Evaluation of the potential for virus dispersal during hand drying: a comparison of three methods

Aims To use a MS2 bacteriophage model to compare three hand-drying methods, paper towels (PT), a warm air dryer (WAD) and a jet air dryer (JAD), for their potential to disperse viruses and contaminate the immediate environment during use. Methods and Results Participants washed their gloved hands with a suspension of MS2 bacteriophage and hands were dried with one of the three hand-drying devices. The quantity of MS2 present in the areas around each device was determined using a plaque assay. Samples were collected from plates containing the indicator strain, placed at varying heights and distances and also from the air. Over a height range of 0.15-1.65 m, the JAD dispersed an average of >60 and >1300-fold more plaque-forming units (pfu) compared to the WAD and PT (P <0.0001), respectively. The JAD dispersed an average of >20 and >190-fold more pfu in total compared to WAD and PT at all distances tested up to 3 m (P <0.01), respectively. Air samples collected around each device 15 minutes after use indicated that the JAD dispersed an average of >50 and >100-fold more pfu compared to the WAD and PT (P <0.001), respectively. Conclusions Use of the JAD lead to significantly greater and further dispersal of MS2 bacteriophage from artificially contaminated hands when compared to the WAD and PT. Significance and Impact of Study The choice of hand drying device should be considered carefully in areas where infection prevention concerns are paramount, such as healthcare settings and the food industry.

Comparison of virus dispersal and aerosolization by different hand-drying devices

Background World Health Organization and EU hand hygiene guidelines state that if electric hand dryers are used, they should not aerosolize pathogens. Previous studies have investigated the dispersal by different hand-drying devices of chemical indicators, fungi and bacteria on the hands. This study assessed the aerosolization and dispersal of virus on the hands to determine any differences between hand-drying devices in their potential to contaminate other occupants of public washrooms and the washroom environment. Methods A suspension of MS2, an Escherichia coli bacteriophage virus, was used to artificially contaminate the hands of participants prior to using three different hand-drying devices: jet air dryer, warm air dryer, paper towel dispenser. Virus was detected by plaque formation on agar plates layered with the host bacterium. Vertical dispersal of virus was assessed at a fixed distance (0.4 m) and over a range of different heights (0.0 – 1.8 m) from the floor. Horizontal dispersal was assessed at different distances of up to three metres from the hand-drying devices. Virus aerosolization and dispersal was also assessed at different times up to 15 minutes after use by means of air sampling at two distances (0.1 and 1.0 m) and at a distance behind and offset from each of the hand-drying devices. Results Over a range of heights, the jet air dryer was shown to produce over 60 times greater vertical dispersal of virus from the hands than a warm air dryer and over 1300 times greater than paper towels; the maximum being detected between 0.6 and 1.2 metres from the floor. Horizontal dispersal of virus by the jet air dryer was over 20 times greater than a warm air dryer and over 190 times greater than paper towels; virus being detected at distances of up to three metres. Air sampling at three different positions from the hand-drying devices 15 minutes after use showed that the jet air dryer produced over 50-times greater viral contamination of the air than a warm air dryer and over 110-times greater than paper towels. Conclusions Due to their high air speed, jet air dryers aerosolize and disperse more virus over a range of heights, greater distances, and for longer times than other hand drying devices. If hands are inadequately washed, they have a greater potential to contaminate other occupants of a public washroom and the washroom environment. Main messages: Jet air dryers with claimed air speeds of over 600 kph have a greater potential than warm air dryers or paper towels to aerosolize and disperse viruses on the hands of users. The choice of hand-drying device should be carefully considered. Jet air dryers may increase the risk of transmission of human viruses, such as norovirus, particularly if hand washing is inadequate.

Aproveitamento da energia das correntes marítimas

Dissertação para obtenção do grau de Mestre em Engenharia Electrotécnica

Beach sand and the potential for infectious disease transmission: observations and recommendations

Recent studies suggest that sand can serve as a vehicle for exposure of humans to pathogens at beach sites, resulting in increased health risks. Sampling for microorganisms in sand should therefore be considered for inclusion in regulatory programmes aimed at protecting recreational beach users from infectious disease. Here, we review the literature on pathogen levels in beach sand, and their potential for affecting human health. In an effort to provide specific recommendations for sand sampling programmes, we outline published guidelines for beach monitoring programmes, which are currently focused exclusively on measuring microbial levels in water. We also provide background on spatial distribution and temporal characteristics of microbes in sand, as these factors influence sampling programmes. First steps toward establishing a sand sampling programme include identifying appropriate beach sites and use of initial sanitary assessments to refine site selection. A tiered approach is recommended for monitoring. This approach would include the analysis of samples from many sites for faecal indicator organisms and other conventional analytes, while testing for specific pathogens and unconventional indicators is reserved for high-risk sites. Given the diversity of microbes found in sand, studies are urgently needed to identify the most significant aetiological agent of disease and to relate microbial measurements in sand to human health risk.

