Antifungal Effect of Chitosan/Nano-TiO2 Composite Coatings against Colletotrichum gloeosporioides, Cladosporium oxysporum and Penicillium steckii.

Postharvest pathogens such as C. gloeosporioides (MA), C.oxysporum (ME) and P. steckii (MF) are the causal agents of disease in mangoes. This paper presents an in vitro investigation into the antifungal effect of a chitosan (CTS)/nano-titanium dioxide (TiO2) composite coating against MA, ME and MF. The results indicated that, the rates of MA, ME and MF mortality following the single chitosan treatment were 63.3%, 84.8% and 43.5%, respectively, while the rates of mycelial inhibition were 84.0%, 100% and 25.8%, respectively. However, following the addition of 0.5% nano-TiO2 into the CTS, both the mortality and mycelial inhibition rates for MA and ME reached 100%, and the mortality and mycelial inhibition rate for MF also increased significantly, reaching 75.4% and 57.3%, respectively. In the MA, the dry weight of mycelia after the CTS/0.5% nano-TiO2 treatment decreased by 36.3% in comparison with the untreated group, while the conductivity value was about 1.7 times that of the untreated group, and the protein dissolution rate and extravasation degree of nucleic acids also increased significantly. Thus, this research revealed the potential of CTS/nano-TiO2 composite coatings in the development of new antimicrobial materials.

Fatty acids-modified liposomes for encapsulation of bioactive peptides: Fabrication, characterization, storage stability and in vitro release.

The fragile membranes of liposomes limit their application by the food industry. In this study, we hypothesized that interactions between fatty acids with different chain lengths and phospholipids might enhance liposome stability. Decanoic acid modified liposomes (Lipo-DA) and stearic acid modified liposomes (Lipo-SA) were fabricated for encapsulation of hydrophilic peptides. Fluorescence spectroscopy and FTIR analysis showed molecular interactions existed between alkyl chains and phospholipids, resulting in greater compactness and hydrophobicity of the membranes in Lipo-DA and Lipo-SA. This led to a reduction in melting point characterized by differential scanning calorimetry analysis. Lipo-DA and Lipo-SA could delay the release of hydrophilic peptides compared with unmodified liposomes in simulated digestion. Moreover, Lipo-DA showed better stability during storage, while Lipo-SA exhibited precipitation, resulting in the lowest peptide retention. Our study showed that decanoic acid is suitable to enhance the stability of liposomes, although this approach has yet to be tested in food products.

GaN Nano Air Channel Diodes: Enabling High Rectification Ratio and Neutron Robust Radiation Operation.

Nano air channel transistors (NACTs) provide numerous advantages over traditional silicon devices, including faster switching speeds, higher operating frequencies, and enhanced radiation hardness attributable to the ballistic transport of electrons. In the development of field-emission-based integrated circuits, low-power consumption rectifying nano air channel diodes (NACDs) play a crucial role. However, achieving rectification characteristics in NACDs is challenging due to their structural and material symmetry. This paper proposes a vertical GaN NACD with a consistent nano air channel fabricated using IC-compatible processes. The GaN NACD exhibits an exceptionally low turn-on voltage of 0.3 V while delivering a high output current of 5.02 mA at 3 V. Notably, it demonstrates a high rectification ratio of up to 2.2 × 105, attributing to significant work function disparities within the GaN-Au structure, coupled with the reduction of Au surface roughness to minimize reverse current. Furthermore, the junction-free structure and superior material properties of GaN enable the NACD to be suitable for use in radiation-rich environments. With its potential as a fundamental component of ultrafast and ultrahigh-frequency integrated circuits, this intriguing and cost-effective rectifying diode is anticipated to garner widespread interest within the electronics community.

Fast Response GaN Nanoscale Air Channel Diodes with Highly Stable 10 mA Output Current toward Wafer-Scale Fabrication.

