JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY
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2010
·Vol. 48
·期 23
·5364-5374
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IF 3.971
You-Mei Bao,Xiao-Hui Liu,Xiu-Lan Tang,Yue-Sheng Li
A series of novel hyperbranched poly(ester-amide)s (HBPEAs) based on neutral α-amino acids have been synthesized via the “AD + CBB′” couple-monomer approach. The ABB′ intermediates were stoichiometrically formed through thio-Michael addition reaction because of reactivity differences between functional groups. Without any purification, in situ self-polycondensations of the intermediates at elevated temperature in the presence of a catalyst afforded HBPEAs with multihydroxyl end groups. The degrees of branching (DBs) of the HBPEAs were estimated to be 0.40–0.58 and 0.24–0.54 by quantitative 13 C NMR with two different calculation methods, respectively, depending on polymerization conditions and structure of monomers. The influences of catalyst, temperature, and intermediate structure on the polymerization process and molecular weights as well as properties of the resultant polymers were investigated. FTIR, NMR, and DEPT-135 NMR analyses revealed the branched structure of the resultant polymers. The HBPEAs possess moderately high molecular weights with broad distributions, glass transition temperatures in the range of −25.5 to 36.5 °C, and decomposition temperatures at 10% weight loss under nitrogen and air in the regions of 243.4–289.1 °C and 231.4–265.6 °C, respectively. Among them, those derived from D , L -phenylalanine display the lowest degree of branching, whereas the highest glass transition temperature and the best thermal stability. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010
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ACS Infectious Diseases
·
2024
·
IF 4
Shu Li,Zhaopeng Wang,Shibo Song,Yuanyuan Tang,Jingjing Zhou,Xiaojing Liu,Xingjiao Zhang,Min Chang,Kairong Wang,Yali Peng
Multidrug resistance against conventional antibiotics has dramatically increased the difficulty of treatment and accelerated the need for novel antibacterial agents. The peptide Tat (47–57) is derived from the transactivating transcriptional activator of human immunodeficiency virus 1, which is well-known as a cell-penetrating peptide in mammalian cells. However, it is also reported that the Tat peptide (47–57) has antifungal activity. In this study, a series of membrane-active hydrocarbon-stapled α-helical amphiphilic peptides were synthesized and evaluated as antibacterial agents against Gram-positive and Gram-negative bacteria, including multidrug-resistant strains. The impact of hydrocarbon staple, the position of aromatic amino acid residue in the hydrophobic face, the various types of aromatic amino acids, and the hydrophobicity on bioactivity were also investigated and discussed in this study. Among those synthesized peptides, analogues P3 and P10 bearing a l-2-naphthylalanine (Φ) residue at the first position and a Tyr residue at the eighth position demonstrated the highest antimicrobial activity and negligible hemolytic toxicity. Notably, P3 and P10 showed obviously enhanced antimicrobial activity against multidrug-resistant bacteria, low drug resistance, high cell selectivity, extended half-life in plasma, and excellent performance against biofilm. The antibacterial mechanisms of P3 and P10 were also preliminarily investigated in this effort. In conclusion, P3 and P10 are promising antimicrobial alternatives for the treatment of the antimicrobial-resistance crisis.
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ENZYME AND MICROBIAL TECHNOLOGY
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2025
·
IF 3.7
Yaqi Fu,Siyu Mao,Tianyue Liao,Wei Feng
The enzyme OleT can utilize H 2 O 2 as the co-substrate, and this biocatalysis is an H 2 O 2 -driven enzymatic catalysis. In this work, OleT was recombinated by being fused to an elastin-like polypeptide (ELP). The recombinant enzyme OleT-ELP exhibits higher stability and resistance to H 2 O 2 interference compared to native OleT. OleT-ELP showed improved catalytic efficiency in producing α-olefins via fatty acid decarboxylation. The recombinant 5-hydroxymethylfurfural oxidase ( HMFO-ELP) catalyzes the oxidation of 5-hydroxymethylfurfural (HMF) to 2,5-furandicarboxylic acid (FDCA), generating H 2 O 2 as a byproduct. Combining OleT-ELP with HMFO-ELP enabled simultaneous conversion of fatty acids and HMF. The in situ H 2 O 2 generated by HMFO-ELP was transferred to OleT-ELP, enhancing catalytic efficiencies for both α-olefins and FDCA production.
