查找使用阿拉丁产品的科研文献

The effect of carboxymethylation on the macromolecular conformation of the (1 → 3)-β -D-glucan of curdlan in water

Zhixiang Cai,Hongbin Zhang

The chain conformational change in curdlan during carboxymethylation was investigated using nuclear magnetic resonance (NMR), circular dichroism (CD) spectroscopy, and atomic force microscopy (AFM). The distributions of carboxymethyl substituents within anhydroglucose unit (AGU) of CMCD were found to follow the order of OH (6) > OH (4) > OH (2) for CMCD with a low DS and OH (6) > OH (2) > OH (4) for CMCD with relatively high DS. The increased carboxymethylation level induced the chain conformation transition of curdlan from triple helix to random coil in water. The DS of 0.25 was the critical value of chain conformation transition, below which CMCD chains were triple helices. For DS larger than 0.25, CMCD existed in the state of random coils. The intermolecular hydrogen bonding between C2 hydroxyls in AGU sustained the triple helical conformation and stiffness of the polymer chain, which weakened with the increase in DS.

Construction of Fully Biodegradable Poly(L-Lactide-Co-Caprolactone) Random Copolymer/Poly(D-Lactide) Blend: Crystallization, Toughness, and Biodegradability

Lei Gong,Yuesheng Zhang,Enyang Xu,Hongtao Lu,Junrui Duan,Jianna Bao

In this work, poly(L-lactide-co-ε-caprolactone) (PLCL) copolymers with varying ε-caprolactone (ε-CL) contents that ranged from 0% to 10% were synthesized via ring-opening polymerization of L-lactide and ε-CL at 170°C for 1 h. Fully biodegradable PLCL/poly(D-lactide) (PDLA) blends with stereocomplex (SC) crystallites were fabricated through a solution blending approach. The effects of ε-CL content in PLCL on the crystallization behavior, thermal properties, mechanical performance, and degradation behavior of PLCL/PDLA blends were systematically investigated. The successful synthesis of PLCL was confirmed by 1 H NMR and FTIR analyses. The melting peaks observed in the high-temperature region and the characteristic diffractions in WAXD patterns provided evidence for the formation of SC crystallites in PLCL/PDLA blends. Compared with PLCL, the incorporation of PDLA significantly enhanced the crystallization rate, due to the nucleation function of SC crystallites. With increasing ε-CL content in the copolymer system, the T g and crystallinity of PLCL gradually reduced, and the melting peaks of HC and SC crystals shifted toward lower temperatures due to the reduced sequence regularity. A pronounced improvement in deformability was achieved by the presence of ε-CL segments. As the ε-CL content increased from 1.5% to 10%, the elongation at break rose from 12% to 192%, with the morphology of elongated fibrils. Higher ε-CL contents accelerated enzymatic degradation, with mass loss exceeding 75% after 7 days at 10% ε-CL, because the increased chain mobility may facilitate the penetration of water and Proteinase K into the blend, thereby promoting enzymatic erosion. Overall, high-performance PLA-based composites with excellent biodegradability were achieved via SC crystallization and modulation of ε-CL comonomer content. Summary PLCL copolymers with tunable ε-CL content were prepared and characterized. SC crystallization regulated the crystallization and thermal behavior. ε-CL segments enhance chain mobility and improve blend deformability. Enzymatic degradation kinetics were accelerated as ε-CL content increased.

Tuning the d-Band center of High-Entropy oxides for selective aromatic oxidation and viscosity reduction in heavy oil

