Satisfaction and convenience of using terpenoid-impregnated eyelid wipes and teaching method in people without blepharitis.

Science.gov (United States)

Qiu, Tian Yu; Yeo, Sharon; Tong, Louis

2018-01-01

Demodex infestations cause blepharitis and are difficult to treat. Recently, a new type of eyelid wipes with terpenoids has been found effective. We aim to evaluate patient satisfaction after short-term use and compare two teaching modalities on the techniques of use. Eligible participants were taught to use eyelid wipes (Cliradex ® ) by either live or online video demonstration based on random allocation. Participants used the wipes twice daily for a week. All participants had prior evaluation of socioeconomic status, dry eye symptoms, and meibomian gland features. After 1 week, competence of use was assessed by participants showing their technique to the investigator, and a questionnaire on comfort, ease, and convenience of use was administered. Higher scores indicate greater satisfaction, and these levels are compared among the two teaching modalities using chi square. A total of 50 participants were recruited, with a mean age of 42±16 years, and 88% of the participants were females. Overall, median comfort level was 4.0 (range: 1-6), ease level was 5.0 (3-6), and convenience level was 5.0 (2-6). Median stinging was 2.0 (1-4), which corresponded to some but mild stinging. The median competence level was 4.0 (2-4), which corresponded to excellent competence. These satisfactory levels (ease, comfort, and convenience) experienced were not significantly associated with different socioeconomic indicators, that is, housing type, income, highest education level, and were not different between teaching methods ( p >0.05). Short-term use of Cliradex eyelid wipes seems to be acceptable to most people. The teaching instructions before using these wipes were equally effective - whether live or online video demonstration was used.

Valuation of cloths for decontamination by wiping

International Nuclear Information System (INIS)

Rankin, W.N.; Reif, D.J.; Fink, S.D.; Luckenbach, R.L.

1990-01-01

Treated polyester cloth was evaluated in laboratory-scale and larger-scale tests as an alternative to atomic wipes and cotton cloth for use in decontamination by wiping. The advantages of the treated polyester are as follows: Does not react with nitric acid to form unstable product, More fire resistant, Less volume of radioactive waste generated (versus atomic wipes), and Product can be recovered by soaking the polyester cloths in nitric acid. Results are that even though treated polyester wiping cloths are slightly less effective than atomic wipes and cotton cloth, its many other benefits greatly outweigh this slight disadvantage. 1 ref., 5 figs

Study on the wiping gas jet in continuous galvanizing line

Science.gov (United States)

Kweon, Yong-Hun; Kim, Heuy-Dong

2011-09-01

In the continuous hot-dip galvanizing process, the gas-jet wiping is used to control the coating thickness of moving steel strip. The high speed gas-jet discharged from the nozzle slot impinges on the strip, and at this moment, wipes the liquid coating layer dragged by a moving strip. The coating thickness is generally influenced on the flow characteristics of wiping gas-jet such as the impinging pressure distribution, pressure gradient and shear stress distribution on the surface of strip. The flow characteristics of wiping gas-jet mentioned above depends upon considerably both the process operating conditions such as the nozzle pressure, nozzle-to-strip distance and line speed, and the geometry of gas-jet wiping apparatus such as the height of nozzle slot. In the present study, the effect of the geometry of nozzle on the coating thickness is investigated with the help of a computational fluid dynamics method. The height of nozzle slot is varied in the range of 0.6mm to 1.7mm. A finite volume method (FVM) is employed to solve two-dimensional, steady, compressible Navier-Stokes equations. Based upon the results obtained, the effect of the height of nozzle slot in the gas-jet wiping process is discussed in detail. The computational results show that for a given standoff distance between the nozzle to the strip, the effective height of nozzle slot exists in achieving thinner coating thickness.

Allergenic Ingredients in Personal Hygiene Wet Wipes.

Science.gov (United States)

Aschenbeck, Kelly A; Warshaw, Erin M

Wet wipes are a significant allergen source for anogenital allergic contact dermatitis. The aim of the study was to calculate the frequency of potentially allergenic ingredients in personal hygiene wet wipes. Ingredient lists from brand name and generic personal hygiene wet wipes from 4 large retailers were compiled. In the 54 personal hygiene wet wipes evaluated, a total of 132 ingredients were identified (average of 11.9 ingredients per wipe). The most common ingredients were Aloe barbadensis (77.8%), citric acid (77.8%), fragrance (72.2%), sorbic acid derivatives (63.0%), tocopherol derivatives (63.0%), glycerin (59.3%), phenoxyethanol (55.6%), disodium cocoamphodiacetate (53.7%), disodium ethylenediaminetetraacetic acid (EDTA) (42.6%), propylene glycol (42.6%), iodopropynyl butylcarbamate (40.7%), chamomile extracts (38.9%), sodium benzoate (35.2%), bronopol (22.2%), sodium citrate (22.2%), lanolin derivatives (20.4%), parabens (20.4%), polyethylene glycol derivatives (18.5%), disodium phosphate (16.7%), dimethylol dimethyl hydantoin (DMDM) (14.8%), and cocamidopropyl propylene glycol (PG)-dimonium chloride phosphate (11.1%). Of note, methylisothiazolinone (5.6%) was uncommon; methylchloroisothiazolinone was not identified in the personal hygiene wet wipes examined. There are many potential allergens in personal hygiene wet wipes, especially fragrance and preservatives.

In vitro prediction of in vivo skin damage associated with the wiping of dry tissue against skin.

Science.gov (United States)

Koenig, David W; Dvoracek, Barb; Vongsa, Rebecca

2013-02-01

The ideal gentle cleansing product is one that effectively removes soils while minimizing damage to the skin. Thus, measuring physical abrasion caused by cleansing tissues is critical to the continued development of gentle cleansing products. Current analysis of cleansing materials for skin gentleness is time consuming and requires expensive human subject testing. This report describes the development of a rapid and inexpensive bench assay for the assessment of skin abrasion caused by wiping. Coefficient of friction (COF) evaluations using bench methods were compared with results from clinical studies of repeated wiping and with confocal visualizations of excised skin. A Monitor/Slip and Friction instrument (model 32-06; TMI, Amityville, NY, USA) was used to measure tissue friction on simulated skin (Vitro-Skin, N19-5X; IMS, Milford, CT, USA). Clinical data from a 4-day repetitive forearm wiping study measuring transepidermal water loss (TEWL) in 30 subjects was compared with results from the bench top assay. In addition, excised skin samples were also treated using the COF bench assay and examined using confocal microscopy to visualize stratum corneum damage caused by wiping. Using the bench COF assay, we were able to distinguish between bath tissue codes by comparing average static friction value (ASFV) for the test codes, where lower ASFV indicated less abrasive tissue. The ASFV followed the same gentleness trend observed in the clinical study. Confocal microscopy of excised skin wiped with the same materials indicated stratum corneum damage consistent with the bench COF and clinical TEWL observations. We observed significant correlation between bench and clinical methods for measuring skin damage caused by wiping of skin with tissue. The bench method will facilitate rapid and inexpensive skin gentleness assessment of cleansing materials. © 2012 John Wiley & Sons A/S.

Measuring PM2.5, Ultrafine Particles, Nicotine Air and Wipe Samples Following the Use of Electronic Cigarettes.

Science.gov (United States)

Melstrom, Paul; Koszowski, Bartosz; Thanner, Meridith Hill; Hoh, Eunha; King, Brian; Bunnell, Rebecca; McAfee, Tim

2017-09-01

Few studies have examined the extent of inhalation or dermal contact among bystanders following short-term, secondhand e-cigarette exposure. Measure PM2.5 (particles e-cigarette exposure. E-cigarettes were used ad libitum by three experienced users for 2 hours during two separate sessions (disposable e-cigarettes, then tank-style e-cigarettes, or "tanks") in a 1858 ft3 room. We recorded: uncorrected PM2.5 (using SidePak); UF (using P-Trak); air nicotine concentrations (using air samplers; SKC XAD-4 canisters); ambient air exchange rate (using an air capture hood). Wipe samples were taken by wiping 100 cm2 room surfaces pre- and post- both sessions, and clean cloth wipes were worn during the exposure and collected at the end. Uncorrected PM2.5 and UF were higher (p e-cigarette use can produce: elevated PM2.5; elevated UF; nicotine in the air; and accumulation of nicotine on surfaces and clothing. Short-term indoor e-cigarette use produced accumulation of nicotine on surfaces and clothing, which could lead to dermal exposure to nicotine. Short-term e-cigarette use produced elevated PM2.5 and ultrafine particles, which could lead to secondhand inhalation of these particles and any chemicals associated with them by bystanders. We measured significant differences in PM2.5 and ultrafine particles between disposable e-cigarettes and tank-style e-cigarettes, suggesting a difference in the exposure profiles of e-cigarette products. Published by Oxford University Press on behalf of Society for Research on Nicotine and Tobacco 2017. This work is written by (a) US Government employee(s) and is in the public domain in the US.

Validation and comparison of two sampling methods to assess dermal exposure to drilling fluids and crude oil.

Science.gov (United States)

Galea, Karen S; McGonagle, Carolyn; Sleeuwenhoek, Anne; Todd, David; Jiménez, Araceli Sánchez

2014-06-01

Dermal exposure to drilling fluids and crude oil is an exposure route of concern. However, there have been no published studies describing sampling methods or reporting dermal exposure measurements. We describe a study that aimed to evaluate a wipe sampling method to assess dermal exposure to an oil-based drilling fluid and crude oil, as well as to investigate the feasibility of using an interception cotton glove sampler for exposure on the hands/wrists. A direct comparison of the wipe and interception methods was also completed using pigs' trotters as a surrogate for human skin and a direct surface contact exposure scenario. Overall, acceptable recovery and sampling efficiencies were reported for both methods, and both methods had satisfactory storage stability at 1 and 7 days, although there appeared to be some loss over 14 days. The methods' comparison study revealed significantly higher removal of both fluids from the metal surface with the glove samples compared with the wipe samples (on average 2.5 times higher). Both evaluated sampling methods were found to be suitable for assessing dermal exposure to oil-based drilling fluids and crude oil; however, the comparison study clearly illustrates that glove samplers may overestimate the amount of fluid transferred to the skin. Further comparison of the two dermal sampling methods using additional exposure situations such as immersion or deposition, as well as a field evaluation, is warranted to confirm their appropriateness and suitability in the working environment. © The Author 2014. Published by Oxford University Press on behalf of the British Occupational Hygiene Society.

Simultaneous Determination of Alkoxyalcohols in Wet Wipes Using Static Headspace Gas Chromatography and Mass Spectrometry

Energy Technology Data Exchange (ETDEWEB)

Lee, So Jin; Pyo, Hee Soo; Chung, Bong Chul; Lee, Jeon Gae [KIST, Seoul (Korea, Republic of); Kim, Hai Dong [Kyung Hee University, Seoul (Korea, Republic of)

2014-09-15

Alkoxyalcohols are used as solvents or preservatives in various consumer products such as wet wipes. The metabolites of alkoxyalcohols are known to be chronically toxic and carcinogenic to animals. Thus, an analytical method is needed to monitor alkoxyalcohols in wet wipes. The aim of this study was to develop a simultaneous analytical method for 14 alkoxyalcohols using headspace gas chromatography coupled with mass spectrometry to analyze the wet wipes. This method was developed by comparing with various headspace extraction parameters. The linear calibration curves were obtained for the method (r2 > 0.995). The limit of detection of alkoxyalcohols ranged from 2 to 200 ng mL-1. The precision of the determinative method was less than 18.20% coefficient of variation both intra and inter days. The accuracy of the method ranged from 82.86% to 119.83%. (2-Methoxymethylethoxy)propanol, 2-phenoxyethanol, and 1-phenoxy-2-propanol were mainly detected in wet wipes.

Mathematical modeling of wiped-film evaporators

International Nuclear Information System (INIS)

Sommerfeld, J.T.

1976-05-01

A mathematical model and associated computer program were developed to simulate the steady-state operation of wiped-film evaporators for the concentration of typical waste solutions produced at the Savannah River Plant. In this model, which treats either a horizontal or a vertical wiped-film evaporator as a plug-flow device with no backmixing, three fundamental phenomena are described: sensible heating of the waste solution, vaporization of water, and crystallization of solids from solution. Physical property data were coded into the computer program, which performs the calculations of this model. Physical properties of typical waste solutions and of the heating steam, generally as analytical functions of temperature, were obtained from published data or derived by regression analysis of tabulated or graphical data. Preliminary results from tests of the Savannah River Laboratory semiworks wiped-film evaporators were used to select a correlation for the inside film heat transfer coefficient. This model should be a useful aid in the specification, operation, and control of the full-scale wiped-film evaporators proposed for application under plant conditions. In particular, it should be of value in the development and analysis of feed-forward control schemes for the plant units. Also, this model can be readily adapted, with only minor changes, to simulate the operation of wiped-film evaporators for other conceivable applications, such as the concentration of acid wastes

EPA Method 3135.2I: Cyanide, Total and Amenable in Aqueous and Solid Samples Automated Colorimetric With Manual Digestion

Science.gov (United States)

This method describes procedures for preparation and analysis of solid, water and wipe samples for detection and measurement of cyanide amendable to chlorination using acid digestion and spectrophotometry.

Representation of hysteresis with wipe-out memory

International Nuclear Information System (INIS)

Friedman, G.; Cha, K.