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EXPERIMENTAL NEUROLOGY
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2024
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IF 4.6
Jing Qiu,Yi-Han Wang,Xiu-Ming Wang,Hui-Sheng Chen
The pericytes (PCs) surrounding capillaries are vital regulators of capillary constriction. Persistent PC contraction results in the increased capillary constriction, therefore leading to the impaired cerebral blood flow (CBF) recovery after reperfusion and worsening the clinical outcomes in stroke patients. However, the potential determinants of PC functions during ischemia/reperfusion are poorly understood. Phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit Delta (PIK3CD/PI3Kδ) is a crucial factor involved with neuronflammation during ischemic stroke. PI3Kδ has shown the expression in PCs, while its effect on PC functions has not been explored yet. In this study, a rodent ischemia/reperfusion model was established in C57BL/6 mice via transient middle cerebral artery occlusion and reperfusion (MCAO/R). The PI3Kδ expression in ischemic penumbra was remarkably upregulated following MCAO/R induction. PI3Kδ inhibitor CAL-101 improved the CBF recovery, ischemic brain injury, and suppressed capillary constriction in MCAO/R mice. Besides, the production of tumor necrosis factor alpha (TNF-α), an inducer for tissue injury, and the expression of transient receptor potential vanilloid type 2 (TRPV2), a channel protein permitting calcium (Ca 2+ ) uptake, were significantly reduced in ischemic penumbra after CAL-101 treatment. In vitro, oxygen-glucose deprivation and reoxygenation (OGD/R) enhanced the expression of PI3Kδ and TRPV2 in primary mouse PCs. CAL-101 suppressed the TNF-α-induced TRPV2 expression in OGD/R-treated PCs, thus inhibiting the Ca 2+ uptake and PC contraction. Collectively, this study suggests that PI3Kδ is a critical regulator of PC function during ischemic stroke.
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JOURNAL OF PHARMACEUTICAL AND BIOMEDICAL ANALYSIS
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2024
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IF 3.1
Xinlin Chen,Ying Wu,Sifang Wu,Yucheng Gu,Jianguang Luo,Lingyi Kong
Identifying medicinally relevant compounds from natural resources generally involves the tedious work of screening plants for the desired activity before capturing the bioactive molecules from them. In this work, we created a paper-based ligand fishing platform to vastly simplify the discovery process. This paper-based method exploits the enzymatic cascade reaction between α -glucosidase (GAA), glucose oxidase (GOx), and horseradish peroxidase (HRP), to simultaneously screen the plants and capture the GAA inhibitors from them. The designed test strip could capture ligands in tandem with screening the plants, and it features a very simply operation based on direct visual assessment. Multiple acylated flavonol glycosides from the leaves of Quercus variabilis Blume were newly found to possess GAA inhibitory activities, and they may be potential leads for new antidiabetic medications. Our study demonstrates the prospect of the newly discovered GAA ligands as potential bioactive ingredients as well as the utility of the paper-based ligand fishing method.
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Advanced Science
·
2025
·
IF 14.1
Zhuo Chen,Tianyu Liu,Irfan Ismail,Fan Qian,Lianping Zhang,Shutao Yang,Xiaoke Zhang,Lingpeng Yan,Yunfei Han,Qun Luo,Yongzhen Yang,Chang-Qi Ma
The conductivity of AgNWs electrodes can be enhanced by incorporating Ag grids, thereby facilitating the development of large-area flexible organic solar cells (FOSCs). Ag grids from vacuum evaporation offer the advantages of simple film formation, adjustable thickness, and unique structure. However, the complex 3D multi-component structure of AgNWs electrodes will exacerbate the aggregation of large Ag particles, causing the device short circuits. To address this issue, the relationship between the surface energy of modification layers and the morphology and conductivity of ultrathin Ag on AgNWs is studied. The amorphous ZnO (α-ZnO) layer promotes Ag growth from Volmer–Weber (VW) to Frank–Van der Merwe (FM), reducing particle aggregation. The 1 µm thick PET/AgNWs/Ag grid electrode with α-ZnO exhibited low contact resistance and high conductivity. As a result, 1 cm 2 FOSCs with Ag grids achieve a power conversion efficiency (PCE) of 16.01%. As the area increased to 4 and 9 cm 2 , the performance of the monolithic FOSCs is 14.70% and 12.69%, showing less efficiency loss during upscaling. The 8 and 16 cm 2 modules constructed by series and parallel connection of the monolithic devices yield PCEs of 14.47% and 12.92%, respectively. This study offers valuable insights into constructing Ag grids on AgNWs electrodes for highly efficient large-area FOSCs.