Lian Chen,Zhaofei Ma,Yu Jiang,Yuanzhu Mi,Yancheng Zheng,Xuemin Yan

Despite abundant global reserves, the industrial utilization of heavy oil is severely limited by its extremely high viscosity, primarily caused by the aggregation of polycyclic aromatic hydrocarbons (PAHs). In this study, we propose a novel viscosity reduction strategy using spinel-structured high-entropy oxides (HEOs) as low-temperature catalysts requiring no additional oxidants, representing a significant departure from conventional thermal and oxidative methods. By tuning the d-band centers of multicomponent metal sites, the electronic structure of HEOs is optimized to selectively activate and moderately oxidize aromatic-rich asphaltenes. This catalytic process disrupts π–π stacking and introduces oxygen-containing functional groups, triggering a fundamentally new, irreversible viscosity reduction mechanism driven by molecular fragmentation and polarity modulation. Experimental validations, including rheological measurements, spectroscopic analysis, and model compound studies, reveal a substantial viscosity reduction of ∼ 75.05%. Mechanistically, the partial oxidation of asphaltenes promotes molecular disorder, releases trapped light components from the condensed matrix, and facilitates the penetration of surfactants, thereby lowering the oil–water interfacial tension. Overall, this work establishes HEOs as a next-generation catalytic platform and presents a new pathway for efficient and sustainable heavy oil mobility enhancement.

MXene quantum dots induced Ni site d-band center self-optimization for advanced photovoltaic-driven urea-assisted water splitting

Yufeng Jiang,Shaobin Li,Li Zhang,Yang Yang,Kun Cheng,Fengbo Li,Xiaoqing Lv

Urea-assisted electrolytic water splitting for hydrogen production represents an effective contemporary strategy for generating green hydrogen. The sluggish kinetics of the anodic urea oxidation reaction (UOR) and cathodic hydrogen evolution reaction (HER) limit their practical application. The MXene quantum dots (MQDs) promote pronounced d-d orbital hybridization between Ni and Mo sites. The constructed heterostructures facilitate electron transfer and modulate charge redistribution. The extensive formation of heterostructures between numerous quantum dots and nickel molybdate results in the emergence of flower-like clusters at the tips of rod-like NiMoO 4 particles. The augmentation of the specific surface area results in the exposure of a larger quantity of active sites, which facilitates the redistribution of charge across these active sites, consequently enhancing the hydrolytic activity. The electrocatalyst exhibits remarkable performance in both the UOR and HER, achieving 1.31 V and 55 mV at 10 mA cm –2 , respectively. The catalyst for urea–assisted water electrolysis requires only 1.38 V at 10 mA cm –2 . The prepared catalyst can be employed for seawater splitting and photovoltaic-driven hydrogen production. In-situ Raman spectrum confirms that Ni sites on the NiMoO 4 /MQDs surface transform into Ni–OOH under hydrolysis and subsequently govern the hydrolytic reaction. This work indicates that d-d orbital hybridization can provide pathways for electronic transitions, thereby enhancing charge-transfer efficiency and effectively lowering reaction energy barriers.

Honokiol-Loaded β-D-Glucan/Chitosan Nanoparticles with Antibacterial and Anti-Inflammatory Activities for Promoting MRSA-Infected Wound Healing

Background:Methicillin-resistantStaphylococcus aureus(MRSA) wound infections are a major clinical concern due to their high prevalence and the growing risk of antimicrobial resistance. Therefore, it is imperative to develop safe and effective therapeutic strategies.Methods: Herein, we fabricated a novel antibiotic-free nanodrug delivery system (HNK/DG-COS NPs) by loading honokiol (HNK), a hydrophobic natural antimicrobial agent, onto a dual-polysaccharide carrier composed of chitosan (COS) and β-D-glucan (DG), for the treatment of MRSA-infected wounds. COS endows the nanoparticles with synergistic antibacterial activity together with HNK, while DG improves their anti-inflammatory and tissue repair capacities. The physicochemical characteristics of nanoparticles, as well as their in vitro antibacterial and anti-inflammatory activities, were systematically evaluated. Furthermore, an MRSA-infected wound model was constructed to verify their therapeutic efficacy.Results: HNK/DG-COS NPs exhibited a spherical morphology with a uniform particle size of approximately 200 nm. In vitro experiments have shown that HNK/DG-COS NPs can significantly kill MRSA and inhibit biofilm formation. Scanning electron microscopy further revealed that the nanoparticles exerted antibacterial effects by disrupting the integrity of bacterial cell membranes. In LPS-stimulated RAW264.7 macrophages, treatment with HNK/DG-COS NPs significantly mitigated pro-inflammatory cytokine levels. Cell migration assays confirmed that nanoparticles effectively enhanced L929 cell migration. In vivo, treatment with HNK/DG-COS NPs significantly accelerated MRSA-infected wound healing in mice, mitigated inflammatory damage, stimulated collagen production and repaired damaged tissues.Conclusions: HNK/DG-COS NPs represent a promising antibiotic-free candidate for intervention against early-stage MRSA-infected wounds.

