Kaile Wang

Non-thermal plasma-activated water inactivation of food-borne pathogen on fresh produce.

Non-thermal plasma has been widely considered to be an effective method for decontamination of foods. Recently, numerous studies report that plasma-activated water (PAW) also has outstanding antibacterial ability. This study presents the first report on the potential of PAW for the inactivation of Staphylococcus aureus (S. aureus) inoculated on strawberries. PAW treatments achieved a reduction of S. aureus ranging from 1.6 to 2.3 log at day-0 storage, while 1.7 to 3.4 log at day-4 storage. The inactivation efficiency depended on the plasma-activated time for PAW generation and PAW-treated time of strawberries inoculated with S. aureus. LIVE/DEAD staining and scanning electron microscopy results confirm that PAW could damage the bacterial cell wall. Moreover, optical emission spectra and oxidation reduction potential results demonstrate the inactivation is mainly attributed to oxidative stress induced by reactive oxygen species in PAW. In addition, no significant change was found in color, firmness and pH of the PAW treated strawberries. Thus, PAW can be a promising alternative to traditional sanitizers applied in the fresh produce industry.

A new organic-organic complex thin film with reproducible electrical bistability properties

Abstract A new organic-organic complex thin film DC-BDCP was prepared by a new method. DC-BDCP was found to possess good electrical bistability properties. The structures and spectral features of DC-BDCP, DC and BDCP thin films were compared by HRSEM, XRD and UV-vis spectra.

Study of a novel C60−2,6‐bis(2,2‐bicyanovinyl)pyridine complex thin film

A novel complex thin film of 2,6‐bis(2,2‐bicyanovinyl)pyridine (BDCP) and C60 has been fabricated by vacuum coevaporation of BDCP and C60 from two different evaporation sources. The C60‐BDCP thin films have shown totally different optical and electronic properties from the films of both the BDCP and C60. Stable and reproducible electric bistable properties have been observed in sandwichlike device Ag/C60‐BDCP/Ag. The films are characterized by several methods including high‐resolution scanning electron microscopy, x‐ray diffraction, UV‐visible absorption and infrared transmission spectroscopy.

Sterilization Efficiency of a Novel Electrochemical Disinfectant against Staphylococcus aureus

Disinfection of hazardous microorganisms that may challenge environmental safety is a crucial issue for economic and public health. Here, we explore the potential of a novel electrochemical disinfectant named plasma activated water (PAW), which was generated by nonthermal plasma, for inactivating Staphylococcus aureus (S. aureus). Meanwhile, the influence of bovine serum albumin (BSA) on the PAW disinfection efficacy was investigated. In the presence of BSA, PAW treatments achieved a reduction of S. aureus ranging from 2.1 to 5.5 Log, when without BSA it reached 7 Log. The sterilization efficacy depended on the PAW treatment time of S. aureus and plasma activation time for PAW generation. The results of electron spin resonance spectra showed the concentrations of hydroxyl radical (OH•) and nitric oxide radical (NO•) in water activated by plasma for 10 min (10-PAW) were higher than those in water activated by plasma for 5 min (5-PAW). Additionally, the physiological analysis of S. aureus demonstrated that the integrity of cell membrane, membrane potential, and intracellular pH homeostasis as well as DNA structure were damaged by PAW, and the molecule structure and chemical bonds of S. aureus were also altered due to PAW. Thus, PAW can be a promising chemical-free and environmentally friendly electrochemical disinfectant for application in the medical and food industries.

Dielectric barrier structure with hollow electrodes and its recoil effect

A dielectric barrier structure with hollow electrodes (HEDBS), in which gas flow oriented parallel to the electric field, was proposed. Results showed that with this structure, air can be effectively ignited, forming atmospheric low temperature plasma, and the proposed HEDBS could achieve much higher electron density (5 × 1015/cm3). It was also found that the flow condition, including outlet diameter and flow rate, played a key role in the evolution of electron density. Optical emission spectroscopy diagnostic results showed that the concentration of reactive species had the same variation trend as the electron density. The simulated distribution of discharge gas flow indicated that the HEDBS had a strong recoil effect on discharge gas, and could efficiently promote generating electron density as well as reactive species.

A new polynitrile π acceptor for electronic switching devices

Abstract A new polynitrile acceptor, 1,1-dicyano-2, 2-(4-dimethylaminophenyl)ethylene (DDME) has been synthesized. A thin film of the charge-transfer complex Ag-DDME has been prepared by a modified conventional vacuum deposition technique. Reproducible bistable electronic switching has been observed in the Ag-DDME thin film sandwiched between two silver electrodes. The films are analyzed by infrared, ultraviolet-visible spectroscopy, high resolution scanning electron microscopy and X-ray diffraction.