2001-01-01

A model representing scalar hysteretic systems with wipe-out memory is proposed. In this model a hysteresis operator is represented as a power series expansion containing an infinite number of terms in general. It is shown that this representation converges to any given hysteresis relation having wipe-out memory as long as the output of the given hysteresis varies sufficiently smoothly with input history. [copyright] 2001 American Institute of Physics

Comprehensive Study of Human External Exposure to Organophosphate Flame Retardants via Air, Dust, and Hand Wipes: The Importance of Sampling and Assessment Strategy.

Science.gov (United States)

Xu, Fuchao; Giovanoulis, Georgios; van Waes, Sofie; Padilla-Sanchez, Juan Antonio; Papadopoulou, Eleni; Magnér, Jorgen; Haug, Line Småstuen; Neels, Hugo; Covaci, Adrian

2016-07-19

We compared the human exposure to organophosphate flame retardants (PFRs) via inhalation, dust ingestion, and dermal absorption using different sampling and assessment strategies. Air (indoor stationary air and personal ambient air), dust (floor dust and surface dust), and hand wipes were sampled from 61 participants and their houses. We found that stationary air contains higher levels of ΣPFRs (median = 163 ng/m(3), IQR = 161 ng/m(3)) than personal air (median = 44 ng/m(3), IQR = 55 ng/m(3)), suggesting that the stationary air sample could generate a larger bias for inhalation exposure assessment. Tris(chloropropyl) phosphate isomers (ΣTCPP) accounted for over 80% of ΣPFRs in both stationary and personal air. PFRs were frequently detected in both surface dust (ΣPFRs median = 33 100 ng/g, IQR = 62 300 ng/g) and floor dust (ΣPFRs median = 20 500 ng/g, IQR = 30 300 ng/g). Tris(2-butoxylethyl) phosphate (TBOEP) accounted for 40% and 60% of ΣPFRs in surface and floor dust, respectively, followed by ΣTCPP (30% and 20%, respectively). TBOEP (median = 46 ng, IQR = 69 ng) and ΣTCPP (median = 37 ng, IQR = 49 ng) were also frequently detected in hand wipe samples. For the first time, a comprehensive assessment of human exposure to PFRs via inhalation, dust ingestion, and dermal absorption was conducted with individual personal data rather than reference factors of the general population. Inhalation seems to be the major exposure pathway for ΣTCPP and tris(2-chloroethyl) phosphate (TCEP), while participants had higher exposure to TBOEP and triphenyl phosphate (TPHP) via dust ingestion. Estimated exposure to ΣPFRs was the highest with stationary air inhalation (median =34 ng·kg bw(-1)·day(-1), IQR = 38 ng·kg bw(-1)·day(-1)), followed by surface dust ingestion (median = 13 ng·kg bw(-1)·day(-1), IQR = 28 ng·kg bw(-1)·day(-1)), floor dust ingestion and personal air inhalation. The median dermal exposure on hand wipes was 0.32 ng·kg bw(-1)·day(-1) (IQR

Role of surface energy and nano-roughness in the removal efficiency of bacterial contamination by nonwoven wipes from frequently touched surfaces

Science.gov (United States)

Edwards, Nicholas W. M.; Best, Emma L.; Connell, Simon D.; Goswami, Parikshit; Carr, Chris M.; Wilcox, Mark H.; Russell, Stephen J.

2017-12-01

Healthcare associated infections (HCAIs) are responsible for substantial patient morbidity, mortality and economic cost. Infection control strategies for reducing rates of transmission include the use of nonwoven wipes to remove pathogenic bacteria from frequently touched surfaces. Wiping is a dynamic process that involves physicochemical mechanisms to detach and transfer bacteria to fibre surfaces within the wipe. The purpose of this study was to determine the extent to which systematic changes in fibre surface energy and nano-roughness influence removal of bacteria from an abiotic polymer surface in dry wiping conditions, without liquid detergents or disinfectants. Nonwoven wipe substrates composed of two commonly used fibre types, lyocell (cellulosic) and polypropylene, with different surface energies and nano-roughnesses, were manufactured using pilot-scale nonwoven facilities to produce samples of comparable structure and dimensional properties. The surface energy and nano-roughness of some lyocell substrates were further adjusted by either oxygen (O2) or hexafluoroethane (C2F6) gas plasma treatment. Static adpression wiping of an inoculated surface under dry conditions produced removal efficiencies of between 9.4% and 15.7%, with no significant difference (p < 0.05) in the relative removal efficiencies of Escherichia coli, Staphylococcus aureus or Enterococcus faecalis. However, dynamic wiping markedly increased peak wiping efficiencies to over 50%, with a minimum increase in removal efficiency of 12.5% and a maximum increase in removal efficiency of 37.9% (all significant at p < 0.05) compared with static wiping, depending on fibre type and bacterium. In dry, dynamic wiping conditions, nonwoven wipe substrates with a surface energy closest to that of the contaminated surface produced the highest E. coli removal efficiency, while the associated increase in fibre nano-roughness abrogated this trend with S. aureus and E. faecalis.

The development of a new three-step protocol to determine the efficacy of disinfectant wipes on surfaces contaminated with Staphylococcus aureus.

Science.gov (United States)

Williams, G J; Denyer, S P; Hosein, I K; Hill, D W; Maillard, J-Y

2007-12-01

We developed a three-step protocol to quantify the efficacy of disinfectant wipes, their ability to remove and prevent microbial transfer from surfaces and their overall antimicrobial activity. Meticillin-resistant (MRSA) or -susceptible (MSSA) Staphylococcus aureus (6-7 log(10)cfu) were inoculated onto stainless steel discs with or without organic load and dried. Grapefruit extract-containing test wipes and unmedicated control wipes were used. In step 1, wipes were mechanically rotated against surfaces for 10s at 60rpm, exerting a weight of 100+/-5g. Bacterial removal was assessed by transferring the steel discs to neutraliser, resuspending and counting remaining bacteria. In step 2, bacterial transfer from wipes was assessed by eight consecutive mechanical adpression transfers to agar/neutraliser plates. Step 3 was the measurement of antimicrobial activity by direct inoculation of the wipes for 10s followed by neutralisation and enumeration. Test wipes achieved a significantly higher bacterial cell removal than control wipes on all surfaces (P<0.05). The low bactericidal activity of the wipes (<1 log(10) reduction when directly inoculated) and the subsequent survival of bacteria on the wipes, however, led to repeated microbial transfer when initially high contamination levels were present. There were no differences between MRSA and MSSA in removal, transfer or antimicrobial activity. The three-step method is a useful tool for developing future guidelines to assess the ability of wipes to disinfect surfaces.

A rapid alpha dosimeter for measuring nasal cavity wipe matter

International Nuclear Information System (INIS)

Tuo, Xianguo; Mu, Keliang; Zhong, Hongmei; Yang, Guoshan; Yuan, Yong

2008-01-01

Full text: It is necessary for people who work in the special condition to know whether the alpha radiation is inhaled through detecting quickly nasal cavity wipe matter. This measure method requires that the dosimeter must be portable and easy to operate, and be able to overcome some disadvantages, such as high environment background, few sample quantity, short measure time, and so on. Based on the above requests, a new intelligent portable system is developed for measuring alpha radiated degree, which is suitable for solid wiping matter detected of which diameter is smaller than 20 mm. This system is mainly made up of the detector, self- circumrotating sample shelf, I/A converter, signal gathering and processing system, power supply etc. The system chooses PIPS (Planar Implanted Passivated Silicon) detector which is a designed logical signal gathering hardware. The detector is with small volume, high efficiency and good resolution. PIPS detector doesn't need working gas and is easy to use compared with gas ionization chamber detector. The self-circumrotating sample shelf carries on measuring samples cubically and this improves the accuracy. The system uses compensating adjustment technology to remove background, automatically identify and compensate for radon, thoron and progeny interference, and is able to obtain the reliable measurement result. And the power for this system is supplied simultaneously by 220 V AV power and rechargeable Li-battery supply; it also has a mobile storage for more environments. The dosimeter is used to measure the samples of which diameters are 10∼20 mm , the result of tests shows that: detection efficiency ≥ 30%, background count ≤ 0.2 cpm, stability ≤ 0.3% / h, working temperature -10∼40 C degrees. The parameters of the system basically meet the rapid measurement in a special environment, so it has valuable application prospect in the field of environment, laboratories, and nuclear facilities etc. (author)

Impact of antimicrobial wipes compared with hypochlorite solution on environmental surface contamination in a health care setting: A double-crossover study.

Science.gov (United States)

Siani, Harsha; Wesgate, Rebecca; Maillard, Jean-Yves

2018-05-11

Antimicrobial wipes are increasingly used in health care settings. This study evaluates, in a clinical setting, the efficacy of sporicidal wipes versus a cloth soaked in a 1,000 ppm chlorine solution. A double-crossover study was performed on 2 different surgical and cardiovascular wards in a 1,000-bed teaching hospital over 29 weeks. The intervention period that consisted of surface decontamination with the preimpregnated wipe or cloth soaked in chlorine followed a 5-week baseline assessment of microbial bioburden on surfaces. Environmental samples from 11 surfaces were analyzed weekly for their microbial content. A total of 1,566 environmental samples and 1,591 ATP swabs were analyzed during the trial. Overall, there were significant differences in the recovery of total aerobic bacteria (P < .001), total anaerobic bacteria (P < .001), and ATP measurement (P < .001) between wards and between the different parts of the crossover study. Generally, the use of wipes produced the largest reduction in the total aerobic and anaerobic counts when compared with the baseline data or the use of 1,000 ppm chlorine. Collectively, the introduction of training plus daily wipe disinfection significantly reduced multidrug-resistant organisms recovered from surfaces. Reversion to using 1,000 ppm chlorine resulted in the number of sites positive for multidrug-resistant organisms rising again. This double-crossover study is the first controlled field trial comparison of using preimpregnated wipes versus cotton cloth dipped into a bucket of hypochlorite to decrease surface microbial bioburden. The results demonstrate the superiority of the preimpregnated wipes in significantly decreasing microbial bioburden from high-touch surfaces. Copyright © 2018 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved.

Wipe sampling of amphetamine-type stimulants and recreational drugs on selected household surfaces with analysis by ultra-performance liquid chromatography quadrupole time-of-flight mass spectrometry

International Nuclear Information System (INIS)

Madireddy, Sri Bharat; Bodeddula, Vanaja Reddy; Mansani, Sravan Kumar; Wells, Martha J.M.; Boles, Jeffrey O.

2013-01-01

Highlights: • Degree of sorption of eight drugs on eleven countertop surfaces was investigated. • Surface composition, volatility and solvent composition played a role in sorption. • Solvent-dependent migration was a key factor of consideration during remediation. • SPME-assisted volatility studies provided evidence for varying degrees of recovery. • Rapid three minute UPLC-QTOF method was developed to quantify the eight compounds. -- Abstract: Sorption characteristics of eight drugs related to recreational and clandestine activity—amphetamine, cocaine, heroin, N-formyl amphetamine, N-formyl methamphetamine, methamphetamine, 3, 4-methylenedioxymethamphetamine (MDMA), and pseudoephedrine—were evaluated on selected kitchen countertop surfaces. Methanol-dampened Whatman™ 40 filter paper wipes were used to collect samples from eleven surfaces including alkyd resin, ceramic tiles, glass, granite, laminate, limestone, marble, quartz compac, quartz real, soap stone, and stainless steel. The filter paper wipes were analyzed by a rapid three-minute UPLC-QTOF method, following ammonium acetate buffer (pH 5.8–6.2) extraction. The average percentage recoveries after 15 h of exposure to the surface materials tested, was found to be highest for cocaine and MDMA and lowest for amphetamine and methamphetamine. Among the eleven countertop surfaces, overall recoveries for marble were observed to be the least, whereas soapstone, quartz compac and stainless steel were among the highest. Scanning electron microscopic images of the surfaces provided a unique view of surface irregularities that potentially influenced drug recovery. Aging, migration, solvent composition, and volatility were examined. The variation in recovery of drugs was attributed to four key factors: compound volatility, surface composition, surface—compound interaction, and solvent composition

Wipe sampling of amphetamine-type stimulants and recreational drugs on selected household surfaces with analysis by ultra-performance liquid chromatography quadrupole time-of-flight mass spectrometry

Energy Technology Data Exchange (ETDEWEB)

Madireddy, Sri Bharat; Bodeddula, Vanaja Reddy; Mansani, Sravan Kumar; Wells, Martha J.M.; Boles, Jeffrey O., E-mail: jboles@tntech.edu

2013-06-15

Highlights: • Degree of sorption of eight drugs on eleven countertop surfaces was investigated. • Surface composition, volatility and solvent composition played a role in sorption. • Solvent-dependent migration was a key factor of consideration during remediation. • SPME-assisted volatility studies provided evidence for varying degrees of recovery. • Rapid three minute UPLC-QTOF method was developed to quantify the eight compounds. -- Abstract: Sorption characteristics of eight drugs related to recreational and clandestine activity—amphetamine, cocaine, heroin, N-formyl amphetamine, N-formyl methamphetamine, methamphetamine, 3, 4-methylenedioxymethamphetamine (MDMA), and pseudoephedrine—were evaluated on selected kitchen countertop surfaces. Methanol-dampened Whatman™ 40 filter paper wipes were used to collect samples from eleven surfaces including alkyd resin, ceramic tiles, glass, granite, laminate, limestone, marble, quartz compac, quartz real, soap stone, and stainless steel. The filter paper wipes were analyzed by a rapid three-minute UPLC-QTOF method, following ammonium acetate buffer (pH 5.8–6.2) extraction. The average percentage recoveries after 15 h of exposure to the surface materials tested, was found to be highest for cocaine and MDMA and lowest for amphetamine and methamphetamine. Among the eleven countertop surfaces, overall recoveries for marble were observed to be the least, whereas soapstone, quartz compac and stainless steel were among the highest. Scanning electron microscopic images of the surfaces provided a unique view of surface irregularities that potentially influenced drug recovery. Aging, migration, solvent composition, and volatility were examined. The variation in recovery of drugs was attributed to four key factors: compound volatility, surface composition, surface—compound interaction, and solvent composition.