Nanoscale air channel transistors (NACTs) have received significant attention due to their remarkable high-frequency performance and high switching speed, which is enabled by the ballistic transport of electrons in sub-100 nm air channels. Despite these advantages, NACTs are still limited by low currents and instability compared to solid-state devices. GaN, with its low electron affinity, strong thermal and chemical stability, and high breakdown electric field, presents an appealing candidate as a field emission material. Here, a vertical GaN nanoscale air channel diode (NACD) with a 50 nm air channel is reported, fabricated by low-cost IC-compatible manufacturing technologies on a 2-inch sapphire wafer. The device boasts a record field emission current of 11 mA at 10 V in the air and exhibits outstanding stability during cyclic, long-term, and pulsed voltage testing. Additionally, it displays fast switching characteristics and good repeatability with a response time of fewer than 10 ns. Moreover, the temperature-dependent performance of the device can guide the design of GaN NACTs for applications in extreme conditions. The research holds great promise for large current NACTs and will speed up their practical implementation.

Photo-Induced Antifungal Activity of Chitosan Composite Film Solution with Nano-Titanium Dioxide and Nano-Silver.

ABSTRACT: This study was conducted to investigate the UV light-induced effect of chitosan-titanium dioxide-silver (CTS-TiO2-Ag) nanocomposite film solution against Penicillium steckii and the underlying physiological mechanism of this effect. With longer UV exposure time, pathogen inhibition increased. UV-photoinduced treatment for 120 min produced the smallest P. steckii colony diameter, at 4.85 mm. However, when this treatment was followed by 8 h of storage, the conductivity of the P. steckii culture medium reached its highest level, at 713 microsiemens per cm. After a 120-h growth period on mangoes under the same conditions, the lesion diameters and proportion of infected mangoes reached 12.61 mm and 41.67%, respectively. Because the P. steckii cell membrane was severely disrupted, its permeability increased, causing serious extravasation of intracellular protein and nucleic acid material. Malondialdehyde, catalase, and superoxide dismutase in the P. steckii cells reached maximum concentrations (2.1106 µmol/mL, 44.06 U/mL, and 24.67 U/mL, respectively) after 8 h of incubation. These results indicate significant P. steckii inhibition by the UV light induction of the CTS-TiO2-Ag nanocomposite film solution.

Effect of different superfine grinding technologies on the physicochemical and antioxidant properties of tartary buckwheat bran powder.

The effect of shear crushing, airflow comminution, and wet grinding on the physical and chemical properties of Tartary buckwheat bran (TBB) powder was compared. Superfine grinding significantly reduces the particle size of bran (1.644 µm), while increasing the protein content (23.60%), water-holding capacity (4.38 g g-1), solubility (21.077 g 100 g-1), bulk density (0.34 g mL-1), and tap density (0.53 g mL-1) providing good processing characteristics. The antioxidant properties of bran powder prepared by the three methods mentioned above were compared. The results showed that different bran powders subjected to superfine grinding displayed varying levels of antioxidant capacity. The quercetin content (2.18 g 100 g-1) of the wet-grinding bran powder (WGBP) was twice that of the control group, while no rutin was detected. The total flavonoid content (TFC) and total phenolic content (TPC) were significantly different from those of other groups. The DPPH, ˙OH, and ABTS+ removal rates were 60.74%, 86.62%, and 92.98%, respectively, while that of ˙OH was significantly higher than in the other treatment groups. The control group, shear crushed, and airflow comminution bran exhibited no significant differences in TFC, TPC, and oxidation resistance, except for the ability to remove ˙OH. TBB powder obtained via superfine grinding displayed superior taste and functional characteristics, providing a theoretical reference for the processing of this bran.

Characterization and Antimicrobial Activity of Silver Nanoparticles Synthesized with the Peel Extract of Mango.

The green synthesis of silver nanoparticles (AgNPs) from biological waste, as well as their excellent antibacterial properties, is currently attracting significant research attention. This study synthesized AgNPs from different mango peel extract concentrations while investigating their characteristics and antibacterial properties. The results showed that the AgNPs were irregular with rod-like, spherical shapes and were detected in a range of 25 nm to 75 nm. The AgNPs displayed antibacterial activity against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), showing a more significant impact when synthesized with 0.20 g/mL of mango peel extract. Therefore, the antibacterial effect of different diluted AgNP concentrations on the growth kinetic curves of E. coli and S. aureus after synthesis with 0.20 g/mL mango peel extract was analyzed. The results indicated that the AgNP antibacterial activity was higher against S. aureus than against E. coli, while the AgNP IC50 in these two strains was approximately 1.557 mg/mL and 2.335 mg/L, respectively. This research provides new insights regarding the use of postharvest mango byproducts and the potential for developing additional AgNP composite antibacterial materials for fruit and vegetable preservation.