Climatology of the Iberia coastal low-level wind jet: weather research forecasting model high-resolution results

Coastal low-level jets (CLLJ) are a low-tropospheric wind feature driven by the pressure gradient produced by a sharp contrast between high temperatures over land and lower temperatures over the sea. This contrast between the cold ocean and the warm land in the summer is intensified by the impact of the coastal parallel winds on the ocean generating upwelling currents, sharpening the temperature gradient close to the coast and giving rise to strong baroclinic structures at the coast. During summertime, the Iberian Peninsula is often under the effect of the Azores High and of a thermal low pressure system inland, leading to a seasonal wind, in the west coast, called the Nortada (northerly wind). This study presents a regional climatology of the CLLJ off the west coast of the Iberian Peninsula, based on a 9km resolution downscaling dataset, produced using the Weather Research and Forecasting (WRF) mesoscale model, forced by 19 years of ERA-Interim reanalysis (1989-2007). The simulation results show that the jet hourly frequency of occurrence in the summer is above 30% and decreases to about 10% during spring and autumn. The monthly frequencies of occurrence can reach higher values, around 40% in summer months, and reveal large inter-annual variability in all three seasons. In the summer, at a daily base, the CLLJ is present in almost 70% of the days. The CLLJ wind direction is mostly from north-northeasterly and occurs more persistently in three areas where the interaction of the jet flow with local capes and headlands is more pronounced. The coastal jets in this area occur at heights between 300 and 400 m, and its speed has a mean around 15 m/s, reaching maximum speeds of 25 m/s.

Modelling the Contribution of 40K, 232Th and 226Ra to Radiation Dose and Risk from Airborne Discharges of Coal-Fired Power Plants

Coal contains trace elements and naturally occurring radionuclides such as 40K, 232Th, 238U. When coal is burned, minerals, including most of the radionuclides, do not burn and concentrate in the ash several times in comparison with their content in coal. Usually, a small fraction of the fly ash produced (2-5%) is released into the atmosphere. The activities released depend on many factors (concentration in coal, ash content and inorganic matter of the coal, combustion temperature, ratio between bottom and fly ash, filtering system). Therefore, marked differences should be expected between the by-products produced and the amount of activity discharged (per unit of energy produced) from different coal-fired power plants. In fact, the effects of these releases on the environment due to ground deposition have been received some attention but the results from these studies are not unanimous and cannot be understood as a generic conclusion for all coal-fired power plants. In this study, the dispersion modelling of natural radionuclides was carried out to assess the impact of continuous atmospheric releases from a selected coal plant. The natural radioactivity of the coal and the fly ash were measured and the dispersion was modelled by a Gaussian plume estimating the activity concentration at different heights up to a distance of 20 km in several wind directions. External and internal doses (inhalation and ingestion) and the resulting risk were calculated for the population living within 20 km from the coal plant. In average, the effective dose is lower than the ICRP’s limit and the risk is lower than the U.S. EPA’s limit. Therefore, in this situation, the considered exposure does not pose any risk. However, when considering the dispersion in the prevailing wind direction, these values are significant due to an increase of 232Th and 226Ra concentrations in 75% and 44%, respectively.