A pilot study to assess the effectiveness and cost of routine universal use of peracetic acid sporicidal wipes in a real clinical environment.

Science.gov (United States)

Saha, Avinandan; Botha, Stefan Louis; Weaving, Paul; Satta, Giovanni

2016-11-01

Peracetic acid sporicidal wipes have been shown to be an effective disinfectant, but in controlled test environments. Their high cost may restrict use. This pilot study investigated the efficacy and compared the costs of routine universal use of peracetic acid sporicidal wipes versus sporicidal quaternary ammonium compound and alcohol wipes in the disinfection of a hospital environment. The routine universal use of peracetic acid wipes (Clinell Sporicidal; GAMA Healthcare Ltd, London, UK) was allocated to a study ward, whereas the control ward continued with the use of quaternary ammonium compound wipes (Tuffie 5; Vernacare, Bolton, UK) and alcohol wipes (PDI Sani-Cloth 70; PDI, Flint, UK). Twenty high-touch areas in the 2 wards were sampled for the presence of indicator organisms. The weekly detection rates of indicator organisms and weekly healthcare associated infection (HCAI) rates in the 2 wards were compared and examined for decreasing trends over the trial period. The detection rates of indicator organisms and HCAI rates were not significantly different in the 2 wards, and did not decrease significantly over the trial period. However, the peracetic acid wipes seem to be more effective against gram-negative organisms but at a significantly higher cost. Further prospective studies are needed to assess the cost-effectiveness of peracetic acid wipes. Copyright © 2016 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved.

Microbiological Sampling Methods and Sanitation of Edible Plants Grown on ISS

Science.gov (United States)

Parrish, Charles H. II; Khodadad, Christina L.; Garland, Nathaniel T.; Larson, Brian D.; Hummreick, Mary E.

2013-01-01

Pathogenic microbes on the surfaces of salad crops and growth chambers pose a threat to the health of crew on International Space Station. For astronauts to safely consume spacegrown vegetables produced in NASA's new vegetable production unit, VEGGIE, three technical challenges must be overcome: real-time sampling, microbiological analysis, and sanitation. Raphanus sativus cultivar Cherry Bomb II and Latuca sativa cultivar Outredgeous, two saled crops to be grown in VEGGIE, were inoculated with Salmonella enterica serovar Typhimurium (S. Typhimurium), a bacterium known to cause food-borne illness Tape- and swab-based sampling techniques were optimized for use in microgravity and assessed for effectiveness in recovery of bacteria from crop surfaces: Rapid pathogen detection and molecular analyses were performed via quantitative real-time polymerase chain reactiop using LightCycler® 480 and RAZOR® EX, a scaled-down instrument that is undergoing evaluation and testing for future flight hardware. These methods were compared with conventional, culture-based methods for the recovery of S. Typhimurium colonies. A sterile wipe saturated with a citric acid-based, food-grade sanitizer was applied to two different surface materials used in VEGGIE flight hardware that had been contaminated with the bacterium Pseudomonas aeruginosa,. another known human pathogen. To sanitize surfaces, wipes were saturated with either the sanitizer or sterile deionized water and applied to each surface. Colony forming units of P. aeruginosa grown on tryptic soy agar plates were enumerated from surface samples after sanitization treatments. Depending on the VEGGIE hardware material, 2- to 4.5-log10 reductions in colony-forming units were observed after sanitization. The difference in recovery of S. Typhimurium between tape- and swab- based sampling techniques was insignificant. RAZOR® EX rapidly detected S. Typhimurium present in both raw culture and extracted DNA samples.

Surface dust wipes are the best predictors of blood leads in young children with elevated blood lead levels

Energy Technology Data Exchange (ETDEWEB)

Gulson, Brian, E-mail: brian.gulson@mq.edu.au [Graduate School of the Environment, Macquarie University, North Ryde NSW 2109 (Australia); CSIRO Earth Science and Resource Engineering, North Ryde NSW 2113 (Australia); Anderson, Phil [Information and Statistics Group, Australian Institute of Health and Welfare, Canberra ACT 2601 (Australia); Faculty of Health, University of Canberra, Canberra ACT 2601 (Australia); Taylor, Alan [Department of Psychology, Macquarie University, Sydney NSW 2109 (Australia)

2013-10-15

Background: As part of the only national survey of lead in Australian children, which was undertaken in 1996, lead isotopic and lead concentration measurements were obtained from children from 24 dwellings whose blood lead levels were ≥15 µg/dL in an attempt to determine the source(s) of their elevated blood lead. Comparisons were made with data for six children with lower blood lead levels (<10 µg/dL). Methods: Thermal ionisation and isotope dilution mass spectrometry were used to determine high precision lead isotopic ratios ({sup 208}Pb/{sup 206}Pb, {sup 207}Pb/{sup 206}Pb and {sup 206}Pb/{sup 204}Pb) and lead concentrations in blood, dust from floor wipes, soil, drinking water and paint (where available). Evaluation of associations between blood and the environmental samples was based on the analysis of individual cases, and Pearson correlations and multiple regression analyses based on the whole dataset. Results and discussion: The correlations showed an association for isotopic ratios in blood and wipes (r=0.52, 95% CI 0.19–0.74), blood and soil (r=0.33, 95% CI −0.05–0.62), and blood and paint (r=0.56, 95% CI 0.09–0.83). The regression analyses indicated that the only statistically significant relationship for blood isotopic ratios was with dust wipes (B=0.65, 95% CI 0.35–0.95); there were no significant associations for lead concentrations in blood and environmental samples. There is a strong isotopic correlation of soils and house dust (r=0.53, 95% CI 0.20–0.75) indicative of a common source(s) for lead in soil and house dust. In contrast, as with the regression analyses, no such association is present for bulk lead concentrations (r=−0.003, 95% CI −0.37–0.36), the most common approach employed in source investigations. In evaluation of the isotopic results on a case by case basis, the strongest associations were for dust wipes and blood. -- Highlights: • Children with elevated blood lead ≥15 µg/dL compared with a group with <10

Development, validation and testing of a skin sampling method for assessment of metal exposure.

Science.gov (United States)

Erfani, Behnaz; Midander, Klara; Lidén, Carola; Julander, Anneli

2017-07-01

Nickel, cobalt and chromium are frequent skin sensitizers. Skin exposure results in eczema in sensitized individuals, the risk being related to the skin dose. To develop a self-sampling method for quantification of skin exposure to metals, to validate the method, and to assess its feasibility. Defined metal doses (0.01-5 µg) were applied to the fingers of 5 participants. Skin areas (2 cm 2 ) were sampled with 1% HNO 3 , either as 0.1 ml on a swab, or as 0.5 ml on a wipe. Furthermore, 17 participants performed self-sampling by swab after 2 h of leisure activity. Samples were extracted in 1% HNO 3 and analysed by inductively coupled plasma mass spectrometry. The sampling efficiency by swab was 46%, as compared with 93% for acid wipe sampling, for all tested doses. Most metal from the skin dose was detected in the first swab (33-43%). Despite lower sampling efficiency by swab, skin doses of metals following 2 h of leisure activity without hand washing were quantified in all participants, and ranged from 0.0016 to 0.15 µg/cm 2 , from 0.00014 to -0.0020 µg/cm 2 and from 0.00048 to -0.027 µg/cm 2 for nickel, cobalt, and chromium, respectively. The results indicate a future potential of skin sampling by swab to detect and monitor metals on skin by self-sampling. This will contribute to better knowledge of metal skin exposure among dermatitis patients, workers, and the general population. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Pressurized liquid extraction-gas chromatography-mass spectrometry analysis of fragrance allergens, musks, phthalates and preservatives in baby wipes.

Science.gov (United States)

Celeiro, Maria; Lamas, J Pablo; Garcia-Jares, Carmen; Llompart, Maria

2015-03-06

Baby wipes and wet toilet paper are specific hygiene care daily products used on newborn and children skin. These products may contain complexes mixtures of harmful chemicals. A method based on pressurized liquid extraction (PLE) followed by gas chromatography-mass spectrometry (GC-MS) has been developed for the simultaneous determination of sixty-five chemical compounds (fragrance allergens, preservatives, musks, and phthalates) in wipes and wet toilet paper for children. These compounds are legislated in Europe according Regulation EC No 1223/2009, being twelve of them banned for their use in cosmetics, and one of them, 3-iodo-2-propynyl butylcarbamate (IPBC), is banned in products intended for children under 3 years. Also, propyl-, and butylparaben will be prohibited in leave-on cosmetic products designed for application on the nappy area of children under 3 years from April 2015. PLE is a fast, simple, easily automated technique, which permits to integrate a clean-up step during the extraction process reducing analysis time and stages. The proposed PLE-based procedure was optimized on real non-spiked baby wipe samples by means of experimental design to study the influence on extraction of parameters such as extraction solvent, temperature, extraction time, and sorbent type. Under the selected conditions, the method was validated showing satisfactory linearity, and intra-day, and inter-day precision. Recoveries were between 80-115% for most of the compounds with relative standard deviations (RSD) lower than 15%. Finally, twenty real samples were analyzed. Thirty-six of the target analytes were detected, highlighting the presence of phenoxyethanol in all analyzed samples at high concentration levels (up to 0.8%, 800μgg(-1)). Methyl paraben (MeP), and ethyl paraben (EtP) were found in 40-50% of the samples, and the recently banned isobutyl paraben (iBuP) and isopropyl paraben (iPrP), were detected in one and seven samples, respectively, at concentrations between

Wet Wipe Allergens: Retrospective Analysis From the North American Contact Dermatitis Group 2011-2014.

Science.gov (United States)

Warshaw, Erin M; Aschenbeck, Kelly A; Zug, Kathryn A; Belsito, Donald V; Zirwas, Matthew J; Fowler, Joseph F; Taylor, James S; Sasseville, Denis; Fransway, Anthony F; DeLeo, Vincent A; Marks, James G; Pratt, Melanie D; Maibach, Howard I; Mathias, C G Toby; DeKoven, Joel G

Although there are several case reports of wet wipe-associated contact dermatitis, the prevalence of wipes as a source of allergic contact dermatitis in larger populations and the responsible allergens are largely unknown. The aim of the study was to determine the prevalence of wet wipes as a source of contact allergy and the most commonly associated allergens in a North American tertiary referral patch test population. Data collected from 2011 to 2014 by the North American Contact Dermatitis Group was used to conduct a retrospective cross-sectional analysis of patient demographics and patch test results associated with the triple-digit source code for "wet wipe." Of the 9037 patients patch tested during the study period, 79 (0.9%) had a positive patch test reaction to an allergen identified with a wet wipe source. The most commonly associated allergens were preservatives, including the following: methylisothiazolinone (MI) (59.0%), methylchloroisothiazolinone (MCI)/MI (35.6%), bronopol (2-bromo-2-nitropropane-1,3-diol) (27.4%), and iodopropynyl butylcarbamate (12.3%). Fragrance (combined) represented 12.3%. Anal/genital dermatitis was 15 times more likely (P contact allergy had their contact allergens detected by the North American Contact Dermatitis Group screening series. Wet wipes are an important source of contact allergy. Preservatives are the main allergens, especially isothiazolinones.

Disinfectant wipes are appropriate to control microbial bioburden from surfaces: use of a new ASTM standard test protocol to demonstrate efficacy.

Science.gov (United States)

Sattar, S A; Bradley, C; Kibbee, R; Wesgate, R; Wilkinson, M A C; Sharpe, T; Maillard, J-Y

2015-12-01

The use of disinfectant pre-soaked wipes (DPW) to decontaminate high-touch environmental surfaces (HTES) by wiping is becoming increasingly widespread in the healthcare environment. However, DPW are rarely tested using conditions simulating their field use, and the label claims of environmental surface disinfectants seldom include wiping action. To evaluate the new E2967-15 standard test specific to wipes, particularly their ability to decontaminate surfaces and to transfer acquired contamination to clean surfaces. ASTM Standard E2967-15 was used by three independent laboratories to test the efficacy of five types of commercially available wipe products. All data generated were pulled together, and reproducibility and repeatability of the standard were measured. All the commercial DPW tested achieved a >4log10 (>99.99%) reduction in colony-forming units (CFU) of Staphylococcus aureus and Acinetobacter baumanii with 10s of wiping, but only one DPW containing 0.5% accelerated H2O2 prevented the transfer of bacteria to another surface. This newly introduced standard method represents a significant advance in assessing DPW for microbial decontamination of HTES, and should greatly assist research and development, and in making more relevant and reliable claims on marketed DPW. Copyright © 2015. Published by Elsevier Ltd.

Wipe selection for the analysis of surface materials containing chemical warfare agent nitrogen mustard degradation products by ultra-high pressure liquid chromatography-tandem mass spectrometry.

