Monitoring oxidative stability and changes in key volatile compounds in edible oils during ambient storage through HS-SPME/GC–MS

<p>Headspace solid-phase microextraction/gas chromatography–mass spectrometry (HS-SPME/GC–MS) analysis combined with ‘relative odour activity value (ROAV)’ was used to monitor changes in key volatile compounds in peanut oil, soybean oil, rapeseed oil, and linseed oil during ambient storage. Volatile composition and oxidation process were compared among edible oil samples. The differences in the volatile contents of edible oils led to their characteristic flavour. Aldehydes featured a relatively high content and low odour threshold and mainly contributed to the flavour of edible oils. The key flavour compounds included pentanal, hexanal, octanal, nonanal, <i>trans</i>-2-heptenal, and benzaldehyde, which are important oxidative degradation products of oleic acid and linoleic acid. The formation of key volatile oxidation compounds was affected by different oxidation processes during ambient storage. Certain aldehydes increased with oxidation level, whereas other aldehydes initially increased then decreased. Correlation analysis showed that the concentrations of several volatile compounds progressively increased during oxidation. The key volatile oxidation compounds formed during oil storage at ambient temperature are partly different from those generated at high temperatures. Volatile oxidation compounds can be a marker for monitoring the oxidation degree of edible oils during ambient storage.</p

Surface-Confined Crystalline Two-Dimensional Covalent Organic Frameworks <i>via</i> on-Surface Schiff-Base Coupling

We performed a co-condensation reaction between aromatic aldehyde and aromatic diamine monomers on a highly oriented pyrolytic graphite surface either at a solid/liquid interface at room temperature or in low vacuum with moderate heating. With this simple and moderate methodology, we have obtained surface-confined 2D covalent organic frameworks (COFs) with few defects and almost entire surface coverage. The single crystalline domain can extend to more than 1 μm². By varying the backbone length of aromatic diamines the pore size of 2D surface COFs is tunable from ∼1.7 to 3.5 nm. In addition, the nature of the surface COF can be modified by introducing functional groups into the aromatic amine precursor, which has been demonstrated by introducing methyl groups to the backbone of the diamine. Formation of small portions of bilayers was observed by both scanning tunneling microscopy (STM) and AFM, which clearly reveals an eclipsed stacking manner

3D Graphene Functionalized by Covalent Organic Framework Thin Film as Capacitive Electrode in Alkaline Media

To harness the electroactivity of anthraquinone as an electrode material, a great recent effort have been invested to composite anthraquinone with carbon materials to improve the conductivity. Here we report on a noncovalent way to modify three-dimensional graphene with anthraquinone moieties through on-surface synthesis of two-dimensional covalent organic frameworks. We incorporate 2,6-diamino-anthraquinone moieties into COF through Schiff-base reaction with benzene-1,3,5-tricarbaldehyde. The synthesized COF -graphene composite exhibits large specific capacitance of 31.7 mF/cm². Long-term galvanostatic charge/discharge cycling experiments revealed a decrease of capacitance, which was attributed to the loss of COF materials and electrostatic repulsion accumulated during charge–discharge circles which result in the poor electrical conductivity between 2D COF layers

On-Site Construction of a Full-Thickness Skin Equivalent with Endothelial Tube Networks via Multilayer Electrospinning for Wound Coverage

Novel full-thickness skin substitutes are of increasing interest due to the inherent limitations of current models lacking capillary networks. Herein, we developed a novel full-thickness skin tissue containing blood capillary networks through a layer-by-layer assembly approach using a handy electrospinning apparatus and evaluated its skin wound coverage potential in vivo. The average diameter and thickness of fabricated poly-ε-caprolactone-cellulose acetate scaffolds were easily tuned in the range of 474 ± 77–758 ± 113 nm and 9.43 ± 2.23–29.96 ± 5.78 μm by varying electrospinning distance and duration, as indicated by FE-SEM. Besides, keratinocytes exhibited homogeneous differentiation throughout the fibrous matrix prepared with electrospinning distance and duration of 9 cm and 1.5 min within five-layer (5L) epidermal tissues with thickness of 135–150 μm. Moreover, coculture of vascular endothelial cells, circulating fibrocytes, and fibroblasts within the 5L dermis displayed network formation in vitro, resulting in reduced inflammatory factor levels and enhanced integration with the host vasculature in vivo. Additionally, the skin equivalent grafts consisting of the epidermal layer, biomimetic basement membrane, and vascularized dermis layer with an elastic modulus of approximately 11.82 MPa exhibited accelerated wound closure effect indicative of re-epithelialization and neovascularization with long-term cell survival into the host, which was confirmed by wound-healing rate, bioluminescence imaging activity, and histological analysis. It is the first report of a full-thickness skin equivalent constructed using a battery-operated electrospinning apparatus, highlighting its tremendous potential in regenerative medicine