of ***,the variances across key Malaysian cultivars make it difficult to find high-value bioactive *** of comparable chemical and functional data hinders the development of lyophilised coconut water(LCW)as a standardised,commercially viable nutraceutical and functional food ***,this research aimed to characterise metabolite differences and volatile compounds in the LCW from four popular coconut cultivars in *** metabolites were detected using proton nuclear magnetic resonance(^(1)H NMR)combined with multivariate data analysis(MVDA)to correlate with their functional *** findings indicated that Malayan Yellow Dwarf(MYD)exhibited the highest levels of radical scavenging activities and in vitro anti-aging *** partial least squares(PLS)biplot revealed the presence of potent metabolites in MYD,such as epicatechin,valine,methionine,ascorbic acid,glycine,and catechin,which showed the highest correlation with the antioxidant and anti-aging *** characterisation results using HS-SPME-GC-MS showed that the volatile compounds in the LCW were grouped into esters,alkanes,alcohols,ketones,aldehydes,isocyanate,carboxylic acids,and *** summarise,it can be inferred that LCW from the MYD cultivar has the potential to serve as a valuable natural ergogenic ingredient,with free radical scavenging and in vitro anti-aging properties,which holds promise for future advancements in the preparation of health product ingredients.

关键词： 1/f noise suppression   Differential measurement system   Dual-channel thermistor correlation coefficient   Temperature stability   TianQin satellite  

摘要： The TianQin mission is designed to detect space gravitational waves in the ultra-low-frequency (ULF) band, ranging from 10⁻⁴ Hz to 1 Hz, through the deployment of three satellites into geocentric orbit. During in-orbit operation, the satellite's laser interferometric system encounters a significant challenge: the excessive 1/f noise from thermistors in the temperature measurement system compromises the precise measurement of temperature fluctuations at the interferometer. This study presents a dual-channel differential measurement system, integrating a three-layer noise isolation structure into the second channel. The simulations demonstrate the effectiveness and feasibility of the proposed system. For the first time, a correlation coefficient model for dual-channel thermistors is developed, the key mechanisms governing the dual-channel thermistor correlation coefficient are elucidated, facilitating the suppression of thermistor 1/f noise in the ULF range within the temperature measurement system and enabling precise characterization of temperature noise in the onboard laser interferometric system. Finally, the proposed dual-channel differential method structure and model undergo simulation and optimization analysis, the results show that for the Betatherm 10K3A1A NTC thermistor at a reference temperature of 298.15 K, the dual-channel thermistor correlation coefficient reaches a maximum value of 0.9995. The maximum residual 1/f noise after differential processing is 56.11 μΩ·Hz^-0.5, compared to the single thermistor's maximum 1/f noise level of 1643 μΩ·Hz^-0.5, resulting in a noise suppression rate of 96.59%. This method is anticipated to improve the temperature stability of the laser interferometric system aboard the TianQin satellite.

关键词： DFT   Dual fluorescence   ESIPT   Hydrogen bonds   Molecular structure   Tautomerism  

摘要： 3,5-Bis(2-hydroxyphenyl)-1H-1,2,4-triazole (bis-HPTA) undergoes a self-assisted proton transfer trigged proton transfer (PTTPT) in the excited state. The effect of replacement of triazole ring with oxadiazole was investigated by synthesizing 2,2′-(1,2,4-oxadiazole-3,5-diyl)diphenol (HPOD) and its methoxy derivative 2-(3-(2-methoxyphenyl)-1,2,4-oxadiazol-5-yl)phenol (MPOD). Density functional theory (DFT) and time dependent DFT calculations were also done to validate the experimental results. Single crystal analysis revealed the planar structure of HPOD and presence of hydrogen bonds between the proton donor and proton acceptor in both the units, (labeled as α- and β-rings). The hydrogen bonded oxadiazole nitrogen of α-ring is attached to the carbon atoms and that of β-ring is attached to oxygen atom and carbon atom. Despite the existence of intramolecular hydrogen bonds in both units, excited state intramolecular proton transfer (ESIPT) occurs in the α-ring (ESIPT-I) only, and no ESIPT occurs in the β-ring (ESIPT-II). In nonpolar solvent, cyclohexane, only tautomer emission is observed, whereas in other investigated solvents, HPOD emits dual emission, normal and tautomer emission. In solvents such as dimethylformamide and methanol, an additional anion is also detected. Time resolved and theoretical studies also supported these observations. The methoxy derivative also undergoes ESIPT. However, the breaking of β-ring (by replacing the hydroxy with a methoxy group), reduced the ESIPT along α-ring also. Theoretically simulated vibrational spectra also suggest that the proton transfer is favoured in the α-ring of HPOD rather than β-ring. In conclusion the substitution of more electronegative oxygen decreased the tendency of ESIPT in HPOD.

关键词： Glutaredoxin 1   Renal cell carcinoma   Sorafenib resistance   Ferroptosis   Bioinformatics  

摘要： Sorafenib resistance has limited the therapeutic efficacy in advanced renal cell carcinoma (RCC). Glutaredoxin 1 (GRX1, also known as GLRX), a redox-regulating oxidoreductase belonging to the thioredoxin superfamily, may mediate this resistance through ferroptosis suppression, but the underlying mechanisms remain incompletely understood.