Science.gov (United States)

Willison, Stuart A

2012-12-28

Degradation products arising from nitrogen mustard chemical warfare agent were deposited on common urban surfaces and determined via surface wiping, wipe extraction, and liquid chromatography–tandem mass spectrometry detection. Wipes investigated included cotton gauze, glass fiber filter, non-woven polyester fiber and filter paper, and surfaces included several porous (vinyl tile, painted drywall, wood) and mostly non-porous (laminate, galvanized steel, glass) surfaces. Wipe extracts were analyzed by ultra-high pressure liquid chromatography–tandem mass spectrometry (UPLC–MS/MS) and compared with high performance liquid chromatography–tandem mass spectrometry (HPLC–MS/MS) results. An evaluation of both techniques suggests UPLC–MS/MS provides a quick and sensitive analysis of targeted degradation products in addition to being nearly four times faster than a single HPLC run, allowing for greater throughput during a wide-spread release concerning large-scale contamination and subsequent remediation events. Based on the overall performance of all tested wipes, filter paper wipes were selected over other wipes because they did not contain interferences or native species (TEA and DEA) associated with the target analytes, resulting in high percent recoveries and low background levels during sample analysis. Other wipes, including cotton gauze, would require a pre-cleaning step due to the presence of large quantities of native species or interferences of the targeted analytes. Percent recoveries obtained from a laminate surface were 47–99% for all nitrogen mustard degradation products. The resulting detection limits achieved from wipes were 0.2 ng/cm(2) for triethanolamine (TEA), 0.03 ng/cm(2) for N-ethyldiethanolamine (EDEA), 0.1 ng/cm(2) for N-methyldiethanolamine (MDEA), and 0.1 ng/cm(2) for diethanolamine (DEA).

Effect on skin hydration of using baby wipes to clean the napkin area of newborn babies: assessor-blinded randomised controlled equivalence trial

Directory of Open Access Journals (Sweden)

Lavender Tina

2012-06-01

Full Text Available Abstract Background Some national guidelines recommend the use of water alone for napkin cleansing. Yet, there is a readiness, amongst many parents, to use baby wipes. Evidence from randomised controlled trials, of the effect of baby wipes on newborn skin integrity is lacking. We conducted a study to examine the hypothesis that the use of a specifically formulated cleansing wipe on the napkin area of newborn infants ( Methods A prospective, assessor-blinded, randomised controlled equivalence trial was conducted during 2010. Healthy, term babies (n = 280, recruited within 48 hours of birth, were randomly assigned to have their napkin area cleansed with an alcohol-free baby wipe (140 babies or cotton wool and water (140 babies. Primary outcome was change in hydration from within 48 hours of birth to 4 weeks post-birth. Secondary outcomes comprised changes in trans-epidermal water loss, skin surface pH and erythema, presence of microbial skin contaminants/irritants at 4 weeks and napkin dermatitis reported by midwife at 4 weeks and mother during the 4 weeks. Results Complete hydration data were obtained for 254 (90.7 % babies. Wipes were shown to be equivalent to water and cotton wool in terms of skin hydration (intention-to-treat analysis: wipes 65.4 (SD 12.4 vs. water 63.5 (14.2, p = 0.47, 95 % CI -2.5 to 4.2; per protocol analysis: wipes 64.6 (12.4 vs. water 63.6 (14.3, p = 0.53, 95 % CI -2.4 to 4.2. No significant differences were found in the secondary outcomes, except for maternal-reported napkin dermatitis, which was higher in the water group (p = 0.025 for complete responses. Conclusions Baby wipes had an equivalent effect on skin hydration when compared with cotton wool and water. We found no evidence of any adverse effects of using these wipes. These findings offer reassurance to parents who choose to use baby wipes and to health professionals who support their use. Trial registration Current Controlled

Effectiveness of disinfectant wipes for decontamination of bacteria on patients' environmental and medical equipment surfaces at Siriraj Hospital.

Science.gov (United States)

Seenama, Chakkraphong; Tachasirinugune, Peenithi; Jintanothaitavorn, Duangporn; Kachintorn, Kanchana; Thamlikitkul, Visanu

2013-02-01

To determine the effectiveness of Virusolve+ disinfectant wipes and PAL disinfectant wipes for decontamination of inoculated bacteria on patients' environmental and medical equipment surfaces at Siriraj Hospital. Tryptic soy broths containing MRSA and XDR A. baumannii were painted onto the surfaces of patient's stainless steel bed rail, patient's fiber footboard, control panel of infusion pump machine and control panel of respirator. The contaminated surfaces were cleaned by either tap water, tap water containing detergent, Virusolve+ disinfectant wipes or PAL disinfectant wipes. The surfaces without any cleaning procedures served as the control surface. The contaminated surfaces cleaned with the aforementioned procedures and control surfaces were swabbed with cotton swabs. The swabs were streaked on agar plates to determine the presence of MRSA and XDR A. baumannii. MRSA and XDR A. baumannii were recovered from all control surfaces. All surfaces cleaned with tap water or tap water containing detergent revealed presence of both MRSA and XDR A. baumannii. However the amounts of bacteria on the surfaces cleaned with tap water containing detergent were less than those cleaned with tap water alone. All surfaces cleaned with PAL disinfectant wipes also revealed presence of both MRSA and XDR A. baumannii. However the amounts of bacteria on the surfaces cleaned with PAL disinfectant wipes were less than those cleaned with tap water containing detergent. No bacteria were recovered from all surfaces cleaned with Virusolve+ disinfectant wipes. Virusolve+ disinfectant wipes were more effective than tap water; tap water containing detergent and PAL disinfectant wipes for decontamination of bacteria inoculated on patients environmental and medical equipment surfaces at Siriraj Hospital.

Contamination monitoring of Na 131 I levels in therapy unit of Research Institute for Nuclear Medicine, Tehran University of Medical Sciences by indirect method (Wipe test)

International Nuclear Information System (INIS)

Beiki, D.; Shahhosseini, S.; Eftekhari, M.; Takavar, A.; Fard-Esfahani, A.

2003-01-01

Contamination with radiopharmaceuticals in nuclear medicine centres in addition to being a health concern requires time consuming decontamination efforts. According to Nuclear Regulatory Commission Contamination should be monitored in nuclear medicine centers where radiopharmaceuticals are prepared and administrated at the end of each working session; otherwise, contamination spread to other areas not only equipment but also personnel and other people will be expected. The wipe test for the presence of radioactivity is accomplished by wiping the surface over an area approximately 100 cm 2 with an absorbent paper, then counting it in an appropriate radiation detector. In this study, contamination monitoring of patient's rooms (4 rooms), entrance corridor, patient's corridor, waiting room, control room (nursing station), radiopharmaceutical storage room in therapy unit of Research Institute for Nuclear Medicine, Shariati hospital was performed by indirect method. Based on the results, some areas including storage room were contaminated. There was also a direct relationship between dose administrated and levels of contamination in patient's rooms. Regarding high uptake of iodine by thyroid gland and damaging effects of Na 131 I, weekly wipe tests are required to determine the level of contamination. Patient's rooms after discharging the patients and before re hospitalization specially should be checked. If these tests reveal contamination over standard levels, appropriate decontamination procedures should be carried out immediately

Remote Wiping and Secure Deletion on Mobile Devices: A Review.

Science.gov (United States)

Leom, Ming Di; Choo, Kim-Kwang Raymond; Hunt, Ray

2016-11-01

Mobile devices have become ubiquitous in almost every sector of both private and commercial endeavors. As a result of such widespread use in everyday life, many users knowingly and unknowingly save significant amounts of personal and/or commercial data on these mobile devices. Thus, loss of mobile devices through accident or theft can expose users-and their businesses-to significant personal and corporate cost. To mitigate this data leakage issue, remote wiping features have been introduced to modern mobile devices. Given the destructive nature of such a feature, however, it may be subject to criminal exploitation (e.g., a criminal exploiting one or more vulnerabilities to issue a remote wiping command to the victim's device). To obtain a better understanding of remote wiping, we survey the literature, focusing on existing approaches to secure flash storage deletion and provide a critical analysis and comparison of a variety of published research in this area. In support of our analysis, we further provide prototype experimental results for three Android devices, thus providing both a theoretical and applied focus to this article as well as providing directions for further research. © 2016 American Academy of Forensic Sciences.

Broad Spectrum Sanitizing Wipes with Food Additives, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — Microcide proposes to develop novel multipurpose non-toxic sanitizing wipes that are aqueous based, have shelf life of 3-5 years, have broad spectrum microbicidal...

Effectiveness of cleaning-disinfection wipes and sprays against multidrug-resistant outbreak strains.

Science.gov (United States)

Kenters, Nikki; Huijskens, Elisabeth G W; de Wit, Sophie C J; van Rosmalen, Joost; Voss, Andreas

2017-08-01

Hospital rooms play an important role in the transmission of several health care-associated pathogens. During the last few years, a number of innovative cleaning-disinfecting products have been brought to market. In this study, commercially available products combining cleaning and disinfection were compared, using 2 different application methods. The aim was to determine which product was most effective in simultaneous cleaning and disinfection of surfaces. Seven cleaning-disinfecting wipes and sprays based on different active ingredients were tested for their efficacy in removal of microbial burden and proteins. Efficacy was tested with known Dutch outbreak strains: vancomycin-resistant enterococci (VRE), Klebsiella pneumoniae OXA-48, or Acinetobacter baumannii. For all bacteria, ready-to-use cleaning-disinfecting products reduced the microbial count with a log 10 reduction >5 with a 5-minute exposure time, with the exception of a spray based on hydrogen peroxide. Omitting the aforementioned hydrogen peroxide spray, there were no significant differences between use of a wipe or spray in bacterial load reduction. Using adenosine triphosphate (ATP) measurements, a significant difference in log 10 relative light units (RLU) reduction between various bacteria (P ≤ .001) was observed. In general, a >5 log 10 reduction of colony forming units (CFU) for tested wipes and sprays was obtained for all tested bacteria strains, with exception of hydrogen peroxide spray and VRE. Although ATP may show a difference between pre- and postcleaning, RLU reduction does not correlate with actual CFU reductions. Copyright © 2017 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved.

Patient and environmental service employee satisfaction of using germicidal bleach wipes for patient room cleaning.

Science.gov (United States)

Aronhalt, Kimberly C; McManus, James; Orenstein, Robert; Faller, Rebecca; Link, Mary

2013-01-01

More healthcare institutions are using bleach products which are sporicidal to reduce Clostridium difficile infection (CDI). There may be patient and employee concerns about the appearance of bleach residue left on surfaces, odors, and respiratory tract irritation. The intervention used bleach wipes for daily and terminal patient room cleaning to reduce transmission of CDI and was implemented on patient care units with a relatively high incidence of CDI. Both patients and Environmental Services (ES) staff were surveyed to assess their satisfaction of the bleach wipe product used during room cleaning. Patients (n = 94) (91%) continued to be very satisfied with how well their rooms were cleaned every day. Bleach wipes were well tolerated by patients (n = 44) (100%) surveyed on the medical units and less tolerated by patients (n = 50) (22%) on the hematology-oncology units. ES staff (6) reported less satisfaction and more respiratory irritation from using the bleach wipes; however, later their satisfaction improved. © 2012 National Association for Healthcare Quality.

Detection of Nonvolatile Inorganic Oxidizer-Based Explosives from Wipe Collections by Infrared Thermal Desorption-Direct Analysis in Real Time Mass Spectrometry.

Science.gov (United States)

Forbes, Thomas P; Sisco, Edward; Staymates, Matthew

2018-05-07

Infrared thermal desorption (IRTD) was coupled with direct analysis in real time mass spectrometry (DART-MS) for the detection of both inorganic and organic explosives from wipe collected samples. This platform generated discrete and rapid heating rates that allowed volatile and semivolatile organic explosives to thermally desorb at relatively lower temperatures, while still achieving elevated temperatures required to desorb nonvolatile inorganic oxidizer-based explosives. IRTD-DART-MS demonstrated the thermal desorption and detection of refractory potassium chlorate and potassium perchlorate oxidizers, compounds difficult to desorb with traditional moderate-temperature resistance-based thermal desorbers. Nanogram to sub-nanogram sensitivities were established for analysis of a range of organic and inorganic oxidizer-based explosive compounds, with further enhancement limited by the thermal properties of the most common commercial wipe materials. Detailed investigations and high-speed visualization revealed conduction from the heated glass-mica base plate as the dominant process for heating of the wipe and analyte materials, resulting in thermal desorption through boiling, aerosolization, and vaporization of samples. The thermal desorption and ionization characteristics of the IRTD-DART technique resulted in optimal sensitivity for the formation of nitrate adducts with both organic and inorganic species. The IRTD-DART-MS coupling and IRTD in general offer promising explosive detection capabilities to the defense, security, and law enforcement arenas.

Wipe-rinse technique for quantitating microbial contamination on large surfaces

Science.gov (United States)

Kirschner, L. E.; Puleo, J. R.

1979-01-01

The evaluation of an improved wipe-rinse technique for the bioassay of large areas was undertaken due to inherent inadequacies in the cotton swab-rinse technique to which assay of spacecraft is currently restricted. Four types of contamination control cloths were initially tested. A polyester-bonded cloth (PBC) was selected for further evaluation because of its superior efficiency and handling characteristics. Results from comparative tests with PBC and cotton swabs on simulated spacecraft surfaces indicated a significantly higher recovery efficiency for the PBC than for the cotton (90.4 versus 75.2%). Of the sampling area sites studied, PBC was found to be most effective on surface areas not exceeding 0.74 sq m (8.0 sq ft).