Quantum size–induced orbital splitting drives d–p hybridization for enhanced hydrogen evolution in anion-exchange membrane water electrolyzers

Hongxu Su,Shijie Liu,Sicheng Geng,Xu Xu,Xiao Wang,Qiong Gao,Mingyi Zhang,Xinzhi Ma,Lin Li

Electronic modulation in quantum-size catalysts plays a critical yet underexplored role in governing the hydrogen evolution reaction (HER) in anion-exchange membrane water electrolyzers (AEMWEs). Here, cobalt nanoparticles with tunable diameters (5–15 nm) encapsulated in nitrogen-doped carbon nanotubes (Co@NCNTs) were engineered to elucidate how size-dependent orbital evolution dictates HER activity in alkaline media. We found that a smaller particle diameter results in a better charge transfer capability. Besides, the in-situ Raman spectroscopy shows that Co@NCNTs with an optimized diameter preserve a stable Co–N–C vibration at 690 cm −1 throughout HER, while transiently forming surface C–OH species—key intermediates that promote water dissociation. Inverse and ultraviolet photoelectron spectroscopy (IPES/UPS) further reveal that the quantum-size-effect splits the d -band and gives rise to a stronger Co 3 d –O 2 p hybridization. This enhanced hybridization facilitates electronic delocalization across Co–N–C/O interfaces, enabling dynamic charge transfer that favors the formation and subsequent reduction of C–OH intermediates during HER. As a result, the optimized Co@NCNTs catalyst achieves an overpotential of only 33 mV at 10 mA cm −2 and delivers 550 h operational stability in a full AEMWE. These findings provide direct experimental evidence that quantum-size-tailored orbital coupling governs interfacial OH/H 2 , thereby linking spectroscopic insight with catalytic function and establishing a rational design principle for high-performance non-noble-metal catalysts.

Phosphorus-induced d-p orbital hybridization in PtFeCoCuMo alloys: Regulating active hydrogen supply to enhance alkaline hydrogen evolution reaction

Zixuan Deng,Shuang Zhang,Fudong Li,Yue Zhu,Changsheng Shan,Yuanmeng Zhao

Rationally designing electrocatalyst/electrolyte interfaces with excellent active hydrogen supply capability is crucial for the hydrogen evolution reaction (HER), a core step in alkaline anion exchange membrane water electrolysis (AEMWE). Herein, phosphorus (P)-surface-coordinated PtFeCoCuMo quinary alloys are synthesized via a two-step wet-chemical method. P-induced d-p orbital hybridization enables the synergistic regulation of two key factors: it optimizes the hydrogen adsorption free energy (ΔG H∗ ) and water dissociation barrier (thermodynamic modulation), while tailoring the potential of zero charge (PZC) to accelerate proton transport (kinetic modulation). The optimized P 16 -PtFeCoCuMo catalyst exhibits outstanding alkaline HER activity, with a turnover frequency (TOF) 5-fold and 3-fold higher than those of commercial Pt/C and pristine PtFeCoCuMo alloy, respectively. This work overcomes thermodynamic and kinetic limitations simultaneously through heteroatom doping, providing a promising strategy for the design of high-performance alkaline HER catalysts.