Utilização de técnicas de análise fotogramétricas em quebra-mares de taludes

Dissertação de Natureza Científica elaborada no Laboratório Nacional de Engenharia Civil (LNEC) para obtenção do grau de mestre em Engenharia Civil na Área de Especialização de Hidráulica no âmbito do protocolo de cooperação entre o ISEL e o LNEC

Men's Rugby (1981-82)

Back Row: J.B. Owens, Ross Smith (Head Coach), Adam Frost, Derrick Harwood, Dave DeRose, Bill Arniel, Danny Mazor, Alan Ross, Randy McKeller, Pete McDougall, Ray D'Archi, Kelvin Oda, Mark Pelletier, Eric Thompson, Marty Houston, Ken White (Asst. Coach) Front Row: Peter Love, Chris Peskett, Duff Porteous, Bart Ward, Dave Sohmer, Gary Gautier, Ken Murray, Dave Tamowski, Steve Shaughnessy, Jeff Wood Absent: Alfred Esmaily, Luc Gignac, Fred Kovacs, Andrew Norman

The effect of a weighted-vest strength and balance training program on obstructed walking in postmenopausal women

SUMMARY Background: Age related declines in lower extremity strength have been associated with impaired mobility and changes in gait patterns, which increase the likelihood of falls. Since community dwelling adults encounter a wide range of locomotor challenges including uneven and obstmcted walking surfaces, we examined the effect of a strength 11 and balance exercise program on obstructed walking in postmenopausal women. Objectives: This study examined the effect of a weighted-vest strength and balance exercise program on adaptations of the stance leg during obstacle walking in postmenopausal women. Methods: Eighteen women aged 44-62 years who had not engaged in regular resistance training for the past year were recruited from the St. Catharines community to participate in this study. Eleven women volunteered for an aerobic (walking), strength, and balance training program 3 times per week for 12 weeks while 7 women volunteered as controls. Measurements included: force platform dynamic balance measure of the center of pressure (COP) and ground reaction forces (GRFs) in the stance leg while going over obstacles of different heights (0,5, 10,25 and 30 cm); and isokinetic strength measures of knee and ankle extension and flexion. Results: Of the 18 women, who began the trial, 16 completed it. The EX group showed a significant increase of 40% in ankle plantar flexion strength (P < 0.05). However, no improvements in measures of COP or GRFs were observed for either group. Failure to detect any changes in measures of dynamic balance may be due to small sample size. Conclusions: Postmenopausal women experience significant improvements in ankle strength with 12 weeks of a weighted-vest balance and strength training program, however, these changes do not seem to be associated with any improvement in measures of dynamic balance.

Arsenic and germanium determination by hydride generation in the D.C. plasma optical emission spectrometer

Modifications to the commercial hydride generator, manufactured by Spectrametrics, resulted in improved operating procedure and enhancement of the arsenic and germanium signals. Experiments with arsenic(III) and arsenic(V) showed that identical reiults could be produced from both oxidation states. However, since arsenic(V) is reduced more slowly than arsenic(III), peak areas and not peak heights must be measured when the arsine is immediately stripped from the system (approximately 5 seconds reaction). When the reduction is allowed to proceed for 20 seconds before the arsine is stripped, peak heights may be used. For a 200 ng/mL solution, the relative standard deviation is 2.8% for As(III) and 3.8% for As(V). The detection limit for arsenic using the modified system is 0.50 ng/mL. Studies performed on As(V) standards show that the interferences from 1000 mg/L of nickel(II), cobalt(II), iron(III), copper(II), cadmium(II), and zinc(II) can be eliminated with the aid of 5 M Hel and 3% L-cystine. Conditions for the reduction of germanium to the corresponding hydride were investigated. The effect of different concentrations of HCl on the reduction of germanium to the covalent hydride in aqueous media by means of NaBH 4 solutions was assessed. Results show that the best response is accomplished at a pH of 1.7. The use of buffer solutions was similarly characterized. In both cases, results showed that the element is best reduced when the final pH of the solution after reaction is almost neutral. In addition, a more sensitive method, which includes the use of (NH4)2S208' has been developed. A 20% increase in the germanium signal is registered when compared to the signal achieved with Hel alone. Moreover, under these conditions, reduction of germanium could be accomplished, even when the solution's pH is neutral. For a 100 ng/mL germanium standard the rsd is 3%. The detection limit for germanium in 0.05 M Hel medium (pH 1.7) is 0.10 ng/mL and 0.09 ng/mL when ammonium persulphate is used in conjunction with Hel. Interferences from 1000 mg/L of iron(III), copper(II), cobalt(II), nickel(II), cadmium(II), lead(II), mercury(II), aluminum(III), tin(IV), arsenic(III), arsenic(V) and zinc(II) were studied and characterized. In this regard, the use of (NH4)ZS20S and Hel at a pH of 1.7 proved to be a successful mixture in the sbppression of the interferences caused by iron, copper, aluminum, tin, lead, and arsenic. The method was applied to the determination of germanium in cherts and iron ores. In addition, experiments with tin(IV) showed that a 15% increase in the tin signal can be accomplished in the presence of 1 mL of (NH4)2S20S 10% (m/V).