Purification of liquid products of cotton wipes biotransformation with the aid of Trichoderma viridae in orbital flight

Science.gov (United States)

Viacheslav, Ilyin; Korshunov, Denis

out the fermentation in space flight. For aerobic post-treatment of substrates remaining after biodegradation of cotton wipe there was selected a strain of the fungus Trihoderma viridae, able to grow at a slightly acid environment , and to bring the pH to neutral values. Bioreactor working volume of 40 ml, where 20 ml of liquid subjected to post-treatment was placed. Strain Trihoderma viridae, isolated from ISS environment, showed steady growth in terms identical to those of pre- cultivation. Efficiency of purification was assessed using the method of gas chromatography-mass spectrometry comparing the amount and concentration of the volatile organic compounds in the samples. It turned out that the number of compounds detected in the flight sample almost halved compared to the original sample obtained after biodegradation gauze anaerobic bacteria. The total concentration of volatile impurities dropped 6 times. Thus, despite the limited resource of oxygen, due to lack of aeration in the bioreactor strain Trihoderma viridae demonstrated the ability to perform aerobic purification of substrate obtained after anaerobic biodegradation of cotton wipes under orbital flight.

Evaluation of surface sampling method performance for Bacillus Spores on clean and dirty outdoor surfaces.

Energy Technology Data Exchange (ETDEWEB)

Wilson, Mollye C.; Einfeld, Wayne; Boucher, Raymond M.; Brown, Gary Stephen; Tezak, Matthew Stephen

2011-06-01

Recovery of Bacillus atrophaeous spores from grime-treated and clean surfaces was measured in a controlled chamber study to assess sampling method performance. Outdoor surfaces investigated by wipe and vacuum sampling methods included stainless steel, glass, marble and concrete. Bacillus atrophaeous spores were used as a surrogate for Bacillus anthracis spores in this study designed to assess whether grime-coated surfaces significantly affected surface sampling method performance when compared to clean surfaces. A series of chamber tests were carried out in which known amounts of spores were allowed to gravitationally settle onto both clean and dirty surfaces. Reference coupons were co-located with test coupons in all chamber experiments to provide a quantitative measure of initial surface concentrations of spores on all surfaces, thereby allowing sampling recovery calculations. Results from these tests, carried out under both low and high humidity conditions, show that spore recovery from grime-coated surfaces is the same as or better than spore recovery from clean surfaces. Statistically significant differences between method performance for grime-coated and clean surfaces were observed in only about half of the chamber tests conducted.

Wipes coated with a singlet-oxygen-producing photosensitizer are effective against human influenza virus but not against norovirus

NARCIS (Netherlands)

Verhaelen, Katharina; Bouwknegt, Martijn; Rutjes, Saskia; de Roda Husman, Ana Maria; Duizer, Erwin

2014-01-01

Transmission of enteric and respiratory viruses, including human norovirus (hNoV) and human influenza virus, may involve surfaces. In food preparation and health care settings, surfaces are cleaned with wipes; however, wiping may not efficiently reduce contamination or may even spread viruses,

Effect on skin hydration of using baby wipes to clean the napkin area of newborn babies: assessor-blinded randomised controlled equivalence trial.

Science.gov (United States)

Lavender, Tina; Furber, Christine; Campbell, Malcolm; Victor, Suresh; Roberts, Ian; Bedwell, Carol; Cork, Michael J

2012-06-01

Some national guidelines recommend the use of water alone for napkin cleansing. Yet, there is a readiness, amongst many parents, to use baby wipes. Evidence from randomised controlled trials, of the effect of baby wipes on newborn skin integrity is lacking. We conducted a study to examine the hypothesis that the use of a specifically formulated cleansing wipe on the napkin area of newborn infants (skin hydration when compared with using cotton wool and water (usual care). A prospective, assessor-blinded, randomised controlled equivalence trial was conducted during 2010. Healthy, term babies (n=280), recruited within 48 hours of birth, were randomly assigned to have their napkin area cleansed with an alcohol-free baby wipe (140 babies) or cotton wool and water (140 babies). Primary outcome was change in hydration from within 48 hours of birth to 4 weeks post-birth. Secondary outcomes comprised changes in trans-epidermal water loss, skin surface pH and erythema, presence of microbial skin contaminants/irritants at 4 weeks and napkin dermatitis reported by midwife at 4 weeks and mother during the 4 weeks. Complete hydration data were obtained for 254 (90.7 %) babies. Wipes were shown to be equivalent to water and cotton wool in terms of skin hydration (intention-to-treat analysis: wipes 65.4 (SD 12.4) vs. water 63.5 (14.2), p=0.47, 95% CI -2.5 to 4.2; per protocol analysis: wipes 64.6 (12.4) vs. water 63.6 (14.3), p=0.53, 95% CI -2.4 to 4.2). No significant differences were found in the secondary outcomes, except for maternal-reported napkin dermatitis, which was higher in the water group (p=0.025 for complete responses). Baby wipes had an equivalent effect on skin hydration when compared with cotton wool and water. We found no evidence of any adverse effects of using these wipes. These findings offer reassurance to parents who choose to use baby wipes and to health professionals who support their use. Current Controlled Trials ISRCTN86207019.

Identifying trace evidence in data wiping application software

Directory of Open Access Journals (Sweden)

Gregory H. Carlton

2012-06-01

Full Text Available One area of particular concern for computer forensics examiners involves situations in which someone utilized software applications to destroy evidence. There are products available in the marketplace that are relatively inexpensive and advertised as being able to destroy targeted portions of data stored within a computer system. This study was undertaken to identify these tools and analyze them to determine the extent to which each of the evaluated data wiping applications perform their tasks and to identify trace evidence, if any, left behind on disk media after executing these applications. We evaluated five Windows 7 compatible software products whose advertised features include the ability for users to wipe targeted files, folders, or evidence of selected activities. We conducted a series of experiments that involved executing each application on systems with identical data, and we then analyzed the results and compared the before and after images for each application. We identified information for each application that is beneficial to forensics examiners when faced with similar situations. This paper describes our application selection process, our application evaluation methodology, and our findings. Following this, we describe limitations of this study and suggest areas of additional research that will benefit the study of digital forensics.

Effect on skin hydration of using baby wipes to clean the napkin area of newborn babies: assessor-blinded randomised controlled equivalence trial

OpenAIRE

Lavender, Tina; Furber, Christine; Campbell, Malcolm; Victor, Suresh; Roberts, Ian; Bedwell, Carol; Cork, Michael J

2012-01-01

Abstract Background Some national guidelines recommend the use of water alone for napkin cleansing. Yet, there is a readiness, amongst many parents, to use baby wipes. Evidence from randomised controlled trials, of the effect of baby wipes on newborn skin integrity is lacking. We conducted a study to examine the hypothesis that the use of a specifically formulated cleansing wipe on the napkin area of newborn infants (

Experimental skin deposition of chromium on the hands following handling of samples of leather and metal

DEFF Research Database (Denmark)

Bregnbak, David; Thyssen, Jacob P.; Jellesen, Morten Stendahl

2016-01-01

Background: Chromium is an important skin sensitizer. Exposure to it has been regulated in cement, and recently in leather. Studies on the deposition of chromium ions on the skin as a result of handling different chromium-containing materials are sparse, but could improve the risk assessment...... of contact sensitization and allergic contact dermatitis caused by chromium. Objectives: To determine whether the handling of chromium-containing samples of leather and metal results in the deposition of chromium onto the skin. Methods: Five healthy volunteers participated. For 30 min, they handled samples...... of leather and metal known to contain and release chromium. Skin deposition of chromium was assessed with the acid wipe sampling technique. Results: Acid wipe sampling of the participants' fingers showed chromium deposition on the skin in all participants who had been exposed to leather (range 0.01–0.20 µg...

Potential Allergens in Disposable Diaper Wipes, Topical Diaper Preparations, and Disposable Diapers: Under-recognized Etiology of Pediatric Perineal Dermatitis.

Science.gov (United States)

Yu, JiaDe; Treat, James; Chaney, Keri; Brod, Bruce

2016-01-01

Allergic contact dermatitis in young children may be an under-recognized cause of perineal dermatitis. The diapered infant skin is uniquely susceptible to allergic contact dermatitis because of more permeable neonatal skin, a moist environment, frequent contact with irritants and resultant skin barrier breakdown, and exposure to topical products such as diaper wipes, diaper preparations, and disposable diapers. To our knowledge, potential allergens in these products have not been thoroughly catalogued or studied. We explore and review potential allergenic ingredients in diaper wipes, topical diaper preparations, and disposable diapers. We analyzed 63 diaper wipes, 41 topical diaper preparations, and the 3 top selling diaper brands available from two of the largest retailers in the United States. Each potential allergen is discussed, and epidemiologic studies of rates of sensitization to potential allergens in children are also reported. Botanical extracts, including members of the Compositae family, were the most commonly represented potential allergen in both diaper wipes and topical preparations. Other potential allergens identified with high frequency include α-tocopherol, fragrances, propylene glycol, parabens, iodopropynyl butylcarbamate, and lanolin. Frequent culprits such as formaldehyde releasers and methylchloroisothiazolinone/methylisothiazolinone were not prevalent in our analyzed products.

Putting evaporators to work: wiped film evaporator for high level wastes

International Nuclear Information System (INIS)

Dierks, R.D.; Bonner, W.F.

1976-01-01

At Battelle, Pacific Northwest Laboratories, a pilot scale, wiped film evaporator was tested for concentrating high level liquid wastes from Purex-type nuclear fuel recovery processes. The concentrates produced up to 60 wt-percent total solids; and the simplicity of operation and design of the evaporator gave promise for low maintenance and high reliability

40 CFR 761.312 - Compositing of samples.

Science.gov (United States)

2010-07-01

... to composite surface wipe test samples and to use the composite measurement to represent the PCB concentration of the entire surface. Composite samples consist of more than one sample gauze extracted and... arithmetic mean of the composited samples. (a) Compositing samples from surfaces to be used or reused. For...

Results of Testing the Relative Oxidizing Hazard of Wipes and KMI Zeolite

Energy Technology Data Exchange (ETDEWEB)

Ams, Bridget Elaine [Los Alamos National Laboratory

2017-05-09

This report includes the results from testing performed on the relative oxidizing hazard of a number of organic sorbing wipe materials, as well as KMI zeolite. These studies were undertaken to address a need by the Los Alamos National Laboratory (LANL) Hazardous Materials Management group, which requires a material that can sorb small spills in a glovebox without creating a disposal hazard due to the potential for oxidation reactions, as requested in Request for Testing of Wipes and Zeolite for Los Alamos National Laboratory Hazardous Materials Group (NPl-7) (NPl-7-17-002) and Request for Testing of Chamois Material for Los Alamos National Laboratory Hazardous Materials Group (NPl-7) (NPl-7-17-005). This set oftests is a continuation of previous testing described in Results from Preparation and Testing of Sorbents Mixed with (DWT-RPT-003), which provided data for the Waste Isolation Pilot Plant's Basis of Knowledge. The Basis of Knowledge establishes criteria for evaluating transuranic (TRU) waste that contains oxidizing chemicals.

Comparison of Two Surface Contamination Sampling Techniques Conducted for the Characterization of Two Pajarito Site Manhattan Project National Historic Park Properties

Energy Technology Data Exchange (ETDEWEB)

Lopez, Tammy Ann [Montana Tech of the Univ. of Montana, Butte, MT (United States); Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2016-07-29

Technical Area-18 (TA-18), also known as Pajarito Site, is located on Los Alamos National Laboratory property and has historic buildings that will be included in the Manhattan Project National Historic Park. Characterization studies of metal contamination were needed in two of the four buildings that are on the historic registry in this area, a “battleship” bunker building (TA-18-0002) and the Pond cabin (TA-18-0029). However, these two buildings have been exposed to the elements, are decades old, and have porous and rough surfaces (wood and concrete). Due to these conditions, it was questioned whether standard wipe sampling would be adequate to detect surface dust metal contamination in these buildings. Thus, micro-vacuum and surface wet wipe sampling techniques were performed side-by-side at both buildings and results were compared statistically. A two-tail paired t-test revealed that the micro-vacuum and wet wipe techniques were statistically different for both buildings. Further mathematical analysis revealed that the wet wipe technique picked up more metals from the surface than the microvacuum technique. Wet wipes revealed concentrations of beryllium and lead above internal housekeeping limits; however, using an yttrium normalization method with linear regression analysis between beryllium and yttrium revealed a correlation indicating that the beryllium levels were likely due to background and not operational contamination. PPE and administrative controls were implemented for National Park Service (NPS) and Department of Energy (DOE) tours as a result of this study. Overall, this study indicates that the micro-vacuum technique may not be an efficient technique to sample for metal dust contamination.

