Brian M. Tande

Rapid Hospital Room Decontamination Using Ultraviolet (UV) Light with a Nanostructured UV-Reflective Wall Coating

We tested the ability of an ultraviolet C (UV-C)-reflective wall coating to reduce the time necessary to decontaminate a room using a UV-C-emitting device (Tru-D SmartUVC). The reflective wall coating provided the following time reductions for decontamination: for methicillin-resistant Staphylococcus aureus, from 25 minutes 13 seconds to 5 minutes 3 seconds ([Formula: see text]), and for Clostridium difficile spores, from 43 minutes 42 seconds to 9 minutes 24 seconds ([Formula: see text]).

Room Decontamination Using an Ultraviolet-C Device with Short Ultraviolet Exposure Time

Results:  UV-C Technology effectively reduces environmental contamination and should be considered when environmental transmission is significant.  The Optimum UV TM device achieved an overall 3.56-log10 reduction for MRSA in 5 minutes and an overall 2.78-log10 reduction for C. difficile spores in 10 minutes in typical patient rooms (not treated with UV reflective wall coating).  When the patient room walls were treated with Lumacept UV reflective wall coating, the Optimum UV achieved an overall 4.5-log10 reduction for MRSA in 5 minutes and an overall 3.05-log10 reduction for C. difficile spores in 10 minutes.  The use of UV reflective wall coating (Lumacept) significantly increased the overall Log reduction obtained, primarily by increasing the UV-C irradiation and Log reduction for indirect surfaces.

AROMATIZATION OF PROPYLENE OVER HZSM-5: A DESIGN OF EXPERIMENTS (DOE) APPROACH

Aromatization of propylene was performed in a continuous reactor over HZSM-5 catalysts. A full-factorial design of experiments (DOE) methodology identified the effects of temperature (400°–500°C), Si:Al ratio (50–80), propylene feed concentration (8.9–12.5 mol.%), and catalyst amount (0.2–1.0 g) on propylene conversion as well as the yields of benzene, toluene, p-xylene, o-xylene (BTX), and total BTX. The Si:Al ratio and amount of the HZSM-5 catalyst influenced all of the responses, while temperature affected all the responses except the yield of p-xylene. An increase in feed concentration significantly increased the yields of benzene, toluene, and total BTX. An interaction between propylene feed concentration and catalyst amount influenced the yields of benzene, toluene, and total BTX. This interaction indicated that a higher feed concentration promotes aromatization at higher catalyst concentrations. By contrast, the interaction of Si:Al ratio with propylene feed concentration was found significant for p-xylene and o-xylene yields, but not for benzene and toluene, suggesting that xylenes are synthesized on different sites than those for benzene and toluene. These interaction effects demonstrate how the use of DOE can uncover significant information generally missed using traditional experimental strategies.

Recovery of CO2 from Monoethanolamine using a Membrane Contactor

The technical feasibility of using polymeric membranes to recover CO2 from saturated monoethanolamine was investigated. A lab-scale system was built to study the performance of several common polymeric porous membranes for the recovery of CO2 from saturated aqueous MEA solution (15% wt) using a thermal swing process. Compositional, structural, and surface morphological characterization was carried out on the membranes before and after this process. The results showed polypropylene and polytetrafluoroethylene porous membranes outperformed polyester, polyamide, polyvinylidene fluoride, polysulfone, and cellulose acetate. The major component of mass transfer resistance was found to be the liquid boundary layer at the surface of the membrane. Membrane wetting and fouling were found to significantly deteriorate membrane performance.

Extraction of Fatty Acids from Noncatalytically Cracked Triacylglycerides with Water and Aqueous Sodium Hydroxide

A study was performed to determine the effectiveness of extracting short-chain fatty acids (SCFAs) from noncatalytically cracked canola oil using neutral and basic aqueous solutions. A detailed quantitative analysis was performed to determine the composition of the cracking reactor organic liquid product (OLP) before and after extraction. We have demonstrated that water alone can be used to completely extract C2 and C3 monocarboxylic acids, while partially extracting acids up to C6. The degree of extraction can be slightly increased by increasing temperature and, for some acids, by using multiple extraction stages. A basic solution (1 M NaOH) was found to extract a wider range of acids—up to C8—and this was independent of the temperature or number of stages. While this method was not capable of reducing the acid number of the OLP to within the specifications for fuel, it could be used to extract a narrow range (C2 to C5) of biobased carboxylic acids. As such, this method could serve as one step in a process to produce biobased carboxylic acids, replacing acids currently produced from non-renewable sources.