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CONSTRUCTION AND BUILDING MATERIALS
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2025
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IF 8
Mingxia Wu,Chang Chen,Shaowu Jiu,Yanxin Chen,Yan Liu
Salt gypsum (SG), a by-product derived from the salt manufacturing process, poses considerable challenges for efficient reuse owing to its elevated moisture and salt content. In this study, an innovative methodology was developed utilizing an oil-bath reaction unit to synthesize α-calcium sulfate hemihydrate (α-HH) from untreated SG in a sodium chloride (NaCl) solution, with the objective of achieving environmentally sustainable production. The influence of NaCl concentration, the type and content of transcrystallizing agents, reaction temperature, reaction duration, and stirring rate on the transformation process, crystal morphology, and mechanical strength of α-HH was systematically examined. The crystal morphology and chemical composition of the resultant α-HH products were meticulously characterized through XRD, SEM, EDS, FT-IR, and TG-DSC. The findings revealed that under optimized conditions (15 wt% NaCl solution, a reaction temperature of 115°C, a reaction duration of 2.0 h, a stirring rate of 200 rpm, and 0.20 wt% sodium succinate as a crystal modifier), the conversion efficiency of α-HH attained 80.90 %, accompanied by a compressive strength of approximately 31.93 MPa post-drying. NaCl induced a transformation in crystal morphology from flaky to long columnar, whereas sodium succinate further refined the morphology from long columnar to short columnar via physical adsorption mechanisms. This study proposes a high-value strategy for the valorization and recycling of industrial by-product gypsum, thereby broadening the application scope of SG and significantly enhancing its overall utilization efficiency. This approach is of paramount importance for advancing the green and sustainable development of the salt chemical industry.
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Analytical Science Advances
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2025
·Vol. 6
·期 2
·e70037
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IF 4.1
Dan-ping Liu,Bi-cheng Yang,Qiao-yun Huang,Ping Liu,Hai-yan Luo,Mao-lin Yu,Jian-qiong Yang,An Jia,Yan-qiu Liu,Lin Xu,Bin Hu,Ting Huang
In this work, we developed a matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS) method to directly analyze human whole blood samples. 1.0 µL of whole blood samples and 1.0 µL of optimized organic matrix were directly loaded onto the sample plates for MALDI-TOF-MS detection. A total of 59 whole blood samples were investigated in this work, including 23 healthy control samples, 28 α-globin gene triplication carriers with α-chain repetition, and eight deletional hemoglobin H disease (HbH) patients with α-chain deficiency. Human hemoglobin (Hb) chains with high signal-to-noise were directly observed. It is found that there is a change in signal ratios of α/β-chains of Hb from blood samples in thalassemia subtypes by comparing the ratios obtained from healthy blood samples. Analytical variability ( n = 6) of signal ratios of α/β-chains was found to be 3.33%–12.86% (intra-day), 4.02%–13.39% (inter-day), and 6.41%–15.32% (inter-laboratory), respectively. Furthermore, the results were validated using different MALDI-TOF MS approaches. Our results suggest that α/β-chains ratios of Hb could be an indicator for investigating thalassemia by MALDI-TOF-MS.
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Molecular Catalysis
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2025
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IF 4.9
Huan-huan Fan,Wei Su,Jing-zhi Wu,Wen-long Liu,Chu-an Lin,Qing-yun Li,You-yan Liu,Ai-xing Tang
This study addresses challenges in the chemoenzymatic epoxidation of α-pinene, such as lipase deactivation, carrier decomposition in acidic environments, and product ring-opening side reactions, by developing a core-shell structured metal-organic framework (MOF)-based immobilized enzyme catalyst, CALB@ZIF-8@Zn-BTC. Candida antarctica lipase B (CALB) was encapsulated into ZIF-8 channels via in situ encapsulation. Trisodium citrate was introduced to accelerate the aggregation and co-precipitation of ZIF-8, while 1,3,5-benzenetricarboxylic acid (H₃BTC) coordinated with surface zinc ions of ZIF-8 to form a core-shell composite with enzyme protection and acid-buffering functionalities. Experimental results demonstrated that sodium citrate significantly enhanced acid scavenging capacity, suppressing acidic side reactions and achieving 96.6 % epoxidation selectivity. The Zn-BTC shell improved ZIF-8 stability in acidic systems, retaining over 60 % activity after 7 cycles. Under optimized conditions (3.35 mol/L ethyl acetate, 0.5 mol/L H₂O₂, 0.1 g sodium citrate), α-pinene conversion reached 83.1 %. Compared to the commercial catalyst Novozym435, CALB@ZIF-8@Zn-BTC exhibited superior catalytic efficiency, selectivity, and reusability. Structural characterization (FESEM, EDS, nitrogen adsorption) confirmed enhanced mass transfer and stability due to the composite’s unique architecture and uniformly distributed sodium citrate. This work provides an innovative solution for green and efficient α-pinene epoxidation and offers theoretical and practical insights for designing MOF-based catalysts in acidic environments.