Development of automatic smear testing sampler for radioactive contamination of floor in nuclear power plant

International Nuclear Information System (INIS)

Nozawa, Katsuro; Hashimoto, Hiroshi; Shinohara, Yohtaro; Iwaki, Kiyotaka

1980-01-01

The floor contamination with radioactive substances in the controlled area of nuclear power stations is strictly controlled, and it is tested by the smear method, wiping the contaminants on floors with filter papers or cloths and measuring the radioactive intensity to obtain contamination density. The works are very laborious, therefore the automatic smear sampler was developed. Simple operation, shortening of time required for wiping, constant and high efficiency of wiping, and easy numbering of samples were the aims in the development. The method of wiping, the mechanisms of wiping, cloth feeding and running, the surface pressure at the time of wiping, the number of times of wiping and required motor torque were studied. The outline of the developed sampler is explained. The performance of the sampler was compared with manual wiping. The efficiency of wiping with the sampler was 92%, assuming manual wiping as 100. Difference was not observed between careful manual wiping and the wiping with the sampler, therefore it was confirmed that this automatic floor smear sampler can be put in practical use. By conventional manual sampling, the maximum limit was about 400 samples/man-day, but when this sampler is used, about 1000 samples/sampler-day is possible. At present, this sampler is operated in Hamaoka Nuclear Power Station. (Kako, I.)

Air and Surface Sampling Method for Assessing Exposures to Quaternary Ammonium Compounds Using Liquid Chromatography Tandem Mass Spectrometry.

Science.gov (United States)

LeBouf, Ryan F; Virji, Mohammed Abbas; Ranpara, Anand; Stefaniak, Aleksandr B

2017-07-01

This method was designed for sampling select quaternary ammonium (quat) compounds in air or on surfaces followed by analysis using ultraperformance liquid chromatography tandem mass spectrometry. Target quats were benzethonium chloride, didecyldimethylammonium bromide, benzyldimethyldodecylammonium chloride, benzyldimethyltetradecylammonium chloride, and benzyldimethylhexadecylammonium chloride. For air sampling, polytetrafluoroethylene (PTFE) filters are recommended for 15-min to 24-hour sampling. For surface sampling, Pro-wipe® 880 (PW) media was chosen. Samples were extracted in 60:40 acetonitrile:0.1% formic acid for 1 hour on an orbital shaker. Method detection limits range from 0.3 to 2 ng/ml depending on media and analyte. Matrix effects of media are minimized through the use of multiple reaction monitoring versus selected ion recording. Upper confidence limits on accuracy meet the National Institute for Occupational Safety and Health 25% criterion for PTFE and PW media for all analytes. Using PTFE and PW analyzed with multiple reaction monitoring, the method quantifies levels among the different quats compounds with high precision (detection limits to capture quats on air sampling filters with only a 15-min sample duration with a maximum assessed storage time of 103 days before sample extraction. This method will support future exposure assessment and quantitative epidemiologic studies to explore exposure-response relationships and establish levels of quats exposures associated with adverse health effects. © The Author 2017. Published by Oxford University Press on behalf of the British Occupational Hygiene Society.

Final Rule: 2013 Conditional Exclusions From Solid Waste and Hazardous Waste for Solvent-Contaminated Wipes

Science.gov (United States)

This is a regulation page for the final rule EPA issued on July 31, 2013 that modifies the hazardous waste management regulations for solvent-contaminated wipes under the Resource Conservation and Recovery Act (RCRA).

Development of floor smear sampler (floor radioactive contamination measuring instrument) for nuclear facilities

International Nuclear Information System (INIS)

Miyagawa, Minoru; Ito, Haruo; Nozawa, Katsuro; Shinohara, Yotaro; Hashimoto, Hiroshi.

1980-01-01

The control of the floor contamination with radioactive substances in nuclear facilities is strictly carried out by smear method, in which the contaminants on floor surfaces are wiped off with filter papers or cloths, and the contamination density on the floor surfaces is measured through their intensity of radioactivity. This wiping work is laborious since it is carried out in leaning-over posture when many samples must be taken in wide floor area. Therefore, to achieve labor saving in this work, an automatic sampler was developed. In the floor smear sampler developed, samples are taken on long band type wiping cloths only by handle operation, and the sample numbers are printed. When many samples are taken in wide floor area, this is especially effective, and the labor saving by 1/3 to 1/2 can be achieved. At present, this sampler is put in practical use in Hamaoka Nuclear Power Station. At the time of trial manufacture, the method of wiping, the mechanisms of wiping, cloth feeding and running, the contact pressure and the number of times of wiping affecting wiping efficiency and the required torque of a motor were examined. The developed sampler is that of constant contact pressure, vibration wiping type, and the rate of sampling is 10 sec per one sample. 100 samples can be taken on one roll of wiping cloth. The results of performance test are reported. (Kako, I.)

Determination of Glucocorticoids in UPLC-MS in Environmental Samples from an Occupational Setting

Directory of Open Access Journals (Sweden)

Enrico Oddone

2015-01-01

Full Text Available Occupational exposures to glucocorticoids are still a neglected issue in some work environments, including pharmaceutical plants. We developed an analytical method to quantify simultaneously 21 glucocorticoids using UPLC coupled with mass spectrometry to provide a basis to carry out environmental monitoring. Samples were taken from air, hand-washing tests, pad-tests and wipe-tests. This paper reports the contents of the analytical methodology, along with the results of this extensive environmental and personal monitoring of glucocorticoids. The method in UPLC-MS turned out to be suitable and effective for the aim of the study. Wipe-test and pad-test desorption was carried out using 50 mL syringes, a simple technique that saves time without adversely affecting analyte recovery. Results showed a widespread environmental pollution due to glucocorticoids. This is of particular concern. Evaluation of the dose absorbed by each worker and identification of a biomarker for occupational exposure will contribute to assessment and prevention of occupational exposure.

A Cultural Look at Moral Purity: Wiping the Face Clean

Directory of Open Access Journals (Sweden)

Spike W. S. eLee

2015-05-01

Full Text Available Morality is associated with bodily purity in the custom of many societies. Does that imply moral purity is a universal psychological phenomenon? Empirically, it has never been examined, as all prior experimental data came from Western samples. Theoretically, we suggest the answer is not so straightforward—it depends on the kind of universality under consideration. Combining perspectives from cultural psychology and embodiment, we predict a culture-specific form of moral purification. Specifically, given East Asians’ emphasis on the face as a representation of public self-image, we hypothesize that facial purification should have particularly potent moral effects in a face culture. Data show that face-cleaning (but not hands-cleaning reduces guilt and regret most effectively against a salient East Asian cultural background. It frees East Asians from guilt-driven prosocial behavior. In the wake of their immorality, they find a face-cleaning product especially appealing and spontaneously choose to wipe their face clean. These patterns highlight both culturally variable and universal aspects of moral purification. They further suggest an organizing principle that informs the vigorous debate between embodied and amodal perspectives.

Wiping frictional properties of electrospun hydrophobic/hydrophilic polyurethane nanofiber-webs on soda-lime glass and silicon-wafer.

Science.gov (United States)

Watanabe, Kei; Wei, Kai; Nakashima, Ryu; Kim, Ick Soo; Enomoto, Yuji

2013-04-01

In the present work, we conducted the frictional tests of hydrophobic and hydrophilic polyurethane (PUo and PUi) nanofiber webs against engineering materials; soda-lime glass and silicon wafer. PUi/glass combination, with highest hydrophilicity, showed the highest friction coefficient which decrease with the increase of the applied load. Furthermore, the effects of fluorine coating are also investigated. The friction coefficient of fluorine coated hydrophobic PU nanofiber (PUof) shows great decrease against the silicon wafer. Finally, wiping ability and friction property are investigated when the substrate surface is contaminated. Nano-particle dusts are effectively collected into the pores by wiping with PUo and PUi nanofiber webs both on glass and silicon wafer. The friction coefficient gradually increased with the increase of the applied load.

Preliminary assessment on exposure of four typical populations to potentially toxic metals by means of skin wipes under the influence of haze pollution.

Science.gov (United States)

Cao, Zhiguo; Wang, Mengmeng; Chen, Qiaoying; Zhang, Yajie; Dong, Wenjing; Yang, Tianfang; Yan, Guangxuan; Zhang, Xin; Pi, Yunqing; Xi, Benye; Bu, Qingwei

2018-02-01

To investigate the exposure risk of human beings to nine potentially toxic metals (PTMs), namely, Cu, Cr, Zn, As, Cd, Pb, Ni, Mn, and Co, skin wipe samples were collected from four types of populations, namely, children, undergraduates, security guards, and professional drivers, under different haze pollution levels in Xinxiang, China by using Ghost wipes. The Ghost wipes were quantitatively analyzed by inductively coupled plasma mass spectrometry (ICP-MS) after microwave digestion. Generally, Zn (ND-1350μg/m 2 for undergraduates, ND-2660μg/m 2 for security guards, ND-2460μg/m 2 for children, and ND-2530μg/m 2 for professional drivers) showed the highest concentration among the four populations, followed by Cu (0.02-83.4μg/m 2 for undergraduates, ND-70.2μg/m 2 for security guards, 23.2-487μg/m 2 for children, and ND-116μg/m 2 for professional drivers). As (ND-5.7μg/m 2 for undergraduates, ND-2.3μg/m 2 for security guards, ND-21.1μg/m 2 for children, and ND-11.0μg/m 2 for professional drivers) and Co (ND-6.0μg/m 2 for undergraduates, ND-7.9μg/m 2 for security guards, ND-13.4μg/m 2 for children, and ND-2.1μg/m 2 for professional drivers) showed the lowest concentrations in all populations. Remarkable differences were found among the four populations and PTM levels decreased in the following order: children, professional drivers, security guards, and undergraduates. Gender variation was discovered for undergraduates and children. Generally, PTM contamination in skin wipes collected during a light haze pollution level was generally higher than that during a heavy haze pollution level, but PTM contamination was comparable between the two haze pollution levels for children. Non-carcinogenic exposure risks to As, Cd, and Pb for all populations were higher than those for the other six elements but all of them were within the acceptable safety threshold, indicating no apparent non-carcinogenic risk. Copyright © 2017 Elsevier B.V. All rights reserved.

EPA Method 8321B (SW-846): Solvent-Extractable Nonvolatile Compounds by High Performance Liquid Chromatography-Thermospray-Mass Spectrometry (HPLC-TS-MS) or Ultraviolet (UV) Detection

Science.gov (United States)

Method 8321B describes procedures for preparation and analysis of solid, aqueous liquid, drinking water and wipe samples using high performance liquid chromatography and mass spectrometry for extractable non-volatile compounds.

Cyclophosphamide identification in wipe test by GC-MS and solid phase extraction Identificação de ciclofosfamida em wipe teste por CG-EM com prévia extração em fase sólida

Directory of Open Access Journals (Sweden)

Isarita Martins

2004-03-01

Full Text Available In this study cyclophosphamide was quantified after adapting a prior analytical method using gas chromatography-mass spectrometry after solid phase purification and derivatization with trifluoroacetic anhydride. The analyte was measured by analysis in wipe test from infusion bags, which may be contaminated by contact with the gloves used during preparation of the drugs. Surface of bag contaminated may be an important source of contamination for workers in the others chemoterapy handling areas, such as administration rooms. This drug, in fact, is one of the most frequently used alkylating antineoplastic agents for different types of tumors and it is furthermore classified as a human carcinogen by IARC. Ifosfamide was used as internal standard and the quantification was carried out by reference to calibration curves within a range from 1 to 100 ng/mL. The limit of detection was 0.4 ng/mL. The values of the variation coefficient varied from 0.5 to 10% (intra-assay and from 0 to 19% (interassay. Frozen reference wipe samples containing cyclophosphamide were analysed over one month and no significant loss was observed. The range obtained for bias assay was 83-116% and the recovery was 98.9%. Cyclophosphamide was measured in 36 of 42 infusion bags collected from different hospitals with values ranging from 90 to 41874 ng (median= 607.5 ng. The results, well related to those reported in the literature, suggest that this method can be used to identify cyclophosphamide from wipe samples and can be considered useful in exposure assessment to this drug.A ciclofosfamida é uma agente alquilante freqüentemente utilizado na prática clínica para diferentes tipos de tumores e, é classificado como carcinógeno para humanos pelo IARC. Neste estudo, o fármaco foi quantificado, após adaptação de um método analítico, utilizando a cromatografia gasosa acoplada à espectrometria de massa com prévia extração em fase sólida e derivação com anidrido

Estimating dermal transfer from PCB-contaminated porous surfaces.

Science.gov (United States)

Slayton, T M; Valberg, P A; Wait, A D

1998-06-01

Health risks posed by dermal contact with PCB-contaminated porous surfaces have not been directly demonstrated and are difficult to estimate indirectly. Surface contamination by organic compounds is commonly assessed by collecting wipe samples with hexane as the solvent. However, for porous surfaces, hexane wipe characterization is of limited direct use when estimating potential human exposure. Particularly for porous surfaces, the relationship between the amount of organic material collected by hexane and the amount actually picked up by, for example, a person's hand touch is unknown. To better mimic PCB pickup by casual hand contact with contaminated concrete surfaces, we used alternate solvents and wipe application methods that more closely mimic casual dermal contact. Our sampling results were compared to PCB pickup using hexane-wetted wipes and the standard rubbing protocol. Dry and oil-wetted samples, applied without rubbing, picked up less than 1% of the PCBs picked up by the standard hexane procedure; with rubbing, they picked up about 2%. Without rubbing, saline-wetted wipes picked up 2.5%; with rubbing, they picked up about 12%. While the nature of dermal contact with a contaminated surface cannot be perfectly reproduced with a wipe sample, our results with alternate wiping solvents and rubbing methods more closely mimic hand contact than the standard hexane wipe protocol. The relative pickup estimates presented in this paper can be used in conjunction with site-specific PCB hexane wipe results to estimate dermal pickup rates at sites with PCB-contaminated concrete.