Protective effects of Angelica dahurica polysaccharide on oxidative stress and liver injury induced by ovariectomized/D-galactose in rats

Xue-qin He,Yi-zhang Li,Li-ba Xu,Chun-feng Wu,Du-dong Wei,Hao-yu Liu,Fen Qiu

Background Oxidative stress-induced liver injury can progress to severe hepatic conditions. Polysaccharides are promising therapeutic agents, but the protective effects of Angelica dahurica polysaccharide (ADP) against this injury remain unclear.Purpose This study was conducted to elucidate ADP's protective effects and underlying molecular mechanisms in Ovariectomize/D-galactose (OVX/D-Gal) rats.Methods Fifty female OVX rats and ten sham-operated (SO) rats were randomly divided into six groups. Except SO group, rats were administered the corresponding doses of ADP and resveratrol respectively, and the model was established by 49-day daily subcutaneous D-Gal injection. Serum and liver samples were collected to examine the hepatic histopathological changes, oxidative stress-related biomarkers, inflammatory factors, and protein and gene expression levels.Results ADP reduced serum ALT and AST levels (P < 0.01) and improved liver histology. ADP increased SOD and GSH-Px activities , decreased MDA levels (P < 0.05). ADP also lowered pro-inflammatory cytokines levels, upregulated Nrf2, HO-1, and NQO-1 expression, promoted Bcl-2 and suppressed Bax and cleaved caspase-3 (P < 0.05).Conclusions ADP alleviated OVX/D-Gal-induced oxidative stress and liver injury by increasing antioxidant capacity, inhibiting apoptosis, attenuating inflammation, and activating Nrf2/HO-1/NQO-1 signaling pathway.

Chiisanoside Ameliorates d-Galactose-Induced Age-Related Hearing Loss by Modulating Autophagy and Ferroptosis via the SESN2/AMPK Axis

Wang Haijing,Gao Jie,Bai Xuefei,Liu Xiaofeng,Qu Shurong,Gao Yugang,Zhao Yan,Teng Hongbo

Age-related hearing loss (ARHL) is a pervasive sensorineural deficit lacking effective pharmacological interventions. Although Eleutherococcus senticosus fruit extracts exhibit otoprotective potential, their precise bioactive constituents and underlying molecular mechanisms remain elusive. Using network pharmacology and transcriptomic analysis as hypothesis-generating tools, followed by experimental validation, this study identifies chiisanoside (CSS) as a key bioactive compound mitigating d -galactose-induced cellular senescence and auditory impairment, with an optimal effective dose of 25 μM in vitro (HEI-OC1 cells) and 50 mg/kg/day in vivo (oral gavage in C57BL/6 mice). Mechanistically, the in vitro and in vivo models demonstrate that CSS suppresses age-related auditory decline primarily by targeting the SESN2/AMPK signaling axis. Specifically, CSS upregulates SESN2 to activate AMPK, which not only enhances autophagy via the mTOR/ULK1 pathway but also concurrently inhibits the HIF-1α/TFRC/FTH1 cascade. These findings provide mechanistic insights supporting the potential of CSS as a therapeutic candidate in ARHL.

Hyaluronic acid-ethylenediamine-cinnamic acid attenuates IBS-D via regulating 5-hydroxytryptamine signaling pathway, intestinal barrier and gut microbiota

Li Cui,Rongling Zhong,Wanqiu Peng,Zhenhai Zhang,Zhentao An,Hui Li

Current clinical management of diarrhea-predominant irritable bowel syndrome (IBS-D) faces substantial challenges due to the limited efficacy of existing therapeutic strategies. This study aimed to synthesize and characterize the hyaluronic acid-ethylenediamine-cinnamic acid conjugate (HA-EDA-CA), investigate its oral bioavailability and colonic tissue distribution, and validate its therapeutic potential along with underlying mechanisms of action in IBS-D models. Following oral administration of free CA or HA-EDA-CA, the colon concentration of CA released from the derivative was significantly higher than that of free CA alone. Both free and conjugated forms of CA likely contributed to the therapeutic effects against IBS-D. The IBS-D model was established by a combination of senna decoction administration and physical restraint stress. After HA-EDA-CA intervention, IBS-D model mice showed marked improvements in stool consistency, fecal water content, stool output, body weight, visceral hypersensitivity, and colon length. ELISA results indicated significant reduction in enteric neurotransmitter levels, including 5-hydroxytryptamine, substance P, and vasoactive intestinal peptide, after oral gavage administration of HA-EDA-CA. Additionally, intestinal permeability assessment and immunofluorescence analyse revealed that HA-EDA-CA improved intestinal barrier function. Western blot analysis indicated HA-EDA-CA inhibited 5-hydroxytryptamine signaling pathway. Furthermore, HA-EDA-CA modulated gut microbiota composition. These findings suggested the potential of HA-EDA-CA as a promising therapeutic candidate for IBS-D treatment. Key novelties: (i) First colon-targeted CA-HA conjugate: We developed and characterized the first hyaluronic acid-based conjugate specifically designed for colon-targeted delivery of cinnamic acid. (ii) Multi-mechanism rescue: The conjugate simultaneously restores gut homeostasis by modulating the 5-hydroxytryptamine signaling pathway, enhancing intestinal barrier function, and rebalancing gut microbiota. (iii) Enhanced therapeutic efficacy: HA-EDA-CA demonstrates superior colonic drug accumulation and integrated therapeutic outcomes compared to free cinnamic acid or simple drug mixtures. (iv) Open-source data availability: All relevant data and analysis scripts supporting the findings are publicly accessible to ensure reproducibility and further research.

