The Inhibitory Effects of PSS-Loaded Nanoparticles on the Dysfunction of Cardiac Microvascular Endothelia in Rats with Diabetic Cardiomyopathy

Propylene glycol alginate sodium sulfate-loaded nanoparticles(PSS-NP) has been shown potential to prevent the microvascular endothelial injuries caused by diabetic cardiomyopathy(DCM). In this study, we aimed to investigate the effects of PSS-NP on the dysfunction of cardiac microvascular endothelia in streptozotocin(STZ)-induced DCM rat model. Echocardiographic measurements showed a significant improvement of cardiac function in the PSS-NP-treated group. Our results revealed that the abnormalities of cardiac systolic and diastolic functions were suppressed by the treatments of prostaglandin E1(PGE1), low molecular weight heparin(LMWH), PSS and PSS-NP. Our comparison analysis indicated that PSS-NP showed the strongest inhibitory effects on microvascular endothelial injuries. Transmission electron microscopy analysis demonstrated that PSS-NP protected the cardiac microvascular endothelium and further improved endothelium dysfunction in DCM rats. ELISA and Western blot assays further showed a high efficiency of improving cardiac microvascular endothelial dysfunction with PSS-NP. Our results demonstrated that PSS-NP increased the protein expression of phosphatidylinositol 3-kinase(PI3K)-p85 and vascular endothelial growth factor(VEGF)-A, and the phosphorylation of protein kinase B(Akt) and endothelial nitric oxide synthase(eNOS), which were involved in the amelioration of cardiac microvascular endothelial dysfunction. These data suggest that PSS-NP may be a novel approach to the treatment the coronary microcirculation disorder diseases such as DCM.     

Comparative toxic effects of copper-based nanoparticles and their microparticles in Daphnia magna by using natural freshwater media

Copper-based nanoparticles (NPs) are being widely used in different application fields and their health impacts to aquatic environments represent a current concern. Few studies are available about their comparative toxicity with their bulks and ions under natural exposition in aquatic organisms. Thus, the toxicity of Cu and CuO NPs and their microparticle and ionic forms was assayed in the acute immobilisation test of Daphnia magna by using freshwater media. Electronic microscopy, laser doppler velocimetry, and dynamic laser scattering methodologies were used to NPs characterisation. The results indicated that CuNPs and CuONPs were more toxic than their microparticles. Among NPs, CuNPs showed higher toxicity than CuONPs. Copper-based nanoparticles showed similar hydrodynamic particle size and were agglomerated in culture media, suggesting toxic-ionic release relationship and corroborated by the high toxicity induced by CuSO₄. Additionally, water chemistry of natural freshwater used in the experiments also favoured the ion release of these NPs.     

The aggregation behavior and formation of nanoparticles of oleoylchitosan in dilute aqueous solution

Oleoylchitosans (O-chitosans) with different degrees of substitution (DS) were synthesized by reacting chitosan with oleoyl chloride. The chemical structures of the products were characterized by 1H NMR and FT-IR. These results suggested the for-mation of an amide linkage between the amino groups of chitosan and the carboxyl groups of oleic acid. The viscosity of O-chitosan sharply increased with the increase of concentration, whereas that of unmodified chitosan rose only slightly. This increase became larger as the DS increased. All of the O-chitosans could reduce surface tension slightly. The critical aggregation concentration (CAC) of O-chitosans with DS 5%, 11%, and 27% were 79.43 mgL-1, 31.6 mgL-1, and 10mgL-1, respectively. Nanoparticles were prepared using an O/W emulsification method. The mean diameters of the polymeric amphiphilic nanoparticles of O-chitosans with DS 5% and 11% were around 327.4 nm and 275.3 nm, respectively.     

具有良好热稳定性的勃姆石纳米粉体的制备及表征

以Al(NO3)3·9H2O与氨水作用制备出勃姆石(AlOOH)沉淀,通过超声胶溶将沉淀转化为勃姆石溶胶,向所获溶胶中加入聚乙二醇使之凝胶化,再经冷冻干燥脱水,得疏松勃姆石粉体.对该粉体及其煅烧产物进行SEM,XRD表征,发现400℃/2 h煅烧产物仍然为勃姆石相,表明此方法合成的勃姆石有良好的热稳定性,用Scherrer公式计算的晶粒尺寸为10 nm左右;1 200℃/2 h煅烧产物为结构疏松、粒度微细的θ-Al2O3及α-Al2O3混相产物.     

