Non-UV germicidal activity of fresh TiO_2 and Ag/TiO_2

Fresh TiO2 was found to possess a strong germicidal activity even without UV irradiation. Live Yeast （Saccharomyces cerevisiae） cells in contact with fresh TiO2 were found deformed and dead after 15min contact. The cause of germicidal activity was discussed from the observed cell deformation, lysis and increased absorption at 1680 cm^-1 in FT-IR spectra of the affected cells, which proved the oxidizing effect of fresh TiO2 to cells. The deformation caused by the stretching of cell wail and pressure built-up inside the cell, led to cell burst and release of intracellular materials. The degree of cell deformation was found positively related with the wetting property of TiO2. Cells are negatively charged, for Gram-negative cell （thinner ceil wail）, a higher germicidal effect was observed than Gram-positive cells. The germicidal effect of TiO2 gradually decreased after exposure to air at room temperature, as the wetting property decreased. This kind of germicidal activity was more effective compared to other germicidal process such as UVA/TiO2 or Ag＋. This shed light on designing new germicidal material either maintained by visible light irradiation, or by oxidation effect generated by reactive oxygen species.

Non-UV based germicidal activity of metal-doped TiO_2 coating on solid surfaces

A stain-based screening method was developed to screen different catalyst coatings for their germicidal activity. A Baclight dead/live bacteria viability kit （invitrogen, molecular probes） was used for staining the cell. The screening was carried out following a standard procedure. This included loading cell suspension to solid surface and maintaining contact for 30 min, then staining with a mixture containing dyes. The stained cells were observed using an epifluorescent microscope and photographed with a CCD camera under UV. Metal-doped TiO2 coatings on AI plates were prepared and tested for non-UV germicidal activity without using UV. It was tested using model microorganisms such as Bakers Yeast （Saccharomyces cerevisiae）, Bacillus subtilis, Pseudomonas putida, and Escherichia coli. On the basis of the germicidal activity of catalyst and the degree of damage caused to the cells, the stained cells may appear green （viable）, green with red or yellow nuclei and yellow （compromised） or red （nonviable）. According to their stained color, cells were counted to calculate the percentage of dead, live, and compromised cells. Compromised cells are cells that grow very slowly after reculturing indicating a degree of reversible cell damage. Screening the germicidal activity using this staining method is accurate and efficient, and requires less time than the culture-based method. A modification to the procedure for measuring germicidal activity of rough surfaces or fibrous coatings was developed. Both TiO2 and metal-doped TiO2 （Ag, Pt, Au, Cu） possess non-UV based germicidal activity. The germicidal activity of TiO2 was found to be related with its wetting property and can be improved by UV irradiation before testing. It is not greatly affected by contact time, indicating a fast acting germicidal activity.

Identification of Strawberry Anthracnose Pathogens and Screening of Germicides

[Objective] This study aimed to identify strawberry anthracnose pathogens and screen appropriate germicides. [Method] Strawberry anthracnose pathogens in Jurong City of Jiangsu Province were isolated and identified. The toxicities of sever-al germicides to Col etotrichum fragariae were determined with indoor mycelial growth inhibition assay. Field control test was preformed to further verify the control efficacy of germicides. [Result] The isolated strawberry anthracnose pathogenic strains were identified as C. gloeosporioide from genus Col etotrichum of subphylum Deuteromycotina. Prochloraz, pyrazole Kresoxim and hexaconazole al exhibited good indoor control effects; 25% pyrazole Kresoxim EC2000-fold solution, 24% azoxys-trobin＆#183;hexaconazole （azoxystrobin∶hexaconazole=1∶2） SC1500-fold solution and 25%prochloraz EC1000-fold solution al exhibited significant field control efficacy. [Con-clusion] The study provides reference for the alternate use of germicides in actual production.