Extraction of Fatty Acids from Noncatalytically Cracked Triacylglycerides Using Aqueous Amines

It has been reported that a basic aqueous solution was effective in extracting short chain C2–C6 fatty acids from noncatalytically cracked triacylglyceride oils. However, the extraction efficiency was not optimal over the entire range (C2–C12) of acids present in the cracking reactor organic liquid product (OLP). Therefore, an additional study was performed to explore the efficiency of solvent extraction using aqueous amines for this application. Based on the screening of several amines, two tertiary amines, trimethyl amine (TMA), and dimethyl ethanolamine (DMEA), were selected and evaluated. The extraction conditions were optimized with respect to several factors: temperature, amine concentration, and the amine-to-OLPratio (amine/OLP). Under optimal conditions, both TMA and DMEA were effective in extracting a wide range of organic acids, with TMA removing 93% of total acids and DMEA removing 100% of total acids. The amine/OLP was found to be a significant factor, as was the concentration of the amine solution. Temperature was not found to be a significant factor over the range studied. These results provide a basis for the development of a scalable, continuous process to produce a variety of C2–C12 fatty acids from biological sources.

Does coating all room surfaces with an ultraviolet C light-nanoreflective coating improve decontamination compared with coating only the walls?

Decontamination Compared with Coating Only the Walls? Author(s): William A. Rutala, PhD, MPH; David J. Weber, MD, MPH; Maria F. Gergen, MT(ASCP); Brian M. Tande, PhD; Emily E. Sickbert-Bennett, PhD, MS Source: Infection Control and Hospital Epidemiology, Vol. 35, No. 3 (March 2014), pp. 323-325 Published by: The University of Chicago Press on behalf of The Society for Healthcare Epidemiology of America Stable URL: http://www.jstor.org/stable/10.1086/675291 . Accessed: 28/06/2014 17:54

Determination of Celecoxib in human plasma using liquid chromatography with high resolution time of flight-mass spectrometry

A sensitive method for the determination of Celecoxib (CXB) in human plasma samples was developed using liquid chromatography coupled to electrospray ionization and time of flight mass spectrometry (LC-ESI-TOF-MS). A full factorial design of experiments (FF-DOE) methodology was applied to optimize the ESI conditions for CXB determination and also to predict the effects of interactions of multiple parameters affecting ionization (i.e., capillary voltage, fragmentor voltage, electrolyte and electrolyte concentration). The optimum ionization voltages were 4500V and 220V for capillary and fragmentor, respectively. Even though the highest ESI efficiency was obtained without electrolytes, the addition of 1.0mM ammonium acetate was shown to be essential to buffer the matrix effect and ensure a consistent response. In contrast to previous studies, deuterated CXB was used as a recovery (surrogate) standard, which enabled the correction of CXB loss during sample preparation. The extraction recovery using solid phase extraction was 87-98%. The instrumental limit of detection of CXB (LOD), 0.33ng/mL, and matrix affected LOD, 0.55ng/mL, were similar and comparable to the previously reported LC-MS/MS LODs. This method was employed to determine CXB concentrations in human plasma samples. Upon administration of 400mg CXB to the healthy women, the concentrations found in the plasma were 440-3300ng/mL. The inter-day repeatability was less than 4% RSD.

Purification of natural gas using thermally rearranged polybenzoxazole and polyimide membranes – a review: part 1

This feature article – published in two parts – focuses on the evolution of polyimide as a gas separation membrane, its subsequent transformation into polybenzoxazole and various studies done to optimise the separation ability of polybenzoxazole. The first instalment, which appears here, provides theory and background, including details of the solution-diffusion model and a description of fractional free volume. It also discusses the limitations of membrane separation and the permeability/selectivity trade-off, and covers physical ageing, plasticisation, polyimide synthesis, design of polyimide, thermal annealing and cross-linking.

Improving the effectiveness of ultraviolet germicidal irradiation through reflective wall coatings: Experimental and modeling based assessments

Experimental and modeling based assessments of employing reflective wall coatings towards improving the effectiveness of ultraviolet germicidal irradiation in unoccupied hospital rooms were carried out. Measurements of incident radiative fluxes on different surfaces were made in a control room as well as a room whose walls were painted with a nanostructured UV-C reflective wall coating. Employing the reflective paint resulted in up to a 20% increase in the incident radiative fluxes on some surfaces that were directly exposed to the radiation and nearly a 10-fold increase on surfaces that were not directly exposed. Spatially and directionally well-resolved simulations of radiative transfer within the rooms were carried out employing the finite volume radiation model. The measured enhancement in radiative fluxes predicted numerically agreed in general with experimental observations. The volume-averaged incident radiation increased by 60% in the presence of UV reflective walls. Ray effects or the preferential streaming of radiation in the numerical calculations was more pronounced in the control room and was minimized by increasing the angular resolution of the calculations even further. However in the room with UV reflective walls, the diffuse reflections caused the intensity distributions to become more isotropic and minimized the impacts of ray effects.