The Impact of Feet Callosities, Arm Posture, and Usage of Electrolyte Wipes on Body Composition by Bioelectrical Impedance Analysis in Morbidly Obese Adults.

Science.gov (United States)

Roekenes, Jessica; Strømmen, Magnus; Kulseng, Bård; Martins, Catia

2015-01-01

This study evaluated the impact of feet callosities, arm posture, and use of electrolyte wipes on body composition measurements by bioelectrical impedance analysis (BIA) in morbidly obese adults. 36 morbidly obese patients (13 males, aged 28-70 years, BMI 41.6 ± 4.3 kg/m2) with moderate/severe feet callosities participated in this study. Body composition (percent body fat (%BF)) was measured while fasting using multi-frequency BIA (InBody 720®), before and after removal of callosities, with and without InBody® electrolyte wipes and custom-built auxiliary pads (to assess arm posture impact). Results from BIA were compared to air displacement plethysmography (ADP, BodPod®). Median %BF was significantly higher with auxiliary pads than without (50.1 (interquartile range 8.2) vs. 49.3 (interquartile range 9.1); p interquartile range 9.1) vs. 50.0 (interquartile range 7.9); NS) or use of wipes (49.6 (interquartile range 8.5) vs. 49.3 (interquartile range 9.1); NS). No differences in %BF were found between BIA and ADP (49.1 (IQR: 8.9) vs. 49.3 (IQR: 9.1); NS). Arm posture has a significant impact on %BF assessed by BIA, contrary to the presence of feet callosities and use of electrolyte wipes. Arm posture standardization during BIA for body composition assessment is, therefore, recommended. © 2015 S. Karger GmbH, Freiburg.

78 FR 46447 - Conditional Exclusions From Solid Waste and Hazardous Waste for Solvent-Contaminated Wipes

Science.gov (United States)

2013-07-31

... section 307 of the Clean Water Act (CWA)); A municipal solid waste landfill that is regulated under 40 CFR... laundries and dry cleaners could dispose of sludge from cleaning solvent-contaminated wipes in solid waste landfills if the sludge does not exhibit a hazardous waste characteristic. \\8\\ The Agency stated in the...

EXPERIMENTAL COMPARISON OF THE AEROSOL METHOD OF DISINFECTION OF AIR AND SURFACES CONTAMINATED BY M. TUBERCULOSIS

Directory of Open Access Journals (Sweden)

V. V. Kuzin

2018-01-01

Full Text Available The objective of the study: to analyze efficiency of an aerosol method of M. tuberculosis deactivation in the air and on surfaces versus the conventional methods of the disinfectants' application.Subjects and Methods. The article describes the evaluation of efficiency of the aerosol method of M. tuberculosis, H37Rv strain, deactivation on surfaces (tested objects made of linoleum and in the air using the disinfectant of Green Dez based on chlorine dioxide versus deactivation through wiping and irrigation.The efficiency of disinfectant was tested by the device of 099С А4224 manufactured by Glas-Col, USA, using the air sampler of PU-1B, Russia.The Mobile Hygienic Center (MNC, Russia, was used for application of the disinfectant, wiping and irrigation was done using the disperser of Avtomaks AO-2, Russia.The bacterial aerosol was generated in the Glass-Col chamber with the concentration 5 ± 2.5 × 102 CFU/cm3, by spraying the suspension of M. tuberculosis, H37Rv strain. After that, the disinfectant spray was supplied to the chamber, where linoleum objects were placed horizontally on a variety of surfaces. In order to evaluate efficiency of surface treatment by wiping, the test objects were wiped with a tissue, soaked with the solution of Green Dez, based on consumption of 100-150 ml/m2. In 15, 30 and 60 minutes, the samples of inactivated M. tuberculosis aerosol were collected using an aspirator, chambers with test objects were closed and placed in the vent hood. To monitor efficiency of disinfection of the test object surfaces, the rinse blanks were done by wiping the surface with a sterile gauze wad, soaked with 0.5% of sodium thiosulfate solution.The samples of deactivated aerosol and rinse blanks from the surfaces of test objects were put into Petri dishes with Middlebrook 7H11 medium. The cultures were incubated in the thermostat at the temperature of 37 ± 1° C for 10-21 days, and the number of colonies was counted.Sterile water was used

Wiping Out Disadvantages: The Programs and Services Needed To Supplement Regular Education for Poor School Children.

Science.gov (United States)

Education Law Center, Inc., Newark, NJ.

In "Abbott v. Burke" the New Jersey Supreme Court determined that the state constitutional guarantee to a thorough and efficient education must include a supplemental program designed to wipe out the deficits poor children bring with them to school. In this report, the Education Law Center draws on educational research to identify the…

Sample collection of virulent and non-virulent B. anthracis and Y. pestis for bioforensics analysis

Energy Technology Data Exchange (ETDEWEB)

Hong-geller, Elizabeth [Los Alamos National Laboratory; Valdez, Yolanda E [Los Alamos National Laboratory; Shou, Yulin [Los Alamos National Laboratory; Yoshida, Thomas M [Los Alamos National Laboratory; Marrone, Babetta L [Los Alamos National Laboratory; Dunbar, John [Los Alamos National Laboratory

2009-01-01

Validated sample collection methods are needed for recovery of microbial evidence in the event of accidental or intentional release of biological agents into the environment. To address this need, we evaluated the sample recovery efficiencies of two collection methods -- swabs and wipes -- for both non-virulent and virulent strains of B. anthracis and Y. pestis from four types of non-porous surfaces: two hydrophilic surfaces, stainless steel and glass, and two hydrophobic surfaces, vinyl and plastic. Sample recovery was quantified using Real-time qPCR to assay for intact DNA signatures. We found no consistent difference in collection efficiency between swabs or wipes. Furthermore, collection efficiency was more surface-dependent for virulent strains than non-virulent strains. For the two non-virulent strains, B. anthracis Sterne and Y. pestis A1122, collection efficiency was approximately 100% and 1 %, respectively, from all four surfaces. In contrast, recovery of B. anthracis Ames spores and Y. pestis C092 from vinyl and plastic was generally lower compared to collection from glass or stainless steel, suggesting that surface hydrophobicity may playa role in the strength of pathogen adhesion. The surface-dependent collection efficiencies observed with the virulent strains may arise from strain-specific expression of capsular material or other cell surface receptors that alter cell adhesion to specific surfaces. These findings contribute to validation of standard bioforensics procedures and emphasize the importance of specific strain and surface interactions in pathogen detection.

Hand hygiene with soap and water is superior to alcohol rub and antiseptic wipes for removal of Clostridium difficile.

Science.gov (United States)

Oughton, Matthew T; Loo, Vivian G; Dendukuri, Nandini; Fenn, Susan; Libman, Michael D

2009-10-01

To evaluate common hand hygiene methods for efficacy in removing Clostridium difficile. Randomized crossover comparison among 10 volunteers with hands experimentally contaminated by nontoxigenic C. difficile. Interventions included warm water with plain soap, cold water with plain soap, warm water with antibacterial soap, antiseptic hand wipes, alcohol-based handrub, and a control involving no intervention. All interventions were evaluated for mean reduction in colony-forming units (CFUs) under 2 contamination protocols: "whole hand" and "palmar surface." Results were analyzed according to a Bayesian approach, by using hierarchical models adjusted for multiple observations. Under the whole-hand protocol, the greatest adjusted mean reductions were achieved by warm water with plain soap (2.14 log(10) CFU/mL [95% credible interval (CrI), 1.74-2.54 log(10) CFU/mL]), cold water with plain soap (1.88 log(10) CFU/mL [95% CrI, 1.48-2.28 log(10) CFU/mL), and warm water with antibacterial soap (1.51 log(10) CFU/mL [95% CrI, 1.12-1.91 log(10) CFU/mL]), followed by antiseptic hand wipes (0.57 log(10) CFU/mL [95% CrI, 0.17-0.96 log(10) CFU/mL]). Alcohol-based handrub (0.06 log(10) CFU/mL [95% CrI, -0.34 to 0.45 log(10) CFU/mL]) was equivalent to no intervention. Under the palmar surface protocol, warm water with plain soap, cold water with plain soap, and warm water with antibacterial soap again yielded the greatest mean reductions, followed by antiseptic hand wipes (26.6, 26.6, 26.6, and 21.9 CFUs per plate, respectively), when compared with alcohol-based handrub. Hypothenar (odds ratio, 10.98 [95% CrI, 1.96-37.65]) and thenar (odds ratio, 6.99 [95% CrI, 1.25-23.41]) surfaces were more likely than fingertips to remain heavily contaminated after handwashing. Handwashing with soap and water showed the greatest efficacy in removing C. difficile and should be performed preferentially over the use of alcohol-based handrubs when contact with C. difficile is suspected or likely.

Noninvasive method for the assessment of dermal uptake of pesticides using attenuated total reflectance infrared spectroscopy.

Science.gov (United States)

Carden, Angela; Yost, Michael G; Fenske, Richard A

2005-03-01

Dermal absorption of pesticides is a primary exposure route for agricultural workers, but is not well characterized. Current measurement techniques are either invasive, such as tape-stripping, or require extensive sample preparation or analysis time, such as urinary metabolite monitoring or wipe sampling followed by gas chromatography analysis. We present the application of a noninvasive, spectroscopic approach for the measurement of pesticide absorption into skin. Attenuated total reflectance infrared spectroscopy (ATR-IR) was used to monitor directly the absorption of two pesticides--captan and azinphos-methyl--in ten volunteers over 20 min under occlusive conditions. We found substantial variability in absorption across subjects. Our results were comparable to those measured by the more traditional method of wipe-sampling followed by extraction and gas chromatography analysis. Multivariate data analysis, in the form of multivariate curve resolution (MCR), is a novel addition to this type of experiment, yielding time-resolved information unachievable by standard methods. These data are potentially more informative than the monitoring of blood or urinary metabolites because they can be acquired in essentially real-time, allowing observations of pesticide absorption on a rapid timescale rather than over hours or days.

DESI-MS2: a rapid and innovative method for trace analysis of six cytostatic drugs in health care setting.

Science.gov (United States)

Fabrizi, Giovanni; Fioretti, Marzia; Rocca, Lucia Mainero; Curini, Roberta

2012-05-01

With the aim of establishing exposure levels for hospital personnel preparing and administering cytostatic drugs (CDs), here, we present an innovative screening method based on the use of the desorption electrospray ionization (DESI) interface coupled with a hybrid quadrupole linear ion trap mass spectrometer. A rapid, simple, and sensitive procedure was developed for the simultaneous surface monitoring of cyclophosphamide, dacarbazine, methotrexate, vincristine, gemcitabine, and cytarabine. Since analytes were in the solid state, a novel approach based on the use of passive samplers was combined with the direct analysis of wipes. A PTFE-printed glass slide was used as a passive sampler, while hydrophobic centers of Swiffer® cloths were judged extremely efficient as wipe samplers. After the sampling period, the CD collectors were directly processed with the DESI-MS system without any further treatment. MS/MS confirmatory analysis was conducted using selected reaction monitoring in the positive ion mode and detection limits were evaluated. Values were at the picograms per square millimeter levels on the passive collector and at the picograms per square centimeter levels for the wipe ones. Direct determination on solid-state samples combined with mass spectrometry selectivity provided a powerful tool so far unapplied to occupational hygiene.

Performance of a wiped film evaporator with simulated high level waste slurries

International Nuclear Information System (INIS)

Dierks, R.D.; Bonner, W.F.

1975-01-01

The horizontal, reverse taper, wiped film evaporator that was evaluated demonstrated a number of positive characteristics with respect to its applicability in the solidification of nuclear fuel recovery process wastes. Foremost among these is its ability to remove the bulk (80 to 90 percent) of the liquid associated with any of the purex-type high level, intermediate level, or mixed waste slurries. The major disadvantage of the evaporator is its current inability to discharge a product that is low enough in liquid content to avoid sticking to the evaporator discharge nozzle. Also, while the indirect indications of the torque required to turn the rotor and the power drawn by the drive motor are indicative of the liquid content of the discharged product, no reliable correlation has been found to cover all of the possible flow rates and feed stock compositions that the evaporator may be required to handle. In addition, no reliable means has been found to indicate the presence or absence of product flow through the discharge nozzle. The lack of a positive means of moving the product concentrate out of the evaporator and into a high temperature receiver is an undesirable feature of the evaporator. Pulverized glass former, or frit, was added to the evaporator feedstock in a ratio of frit to metal oxides of 2 to 1, and the resulting mixture successfully evaporated to a concentrate containing about 50 percent solids. In general, the performance of the wiped film evaporator evaluated was favorable for its use in a nuclear waste fixation process, however further development of the rotor design, power input, and operating techniques will be required to produce a free flowing solid product

40 CFR 761.306 - Sampling 1 meter square surfaces by random selection of halves.

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Sampling 1 meter square surfaces by...(b)(3) § 761.306 Sampling 1 meter square surfaces by random selection of halves. (a) Divide each 1 meter square portion where it is necessary to collect a surface wipe test sample into two equal (or as...