A novel volumetric absorber integrated with low-cost D-Mannitol and acetylene-black nanoparticles for solar-thermal-electricity generation

Xusheng Zhang,Zheng Du,Yudong Zhu,Chuan Li,Xianfeng Hu,Tingbin Yang,Bin-Bin Yu,Rui Gu,Yulong Ding,Zhubing He

Low-medium temperature phase change materials (PCMs) act as a predominant role in one-sun solar thermal energy conversion and storage, attracting increasing attention in recent years. However, highly thermal conductive PCMs relying on the doping of a high dose of thermally conductive particles would limit the light absorption just at its top surface and decrease its bulk thermal storage density. In this work, we designed a volumetric solar absorber integrated with a D-Mannitol (DM) based PCM loaded with a low concentration (0.05 wt%) of acetylene black nanoparticles other than a high concentration of over 5 wt%. Such a method maintains a high phase change enthalpy of DM (295.2 kJ/kg) while achieving an enhanced heat transfer and hence a uniform temperature distribution . Compared to conventional surface absorbers with PCM, the volumetric absorber significantly reduces the temperature difference inside the bulk materials, from 103.1 °C of the surface absorber to 62.7 °C of the volumetric absorber with a thickness of 10 mm. Their photo to thermal charge and discharge performance was investigated for the first time in their based solar thermoelectric generator (STEG) system, which show that the volumetric absorber could reach 198.2 °C on bottom of the PCM and the corresponding open circuit voltage is 0.65 V. Such performance data are significantly better than the corresponding results from the surface absorber of 135.1 °C and 0.45 V, respectively, demonstrating successfully the significant performance enhancement by our volumetric absorber. This paper definitely deepens our understanding of volumetric absorbers and their based device design and applications in solar-thermal-electricity systems.

Polymer composites with enhanced thermal conductivity via oriented boron nitride and alumina hybrid fillers assisted by 3-D printing

Mengjing Liu,Sun-Wai Chiang,Xiaodong Chu,Jia Li,Lin Gan,Yanbing He,Baohua Li,Feiyu Kang,Hongda Du

Herein, oriented boron nitride (BN)/alumina (Al 2 O 3 )/polydimethylsiloxane (PDMS) composites were obtained by filler orientation due to the shear-inducing effect via 3-D printing. The oriented BN platelets acted as a rapid highway for heat transfer in the matrix and resulted in a significant increase in the thermal conductivity along the orientation direction. Extra addition of spherical Al 2 O 3 enhanced the fillers networks and resulted in the dramatic growth of slurry viscosity. This, together with filler orientation induced the synergism and provided large increases in the thermal conductivity . A high orientation degree of 90.65% and in-plane thermal conductivity of 3.64 W/(m∙K) were realized in the composites with oriented 35 wt% BN and 30 wt% Al 2 O 3 hybrid fillers. We attributed the influence of filler orientation and hybrid fillers on the thermal conductivity to the decrease of thermal interface resistance of composites and proposed possible theoretical models for the thermal conductivity enhancement mechanisms.