Antifungal Activity and Mechanism of 4-Propylphenol Against Fusarium graminearum, Agent of Wheat Scab, and Its Potential Application.

Fusarium head blight (FHB), caused by Fusarium graminearum, is a predominant disease of wheat. Due to the lack of disease-resistant germplasm, chemical control is an important means to control wheat scab. Volatile substances produced in near-isogenic wheat lines were detected after inoculation with F. graminearum, and 4-propylphenol, which appears in FHB-resistant lines, was identified. In vitro and in vivo antifungal activity tests demonstrate that 4-propylphenol effectively inhibits the mycelial growth of F. graminearum. Metabolomics analysis showed changes in glutathione metabolism, indicating that 4-propylphenol triggered reactive oxygen species (ROS) stress. This was consistent with the increasing ROS levels in Fusarium cells treated with 4-propylphenol. Further results demonstrated that excessive accumulation of ROS induced DNA and cell membrane damage in the mycelium. Moreover, 4-propylphenol showed different degrees of inhibition against other soil-borne pathogens (fungi and oomycetes). These findings illustrated that 4-propylphenol has broad spectrum and high antifungal activity and should be considered for use as an ecological fungicide.

Injectable macro-porous chitosan/polyethylene glycol-silicotungstic acid double-network hydrogels based on "smashed gels recombination" strategy for cartilage tissue engineering.

The lack of interconnected macro-porous structure of most injectable hydrogels lead to poor cell and tissue infiltration. Herein, we present the fabrication of injectable macro-porous hydrogels based on "smashed gels recombination" strategy. Chitosan/polyethylene glycol-silicotungstic acid (CS/PEG-SiW) double-network hydrogels were prepared via dual dynamic interactions. The bulk CS/PEG-SiW hydrogels were then smashed into micro-hydrogels with average sizes ranging from 47.6 to 63.8 µm by mechanical fragmentation. The CS/PEG-SiW micro-hydrogels could be continuously injected and rapidly recombined into a stable porous hydrogel based on the dual dynamic interactions between micro-hydrogels. The average pore size of the recombined porous CS/PEG-SiW hydrogels ranged from 52 to 184 µm. The storage modulus, compress modulus and maximum compressive strain of the recombined porous CS/PEG-SiW1.0 hydrogels reached about 47.2 %, 28.2 % and 127.6 % of the values for their corresponding bulk hydrogels, respectively. The recombined porous hydrogels were cytocompatible and could effectively support proliferation and chondrogenic differentiation of bone marrow mesenchymal stem cells (BMSCs). In a rat cartilage defect model, recombined porous CS/PEG-SiW hydrogels could promote cartilage regeneration. Hematoxylin and eosin (H&E), Safranin-O/Fast green and immunohistochemical staining confirmed the accumulation of glycosaminoglycans (GAG) and type II collagen (Col II) in regenerated cartilage.

Application of Polysaccharide Biopolymer in Petroleum Recovery.

Polysaccharide biopolymers are biomacromolecules derived from renewable resources with versatile functions including thickening, crosslinking, adsorption, etc. Possessing high efficiency and low cost, they have brought wide applications in all phases of petroleum recovery, from well drilling to wastewater treatment. The biopolymers are generally utilized as additives of fluids or plugging agents, to correct the fluid properties that affect the performance and cost of petroleum recovery. This review focuses on both the characteristics of biopolymers and their utilization in the petroleum recovery process. Research on the synthesis and characterization of polymers, as well as controlling their structures through modification, aims to develop novel recipes of biopolymer treatment with new application realms. The influences of biopolymer in many petroleum recovery cases were also evaluated to permit establishing the correlations between their physicochemical properties and performances. As their performance is heavily affected by the local environment, screening and testing polymers under controlled conditions is the necessary step to guarantee the efficiency and safety of biopolymer treatments.

An experimental investigation of underwater spread of oil spill in a shear flow.

The time taken for spilt oil to appear firstly at the sea surface and its location are two key issues for emergency response. The underwater spread of oil spill in a shear flow was studied experimentally in a re-circulating water channel. The high speed imaging technology was employed to record the whole transport process of oil spilt from a leak of a submarine pipe to the surface. Based on the experimental results, three underwater transport types are identified, which are single droplet pattern (model A), linear chain pattern (model B) and oil plume pattern (model C), respectively. The pressure difference inside and outside of the leak determines the underwater transport pattern. For single droplet pattern, the transport of oil droplet has two successive stage, namely the accumulation stage and the buoyant droplet stage. When it comes to linear chain pattern, the first stage changes to be the initial jet stage. Besides the initial jet stage and the buoyant droplet stage, oil plume pattern has an intermediate transition stage, namely the plume development stage. During the whole floating process, the pressure difference dominates the initial stage, while droplet buoyancy is the driven force in the rest. The required time for oil droplets to reach the surface is increased with the decreasing of the initial momentum and the increasing of the shear flow velocity. In the buoyance dominated stage, the floating rate of oil droplets is basically unchanged and the horizontal migration rate is similar with the shear flow velocity. Both the break-up and coalescence of oil droplets have two forms, which are single droplet splitting and droplet-column separation for break-up form and turbulence merging and pursuit merging for coalescence form, respectively.

Undergraduate student nurses' lived experiences of anxiety during their first clinical practicum: A phenomenological study.

BACKGROUND: The Fundamental Nursing clinical practicum is an essential module for nursing students. Some feel stress or anxiety about attending this first placement; however, evidence demonstrates that it is rare to explore the feelings of anxiety felt by the nursing students concerning their first clinical practicum. OBJECTIVE: This study was designed to explore student nurses' experiences of anxiety felt regarding their initial clinical practicum while studying for their University degree. DESIGN: A phenomenological approach was used. SETTINGS: A university in Southern Taiwan. PARTICIPANTS: A purposive sampling of fifteen student nurses with anxiety reactions who had completed their first clinical practicum. METHODS: Data were collected using a semi-structured guide and deep interview. Data were analyzed using Colaizzi's seven-step phenomenological method. RESULTS: Three themes surfaced in the findings. The first theme was anxiety around their first clinical practicum, which stirred up anxiety about: self-doubt, worry and fear; difficulty coping with the learning process; worry hampered establishing therapeutic relationships with patients; the progress of the patients' illness could not be predicted; and anxiety felt about lecturer-student interactions. The second theme was three phases of anxiety reactions, which included increasing anxiety before clinical practicum; exacerbated anxiety during clinical practicum, and relief of anxiety after clinical practicum. The third theme was coping behaviors. This comprised: self-reflection in preparation for clinical practicum; finding ways to release emotions; distractions from the anxiety; and, also facing their difficulties head-on. CONCLUSION: The findings could help raise the awareness of lecturers and students by understanding student nurses' anxiety experiences and facilitating a healthy preparation for their initial clinical practicum, consequently proactively helping reduce potential anxiety experiences.