Effects of sample solvent composition and injection volume on chromatographic peak profiles of methyl w- benzimidazolecarbamate and 3-butyl1-2,4-dioxo[1,2-a]-s- triazinobenzimidazole in RP-HPLC

The effects of sample solvent composition and the injection volume, on the chromatographic peak profiles of two carbamate derivatives, methyl 2-benzimidazolecarbamate (MBC) and 3-butyl-2,4-dioxo[1,2-a]-s-triazinobenzimidazole (STB), were studied using reverse phase high performance liquid chromatograph. The study examined the effects of acetonitrile percentage in the sample solvent from 5 to 50%, effects of methanol percentage from 5 to 50%, effects of pH increase from 4.42 to 9.10, and effect of increasing buffer concentration from ° to 0.12M. The effects were studied at constant and increasing injection mass and at four injection volumes of 10, 50, 100 and 200 uL. The study demonstrated that the amount and the type of the organic solvents, the pH, and the buffer strength of the sample solution can have a pronounced effect on the peak heights, peak widths, and retention times of compounds analysed. MBC, which is capable of intramolecular hydrogen bonding and has no tendency to ionize, showed a predictable increase .in band broadening and a decrease in retention times at higher eluting strengths of the sample solvent. STB, which has a tendency to ionize or to strongly interact with the sample solvent, was influenced in various ways by the changes in ths sample solvent composition. The sample solvent effects became more pronounced as the injection volume increased and as the percentage of organic solvent in the sample solution became greater. The peak height increases for STB at increasing buffer concentrations became much more pronounced at higher analyte concentrations. It was shown that the widely accepted procedure of dissolving samples in the mobile phase does not yield the most efficient chromatograms. For that reason samples should be dissolved in the solutions with higher aqueous content than that of the mobile phase whenever possible. The results strongly recommend that all the samples and standards, regardless whether the standards are external or internal, be analysed at a constant sample composition and a constant injection volume.

Investigations into the extraction and the determination of polycyclic aromatic hydrocarbons (PAHs) from water by solid-phase extraction and capillary gas chromatography/ mass spectrometry

Factors affecting the detennination of PAHs by capillary GC/MS were studied. The effect of the initial column temperature and the injection solvent on the peak areas and heights of sixteen PAHs, considered as priority pollutants, USillg crosslinked methyl silicone (DB!) and 5% diphenyl, 94% dimethyl, 1% vinyl polysiloxane (DBS) columns was examined. The possibility of using high boiling point alcohols especially butanol, pentanol, cyclopentanol, and hexanol as injection solvents was investigated. Studies were carried out to optimize the initial column temperature for each of the alcohols. It was found that the optimum initial column temperature is dependent on the solvent employed. The peak areas and heights of the PAHs are enhanced when the initial column temperature is 10-20 c above the boiling point of the solvent using DB5 column, and the same or 10 C above the boiling point of the solvent using DB1 column. Comparing the peak signals of the PAHs using the alcohols, p-xylene, n-octane, and nonane as injection solvents, hexanol gave the greatest peak areas and heights of the PAHs particularly the late-eluted peaks. The detection limits were at low pg levels, ranging from 6.0 pg for fluorene t9 83.6 pg for benzo(a)pyrene. The effect of the initial column temperature on the peak shape and the separation efficiency of the PARs was also studied using DB1 and DB5 columns. Fronting or splitting of the peaks was obseIVed at very low initial column temperature. When high initial column temperature was used, tailing of the peaks appeared. Great difference between DB! and.DB5 columns in the range of the initial column temperature in which symmetrical.peaks of PAHs can be obtained is observed. Wider ranges were shown using DB5 column. Resolution of the closely-eluted PAHs was also affected by the initial column temperature depending on the stationary phase employed. In the case of DB5, only the earlyeluted PAHs were affected; whereas, with DB1, all PAHs were affected. An analytical procedure utilizing solid phase extraction with bonded phase silica (C8) cartridges combined with GC/MS was developed to analyze PAHs in water as an alternative method to those based on the extraction with organic solvent. This simple procedure involved passing a 50 ml of spiked water sample through C8 bonded phase silica cartridges at 10 ml/min, dried by passing a gentle flow of nitrogen at 20 ml/min for 30 sec, and eluting the trapped PAHs with 500 Jll of p-xylene at 0.3 ml/min. The recoveries of PAHs were greater than 80%, with less than 10% relative standard deviations of nine determinations. No major contaminants were present that could interfere with the recognition of PAHs. It was also found that these bonded phase silica cartridges can be re-used for the extraction of PAHs from water.