Dechlorination of 3,3′,4,4′-tetrachlorobiphenyl (PCB77) in water,by nickel/iron nanoparticles immobilized on L-lysine/PAA/PVDF membrane

In this study, the dechlorination of chlorinated hydrocarbon 3,3′,4,4′-tetrachlorobiphenyl (PCB77) by bimetallic Ni/Fe nanoparticles immobilized on L-lysine/PAA/PVDF membrane was investigated at ambient conditions through the batch mode operation. The membrane support polyvinylidene fluoride (PVDF) was modified by in situ polymerization of acrylic acid in aqueous phase, then L-lysine was covalently bonded to the polymerized acrylic acid chains with the aid of a water-soluble carbodiimide, 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide hydrochloride (EDC). The modification procedure involved cationic ion exchange with Fe²⁺, reduction to Fe⁰ with NaBH₄ and finally deposition of Ni⁰. The scanning electron microscopic images showed that the Ni/Fe nanoparticles were successfully immobilized inside the membrane using the polyacrylic acid (PAA) as an inter-linkage between PVDF and L-lysine. A systematic characterization of the composite was performed using ATR-FTIR, HRSEM, EDX, HRTEM, XRD, and contact angle measurement studies and a relatively uniform distribution of Ni/Fe was found in L-lysine/PAA/PVDF membrane because of its hydrophilic nature. The obtained Ni/Fe nanoparticles consist of Fe⁰ core surrounded by the Ni⁰ shell. The diameter of Ni/Fe nanoparticles was predominantly within the range 20–30 nm. The immobilized Ni/Fe nanoparticles exhibited a good reactivity towards the dechlorination of the chlorinated hydrocarbon since the concentration of the PCB77 was decreased by catalytic dechlorination with Ni/Fe nanoparticles inside the L-lysine/PAA/PVDF membrane. Dechlorination efficiency of 98% was achieved within 9 h.     

不同粒径TiO_2颗粒对海洋微藻的毒性效应

本实验以新月菱形藻为受试生物,研究了低浓度不同粒径TiO2颗粒(21nm、60nm和400nm)对海洋微藻生长、抗氧化酶活性(超氧化物歧化酶SOD、过氧化氢酶CAT和过氧化物酶POD)、脂质过氧化产物(MDA)含量的影响,并测定了相应的活性氧自由基(ROS)的含量,初步探讨了TiO2颗粒对海洋微藻的作用机制。结果表明,1mg/L TiO2颗粒对新月菱形藻生长的抑制作用随着粒径的减小而逐渐增强,第48h、72h、96h呈现出显著的纳米效应。TiO2颗粒可以诱导藻细胞内ROS的含量增加,对藻细胞产生氧化胁迫,新月菱形藻的抗氧化酶活性发生应激响应,以清除过量的ROS,但剩余的ROS对藻细胞产生氧化损伤,导致MDA含量升高,并且纳米级TiO2颗粒对新月菱形藻的氧化损伤大于微米级颗粒。在不同粒径TiO2颗粒的胁迫下,藻细胞SOD和CAT活性的响应也存在差异。本研究将为开展人工纳米材料对海洋生态系统影响的潜在风险评估提供科学依据。     

Spinel Ferrite Mediated Photo‐Fenton Degradation of Phenolic Analogues: A Detailed Study Employing Two Distinct Inorganic Oxidants

The present work demonstrates the applicability of ferrites as photo‐Fenton catalysts for deterioration of different phenolic derivatives. To analyze optimal reaction conditions, experiments are performed with four magnetic spinel ferrites MFe₂O₄ (M = Co, Cu, Ni, and Zn) and two inorganic oxidants, i.e., hydrogen peroxide (HP) and potassium peroxymonosulfate (PMS). The reactions are performed using p‐nitrophenol as phenolic probe. CuFe₂O₄ and CoFe₂O₄ possessed excellent ability to activate HP and PMS, respectively, among all four synthesized catalysts. A noteworthy aspect of two oxidizing agents is that the concentration of PMS used during the reaction is four times less than HP. Further, the broad pH activity of PMS provides a significant advantage over HP. The optimal reaction conditions, when HP is the oxidant in the photo‐Fenton degradation, are 0.50 g L^?1 MFe₂O₄, pH 2.5, and 8.8 mM HP. Although PMS is active in a wide pH range (2–10), adequate reaction conditions are 0.50 g L^?1 MFe₂O₄, natural pH, and 2.2 mM PMS. The photo‐Fenton activity of ferrites is extended to the degradation of different nitro‐ and chloro‐analogs of phenol (2‐nitrophenol, 3‐nitrophenol, 4‐nitrophenol, 2,4‐dinitrophenol, 2,4,6‐trinitrophenol, 2‐chlorophenol, 3‐chlorophenol, 4‐chlorophenol, 2,4‐dichlorophenol) with only two ferrites (CuFe₂O₄ and CoFe₂O₄). A comparative study is performed with the two oxidants (HP and PMS) with positive results. Finally, stability and reusability of magnetic ferrites as catalysts are also studied to prove their use in phenolic solution treatment.