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Molecular Catalysis
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2025
·
IF 4.9
Hao Zhang,Weiping Yang,Wenjing An,Kai Yu,Shuangxi Liu,Lan-lan Lou
The development of highly efficient and recyclable bifunctional photoredox catalysts is extremely promising for organic synthesis. In this study, a novel kind of bifunctional metal-organic framework (MOF) based catalysts were prepared through the in-situ incorporation of the L -proline moiety into the MOF network and followed by the anchoring of dye molecules via a solvothermal process. These catalysts exhibited versatile catalytic activity in the visible light triggered α -alkylation of aldehydes and cross-dehydrogenative coupling reactions between N -aryl tetrahydroquinolines and ketones. The control experiments revealed enhanced synergy existed between the two kinds of catalytic active centers confined in the porous framework, resulting in significantly enhanced catalytic activities while maintaining comparable enantioselectivities to the corresponding homogeneous catalytic systems. Furthermore, the bifunctional catalysts showed high stability and reusability over five consecutive cycles with only a slight decrease in activity. Based on the experimental results, a plausible reaction mechanism over the present bifunctional catalyst was proposed.
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Materials Today Communications
·
2025
·
IF 4.5
Xiao Wang,Xiaoyu Wang,Xiang Lu,Rongyan Hu,Yutong Li,Xinyi Wang,Shihao Ma,Zuguang Liu
With the rise of green chemistry and cleaner production, the carbon-based solid acids as environment-friendly catalysts have received increasing attention worldwide. In this paper, A composite catalyst was obtained by a combination of sulfonated glucose (SG) and p -toluenesulfonic acid (PT), and identified as a catalyst for the esterification reaction between α -pinene and acetic acid (AC). It is demonstrated that the composite catalyst, possessing a high density of active sites (1.59 mmol/g of sulfonic acid and 5.05 mmol/g of total acid, respectively) and mesoporous structure (5.7 nm), demonstrates outstanding catalytic activity with a conversion of α -pinene reaching 100 % and a selectivity of 51.2 % for total ester under optimum reaction conditions. Kinetic analysis shows that the esterification reaction behaves according to pseudo-first-order kinetics, featuring an activation energy of 135.86 kJ/mol. Moreover, the thermodynamic enthalpy (Δ H ) and Gibbs free energy (Δ G ) associated with the esterification reaction are 133.05 kJ/mol and 85.86 kJ/mol, respectively, implying that this reaction is endothermic and not spontaneous. Moreover, the catalyst has been shown to be reusable up to 4 times while retaining high catalytic activity. Overall, the catalyst has demonstrated significant potential as a heterogeneous catalyst for transforming α -pinene into valuable acetates.
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Microbial Biotechnology
·
2024
·Vol. 17
·期 4
·e14455
·
IF 4.8
Xuke Yang,Jichao Yang,Mengyu Lyu,Yaqiong Li,Anqi Liu,Bang Shen
Toxoplasma gondii is a zoonotic parasite infecting humans and nearly all warm-blooded animals. Successful parasitism in diverse hosts at various developmental stages requires the parasites to fine tune their metabolism according to environmental cues and the parasite's needs. By manipulating the β and γ subunits, we have previously shown that AMP-activated protein kinase (AMPK) has critical roles in regulating the metabolic and developmental programmes. However, the biological functions of the α catalytic subunit have not been established. T. gondii encodes a canonical AMPKα, as well as a KIN kinase whose kinase domain has high sequence similarities to those of classic AMPKα proteins. Here, we found that Tg KIN is dispensable for tachyzoite growth, whereas Tg AMPKα is essential. Depletion of Tg AMPKα expression resulted in decreased ATP levels and reduced metabolic flux in glycolysis and the tricarboxylic acid cycle, confirming that Tg AMPK is involved in metabolic regulation and energy homeostasis in the parasite. Sequential truncations at the C-terminus found an α-helix that is key for the function of Tg AMPKα. The amino acid sequences of this α-helix are not conserved among various AMPKα proteins, likely because it is involved in interactions with Tg AMPKβ, which only have limited sequence similarities to AMPKβ in other eukaryotes. The essential role of the less conserved C-terminus of Tg AMPKα provides opportunities for parasite specific drug designs targeting Tg AMPKα.
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