Meloidogne incognita (nematode) parasitism of Lycopersicon esculentum (tomato) plants : Ethylene action in susceptible and resistant host responses

Involvement of ethylene in the etiology of tomato plants (Lycopersicon esculentum) infected with the root-knot nematode (Meloidogyne incognita) was investigated. Endogenous root concentrations of ethylene were not significantly different in uninfected resistant var. Anahu and susceptible var. Vendor plants. Exposure of resistant plants to high doses of infectious nematode larvae did not affect root ethylene concentrations during the subsequent 30 day period. The possibility that ethylene may be involved in the mechanism of resistance is therefore not supported by these experiments. In no experiments did ethylene concentrations in roots of susceptible plants increase significantly subsequent to ~ incognita infestation. This result is not consistent with the hypothesis in the literature which suggests that increased ethylene production accompanies gall formation. Growth of susceptible tomato plants was affected by ~ incognita infestation such that root weights increased (due to galling), stem heights decreased and top weights increased. The possibility that alterations in stem growth resulted from increased production of 'stress' ethylene is discussed. Growth of resistant plants was unaffected by exposure to high doses of ~ incognita and galls were never detected on the roots of these plants. Root ethane concentrations generally varied in parallel with root ethylene concentrations although ethane concentrations were without exception greater. In 4 of 6 experiments conducted ethane/ethylene ratios increased significantly with time. These results are discussed in the light of published data on the relationship between ethane and ethylene synthesis. The term infested is used throughout this thesis in reference to plants whose root systems had been exposed to nematodes and does not distinguish between the susceptible and resistant response.

The satellite band patterns in the near ultraviolet absorption spectra of isotopic compounds of acetaldehyde

The 3700 A - 3000 A absorption spectra of CH3CHO and its isotopic compounds such as CH3CDO, CD3CHO and CD3CDO were studied in the gas phase at room temperature and low temperatures. The low resolution spectra of the compounds were recorded by a 1.5 m Baush and Lomb grating spectrograph. The high resolution spectra were recorded by a Ebert spectrograph with the Echelle grating and the holographic grating separately. The multiple reflection cells were used to achieve the long path length. The pressure-path length used for the absorption spectrum of CH 3CHO was up to 100 mm Hg )( 91 . 43mo The emission spectrum and the excitation spectrum of CH3CHO were also recorded in this research. The calculated satellite band patterns \vhich were ob-tailied by the method of Lewis were used to compare with the observed near UV absorption spectrum of acetaldehyde. These calculated satellite band patterns belonged to two cases: namely, the barriers-in-phase case and the barriers- out-of-phase case. Each of the calculated patterns corresponded to a stable conformation of acetaldehyde in the excited state . The comparisons showed that the patterns in the observed absorption spectra corresponded to the H-H eclipsed conformations of acetaldehyde in the excited state . The least squares fitting analysis showed that the barrier heights in the excited state were higher than in the ground state. Finally, the isotopic shifts for the isotopic compounds of acetaldehyde were compared to the compounds with the similar deuterium substitution.

The Bee

Newspaper reporting on contemporary events of the wars in North America and Europe including the Battle of Queenston Heights and the death of Isaac Brock. News items include: Page 1: Sheaffe announcement regulating the sale of alcohol in Niagara; Myers announcement asking citizens for the return of American muskets recovered from the battle at Queenston; local notices on business claims and education; want ads for wood, straw, flour and pork for military use; announcement by the Prince Regent in Council putting an embargo on American ships. Page 2: release of American prisoners captured at Queenston; results of a battle by Riga, Latvia the French army under MacDonald against Russia; address of Emperor Alexander I of Russia to troops on declaring war on France; news of the British Navy; mediation between Spain and South American colonies; the security of Canadian properties in wartime; American ships leaving Britain with licenses. Page 3: American ships leaving Britain with licenses; Russian General Platoff’s (Platov) victory over Polish Uhlans; Battle of Salamanca with Lord Wellington. Page 4: report on the Battle of Queenston Heights and the death of Isaac Brock.