Non-thermal plasma for inactivated-vaccine preparation

Vaccines are of great importance in controlling the spread of infectious diseases in poultry farming. The safety and efficacy of vaccines are also essential. To explore the feasibility of a novel technology (non-thermal plasma) in inactivated vaccine preparation, an alternating current atmospheric pressure non-thermal plasma (NTP) jet with Ar/O2/N2 as the operating gas was used to inactivate a Newcastle disease virus (NDV, LaSota) strain and H9N2 avian influenza virus (AIV, A/Chicken/Hebei/WD/98) for vaccine preparation. The results showed that complete inactivation could be achieved with 2 min of NTP treatment for both NDV and AIV. Moreover, a proper NTP treatment time is needed for inactivation of a virus without destruction of the antigenic determinants. Compared to traditional formaldehyde-inactivated vaccine, the vaccine made from NDV treated by NTP for 2 min (NTP-2 min-NDV-vaccine) could induce a higher NDV-specific antibody titer in specific pathogen-free (SPF) chickens, and the results of a chicken challenge experiment showed that NTP-2 min-NDV-vaccine could protect SPF chickens from a lethal NDV challenge. Vaccines made from AIV treated by NTP for 2 min (NTP-2 min-AIV-vaccine) also showed a similar AIV-specific antibody titer compared with traditional AIV vaccines prepared using formaldehyde inactivation. Studies of the morphological changes of the virus, chemical analysis of NDV allantoic fluid and optical emission spectrum analysis of NTP suggested that reactive oxygen species and reactive nitrogen species produced by NTP played an important role in the virus inactivation process. All of these results demonstrated that it could be feasible to use non-thermal NTP as an alternative strategy to prepare inactivated vaccines for Newcastle disease and avian influenza.

Computer-aided analysis with Image J for quantitatively assessing psoriatic lesion area

Body surface area is important in determining the severity of psoriasis. However, objective, reliable, and practical method is still in need for this purpose. We performed a computer image analysis (CIA) of psoriatic area using the image J freeware to determine whether this method could be used for objective evaluation of psoriatic area.

Radiosensitization of oral tongue squamous cell carcinoma by nanosecond pulsed electric fields

Nanosecond pulsed electric fields (nsPEFs) is a novel non-thermal technology to induce a series of medical and biological effects. It has been proven effective in tumor shrinkage, but few studies focus on its radiosensitization in oral tongue squamous cell carcinoma. The purposes of this study were to evaluate the radiosensitization effect of nsPEFs, alone or combined with radiation, on human oral tongue cancer cell line Tca8113 and investigate the potential antitumor mechanism. Tca8113 cell line was tested by MTT assay for cell proliferation, Colony-forming assay for cell radiosensitivity, Flow cytometry assay for cell cycle distribution, Annexin V-FITC assay for cell apoptosis, Mitochondrial potential assay for mitochondrial membrane potential changes and Total Nitric Oxide Assay for NO production1. When treated alone, nsPEFs had a time and strength dependent cytotoxic effect on Tca8113 cells. The dose-enhancement ratio for combined nsPEFs and radiation was markedly increased (SER=1.453±0.038>1). Especially in the combination treatment group, G2/M phase cells (39.73±0.48) were obviously increased compared with control group (13.34±2.61) and radiation group (32.62±1.96). Additionally, NO production increased after nsPEFs treatment. In conclusion, nsPEFs can enhance the radiosensitivity of Tca8113 cells and this may involve the cell cycle arrest at G2/M phase, cell apoptosis induction and NO production in nsPEFs treated system2. These results suggest nsPEFs may provide a novel approach for radiosensitization in oral tongue squamous cell carcinoma.

Inactivation of Ricin Toxin by Nanosecond Pulsed Electric Fields Including Evidences from Cell and Animal Toxicity

Ricin is one of the most toxic and easily produced plant protein toxin extracted from the castor oil plant, and it has been classified as a chemical warfare agent. Here, nanosecond pulsed electric fields (nsPEFs) at 30 kV/cm (pulse durations: 10 ns, 100 ns, and 300 ns) were applied to inactivating ricin up to 4.2 μg/mL. To investigate the efficacy, cells and mice were tested against the ricin treated by the nsPEFs via direct intraperitoneal injection and inhalation exposure. Results showed that nsPEFs treatments can effectively reduce the toxicity of the ricin. Without the nsPEFs treatment, 100% of mice were killed upon the 4 μg ricin injection on the first day, however 40% of the mice survived the ricin treated by the nsPEFs. Compared to injection, inhalation exposure even with higher ricin dose required longer time to observe mice fatality. Pathological observations revealed damages to heart, lung, kidney, and stomach after the ricin exposure, more pronounced for lung and kidney including severe bleeding. Sodium dodecyl sulfate polyacrylamide gel electrophoresis(SDS-PAGE) and circular dichroism (CD) analyses revealed that although the primary structure of ricin was not altered, its secondary structures (beta-sheet and beta-turn) underwent transition upon the nsPEFs treatment.