Studies of non-metallic organic disinfectants on inactivation of avian influenza viruses

Six different kinds of non-metallic or organic disinfectants were obtained in this research study including “Neutral Electrolyzed Water”, “M22” organic disinfectant solution, Superoxy Food Wash disinfectant, Hydrogen Peroxide, Clorox Germicidal Bleach and Clidox-S. The effectiveness of these disinfectants was studied against various subtypes of avian influenza virus (AIV). The virus-disinfectant mixtures were prepared in serial dilutions of each disinfectant with a constant virus titer and incubated at ambient temperature in different time intervals for virus inactivation. The virus inactivation results were determined by virus recovery in embryonating chicken eggs. Among the six different kinds of nonmetallic disinfectants obtained for this research project, Neutral Electrolyzed Water, “M22” solution, Clorox Germicidal Bleach and Clidox-S were effectively inactivated AIV with appropriate working dilutions and reaction times. Superoxy Food Wash disinfectant and Hydrogen Peroxide were found having limited effect on virus inactivation with extended exposure times of more than 2 hours. These research findings provide scientific data to poultry industry with guidelines to select and use non-metallic organic disinfectants for poultry flock sanitation and disinfection to effectively prevent and control of avian influenza outbreaks.

Novel Air Purification System for Installation in Air Handling Units： Development, Assembly and Experimental Analysis

Nowadays, people pass 90% of their time in closed spaces, therefore, an increasing care in the creation and upkeep of healthier environments as a personal and as professional level become a major issue. The present project has as goal the verification and optimization of the implicit need of an OCRAMclima~ AHU （air handling units） in IAQ （indoor air quality） and its effectiveness in treatment and/or air purification, having as basis the legal national and European requirements for IAQ. This work was based on the study of the state of the art of the techniques in air purification and in the evaluation of their performance, culminating in the production of the prototype OCRAMclima~ NPS （nano purifying system）. The purifying phenomena involved are UVGI （ultraviolet germicidal irradiation） and catalytic ionization of air. The performance test was accomplished in a closed loop circuit, which results, obtained by an independent IAQ analyst, were satisfactory, indicating the viability of application of this system to indoor air disinfection. The outcome revealed that the conjugating of both phenomena, the air sterilizing by UV and catalytic ionization, is efficient when used for air purification, mainly for volatile organic compounds and bioaerosols.

High-level disinfection of gastrointestinal endoscope reprocessing

High level disinfection(HLD) of the gastrointestinal(GI)endoscope is not simply a slogan, but rather is a form of experimental monitoring-based medicine. By definition,GI endoscopy is a semicritical medical device. Hence,such medical devices require major quality assurance for disinfection. And because many of these items are temperature sensitive, low-temperature chemical methods, such as liquid chemical germicide, must be used rather than steam sterilization. In summarizing guidelines for infection prevention and control for GI endoscopy, there are three important steps that must be highlighted: manual washing, HLD with automated endoscope reprocessor, and drying. Strict adherence to current guidelines is required because compared to any other medical device, the GI endoscope is associated with more outbreaks linked to inadequate cleaning or disinfecting during HLD. Both experimental evaluation on the surveillance bacterial cultures and in-use clinical results have shown that, the monitoring of the stringent processes to prevent and control infection is an essential component of the broader strategy to ensure the delivery of safe endoscopy services, because endoscope reprocessing is a multistep procedure involving numerous factors that can interfere with its efficacy. Based on our years of experience in the surveillance of culture monitoring of endoscopic reprocessing, we aim in this study to carefully describe what details require attention in the GI endoscopy disinfection and to share our experience so that patients can be provided with high quality and safe medical practices. Quality management encompasses all aspects of pre- and postprocedural care including the efficiency of the endoscopy unit and reprocessing area, as well as the endoscopic procedure itself.

Structure of Gadolinium Complex with Acetylene Dicarboxylate(ADC)

Gd2 （OOCC2COO）3（H2O）6]·2H2O,Mr=794.8,triclinic.P1,a=8.254（2）,b=9. 605（2）.c=9.066（2）,α=95. 38（2）,β=115.82（2）,γ=110.39（2）°,V=519.8（2）,Z=1,Dx=2.54 g/cm3,λ（MoKα） =0.71069,μ=66.3 cm-1,F（000）=376,T=294 K,R=0.035 for 2694 observed reflections.The Gd￣3+ ion is 9-coordinated,bound to six oxygen atoms from carboxylate groups and to three water molecules to form a monocapped square antiprism coordination polyhedron.There is one lattice water molecule in an asymmetric unit.