Differences of detection efficiency among several nasal swab samples simulated for nuclear emergency accident

International Nuclear Information System (INIS)

Fukutsu, Kumiko; Yamada, Yuji; Kurihara, Osamu; Akashi, Makoto; Momose, Takumaro; Miyabe, Kenjiro

2008-01-01

At nuclear emergency accident such as inhalation intake of alpha nuclide, an indispensable nasal swab method has not been used for the precise internal dose estimation. One of the reasons is uncertainty in its radiation measurement, so that precise measurement with alpha spectrometry was examined for filter samples simulating nasal swab. It was confirmed that the alpha spectrometry made possible the distinction between solution and particulate in addition to the nuclide identification. The alpha activity in swab sample was precisely evaluated only when the detection efficiency was determined considering the self-absorption with filter fibers. Another big problem of wiping efficiency in nasal swabbing is still remain, but this study certainly raised the usefulness of the nasal swab method for rapid response in emergency. (author)

Experimental estimation of migration and transfer of organic substances from consumer articles to cotton wipes: Evaluation of underlying mechanisms

NARCIS (Netherlands)

Clausen, P.A.; Spaan, S.; Brouwer, D.H.; Marquart, H.; Feber, M. le; Engel, R.; Geerts, L.; Jensen, K.A.; Kofoed-Sørensen, V.; Hansen, B.; Brouwere, K. de

2016-01-01

The aim of this work was to identify the key mechanisms governing transport of organic chemical substances from consumer articles to cotton wipes. The results were used to establish a mechanistic model to improve assessment of dermal contact exposure. Four types of PVC flooring, 10 types of textiles

Analysis of alcohol-based hand sanitizer delivery systems: efficacy of foam, gel, and wipes against influenza A (H1N1) virus on hands.

Science.gov (United States)

Larson, Elaine L; Cohen, Bevin; Baxter, Kathleen A

2012-11-01

Minimal research has been published evaluating the effectiveness of hand hygiene delivery systems (ie, rubs, foams, or wipes) at removing viruses from hands. The purposes of this study were to determine the effect of several alcohol-based hand sanitizers in removing influenza A (H1N1) virus, and to compare the effectiveness of foam, gel, and hand wipe products. Hands of 30 volunteers were inoculated with H1N1 and randomized to treatment with foam, gel, or hand wipe applied to half of each volunteer's finger pads. The log(10) count of each subject's treated and untreated finger pads were averaged. Log(10) reductions were calculated from these differences and averaged within treatment group. Between-treatment analysis compared changes from the untreated finger pads using analysis of covariance with treatment as a factor and the average log(10) untreated finger pads as the covariate. Log(10) counts on control finger pads were 2.7-5.3 log(10) of the 50% infectious dose for tissue culture (TCID(50)/0.1 mL) (mean, 3.8 ± 0.5 log(10) TCID(50)/0.1 mL), and treated finger pad counts for all test products were 0.5-1.9 log(10) TCID(50)/0.1 mL (mean, 0.53 ± 0.17 log(10) TCID(50)/0.1 mL). Treatments with all products resulted in a significant reduction in viral titers (>3 logs) at their respective exposure times that were statistically comparable. All 3 delivery systems (foam, gel, and wipe) produced significantly reduced viral counts on hands. Copyright © 2012 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Mosby, Inc. All rights reserved.

Concentration of Melton Valley Storage Tank surrogates with a wiped film evaporator

International Nuclear Information System (INIS)

Boring, M.D.; Farr, L.L.; Fowler, V.L.; Hewitt, J.D.

1994-08-01

This report describes experiments to determine whether a wiped film evaporator (WFE) might be used to concentrate low-level liquid radioactive waste (LLLW). Solutions used in these studies were surrogates that contain no radionuclides. The compositions of the surrogates were based on one of Oak Ridge National Laboratory's (ORNL's) Melton Valley Storage Tanks (MVSTs). It was found that a WFE could be used to concentrate LLLW to varying degrees by manipulating various parameters. The parameters studied were rotor speed, process fluid feed temperature and feed rate, and evaporator temperature. Product consistency varied from an unsaturated liquid to a dry powder. Volume reductions up to 68% were achieved. System decontamination factors were consistently in the range of 10 4

Arsenic levels in wipe samples collected from play structures constructed with CCA-treated wood: Impact on exposure estimates

Energy Technology Data Exchange (ETDEWEB)

Barraj, Leila M. [Chemical Regulation and Food Safety, Exponent, Inc., Suite 1100, 1150 Connecticut Ave., NW, Washington, DC 20036 (United States)], E-mail: lbarraj@exponent.com; Scrafford, Carolyn G. [Chemical Regulation and Food Safety, Exponent, Inc., Suite 1100, 1150 Connecticut Ave., NW, Washington, DC 20036 (United States); Eaton, W. Cary [RTI International, 3040 Cornwallis Road, Research Triangle Park, NC 27709 (United States); Rogers, Robert E.; Jeng, Chwen-Jyh [Toxcon Health Sciences Research Centre Inc., 9607 - 41 Avenue, Edmonton, Alberta, T6E 5X7 (Canada)

2009-04-01

Lumber treated with chromated copper arsenate (CCA) has been used in residential outdoor wood structures and playgrounds. The U.S. EPA has conducted a probabilistic assessment of children's exposure to arsenic from CCA-treated structures using the Stochastic Human Exposure and Dose Simulation model for the wood preservative scenario (SHEDS-Wood). The EPA assessment relied on data from an experimental study using adult volunteers and designed to measure arsenic in maximum hand and wipe loadings. Analyses using arsenic handloading data from a study of children playing on CCA-treated play structures in Edmonton, Canada, indicate that the maximum handloading values significantly overestimate the exposure that occurs during actual play. The objective of our paper is to assess whether the dislodgeable arsenic residues from structures in the Edmonton study are comparable to those observed in other studies and whether they support the conclusion that the values derived by EPA using modeled maximum loading values overestimate hand exposures. We compared dislodgeable arsenic residue data from structures in the playgrounds in the Edmonton study to levels observed in studies used in EPA's assessment. Our analysis showed that the dislodgeable arsenic levels in the Edmonton playground structures are similar to those in the studies used by EPA. Hence, the exposure estimates derived using the handloading data from children playing on CCA-treated structures are more representative of children's actual exposures than the overestimates derived by EPA using modeled maximum values. Handloading data from children playing on CCA-treated structures should be used to reduce the uncertainty of modeled estimates derived using the SHEDS-Wood model.

Sampling inspection device

International Nuclear Information System (INIS)

Chiba, Keiichi.

1996-01-01

A holder is inserted to a holder guide, and is stopped at a position where one end of a hook disposed to the holder is not in contact with the holder guide (a position where hooks do not work). A cap incorporated with wiping paper is pushed up into a holder by a device rod with the wiping paper situated downwardly. The hooks of the holder are engaged to the grooves of the cap to secure the cap. The holder is moved to a predetermined place to wipe off the deposited materials on the surface of a vessel which contains radioactive wastes. Then, the holder is inserted to the holder guide, and is stopped at a position where the one end of the holder is raised. The securement of the gap is released, the cap is forced into a recovering cover by a discharging rod. The hooks of the recovering cover are caught by the grooves of the cap to secure the cap. Then, the cap is transported to a radioactivity measuring chamber. (I.N.)

Toward cost-efficient sampling methods

Science.gov (United States)

Luo, Peng; Li, Yongli; Wu, Chong; Zhang, Guijie

2015-09-01

The sampling method has been paid much attention in the field of complex network in general and statistical physics in particular. This paper proposes two new sampling methods based on the idea that a small part of vertices with high node degree could possess the most structure information of a complex network. The two proposed sampling methods are efficient in sampling high degree nodes so that they would be useful even if the sampling rate is low, which means cost-efficient. The first new sampling method is developed on the basis of the widely used stratified random sampling (SRS) method and the second one improves the famous snowball sampling (SBS) method. In order to demonstrate the validity and accuracy of two new sampling methods, we compare them with the existing sampling methods in three commonly used simulation networks that are scale-free network, random network, small-world network, and also in two real networks. The experimental results illustrate that the two proposed sampling methods perform much better than the existing sampling methods in terms of achieving the true network structure characteristics reflected by clustering coefficient, Bonacich centrality and average path length, especially when the sampling rate is low.

Disinfecting the iPad: evaluating effective methods.

Science.gov (United States)

Howell, V; Thoppil, A; Mariyaselvam, M; Jones, R; Young, H; Sharma, S; Blunt, M; Young, P

2014-06-01

Tablet computers are increasingly used in healthcare, but they may carry nosocomial pathogens. There are few data available on how to clean an iPad effectively for use in the clinical setting. We aimed to identify the most effective method of decontaminating the Apple iPad, without causing damage, and establish the duration of any residual effect. Following contamination with a microbial broth (meticillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant enterococcus (VRE) and Clostridium difficile), we examined efficacy of iPad disinfection in the laboratory using six different disinfectant wipes: Sani-Cloth CHG 2% (chlorhexidine 2%/alcohol 70%), Clorox, Tristel, Trigene, soap and water, and plain cloth. Following cleaning, iPads were recontaminated to examine residual activity. After 480 Sani-Cloth CHG 2% disinfecting episodes, functional and visual analysis of iPads was performed by blinded subjects. With the exception of Clostridium difficile, Sani-Cloth CHG 2% and Clorox wipes were most effective against MRSA and VRE, and they were significantly better than the Apple-recommended plain cloth (P ≤ 0.001). A substantial residual antimicrobial effect was seen for >6h after wiping the iPad with Sani-Cloth CHG 2% despite repeated recontamination and without further disinfection. The functionality or visual appearance of the iPad was not damaged by repeated use of Sani-Cloth CHG 2% wipes. Sani-Cloth CHG 2% wipes effectively disinfect the iPad against MRSA and VRE, with a residual antibacterial effect and without causing damage. Copyright © 2014 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.

Experimental estimation of migration and transfer of organic substances from consumer articles to cotton wipes: Evaluation of underlying mechanisms.

Science.gov (United States)

Clausen, Per Axel; Spaan, Suzanne; Brouwer, Derk H; Marquart, Hans; le Feber, Maaike; Engel, Roel; Geerts, Lieve; Jensen, Keld Alstrup; Kofoed-Sørensen, Vivi; Hansen, Brian; De Brouwere, Katleen

2016-01-01

The aim of this work was to identify the key mechanisms governing transport of organic chemical substances from consumer articles to cotton wipes. The results were used to establish a mechanistic model to improve assessment of dermal contact exposure. Four types of PVC flooring, 10 types of textiles and one type of inkjet printed paper were used to establish the mechanisms and model. Kinetic extraction studies in methanol demonstrated existence of matrix diffusion and indicated the presence of a substance surface layer on some articles. Consequently, the proposed substance transfer model considers mechanical transport from a surface film and matrix diffusion in an article with a known initial total substance concentration. The estimated chemical substance transfer values to cotton wipes were comparable to the literature data (relative transfer ∼ 2%), whereas relative transfer efficiencies from spiked substrates were high (∼ 50%). For consumer articles, high correlation (r(2)=0.92) was observed between predicted and measured transfer efficiencies, but concentrations were overpredicted by a factor of 10. Adjusting the relative transfer from about 50% used in the model to about 2.5% removed overprediction. Further studies are required to confirm the model for generic use.

Towards Cost-efficient Sampling Methods

OpenAIRE

Peng, Luo; Yongli, Li; Chong, Wu

2014-01-01

The sampling method has been paid much attention in the field of complex network in general and statistical physics in particular. This paper presents two new sampling methods based on the perspective that a small part of vertices with high node degree can possess the most structure information of a network. The two proposed sampling methods are efficient in sampling the nodes with high degree. The first new sampling method is improved on the basis of the stratified random sampling method and...

Sampling methods

International Nuclear Information System (INIS)

Loughran, R.J.; Wallbrink, P.J.; Walling, D.E.; Appleby, P.G.

2002-01-01

Methods for the collection of soil samples to determine levels of 137 Cs and other fallout radionuclides, such as excess 210 Pb and 7 Be, will depend on the purposes (aims) of the project, site and soil characteristics, analytical capacity, the total number of samples that can be analysed and the sample mass required. The latter two will depend partly on detector type and capabilities. A variety of field methods have been developed for different field conditions and circumstances over the past twenty years, many of them inherited or adapted from soil science and sedimentology. The use of them inherited or adapted from soil science and sedimentology. The use of 137 Cs in erosion studies has been widely developed, while the application of fallout 210 Pb and 7 Be is still developing. Although it is possible to measure these nuclides simultaneously, it is common for experiments to designed around the use of 137 Cs along. Caesium studies typically involve comparison of the inventories found at eroded or sedimentation sites with that of a 'reference' site. An accurate characterization of the depth distribution of these fallout nuclides is often required in order to apply and/or calibrate the conversion models. However, depending on the tracer involved, the depth distribution, and thus the sampling resolution required to define it, differs. For example, a depth resolution of 1 cm is often adequate when using 137 Cs. However, fallout 210 Pb and 7 Be commonly has very strong surface maxima that decrease exponentially with depth, and fine depth increments are required at or close to the soil surface. Consequently, different depth incremental sampling methods are required when using different fallout radionuclides. Geomorphic investigations also frequently require determination of the depth-distribution of fallout nuclides on slopes and depositional sites as well as their total inventories

Automatic segmentation of Leishmania parasite in microscopic images using a modified CV level set method

Science.gov (United States)

Farahi, Maria; Rabbani, Hossein; Talebi, Ardeshir; Sarrafzadeh, Omid; Ensafi, Shahab

2015-12-01

Visceral Leishmaniasis is a parasitic disease that affects liver, spleen and bone marrow. According to World Health Organization report, definitive diagnosis is possible just by direct observation of the Leishman body in the microscopic image taken from bone marrow samples. We utilize morphological and CV level set method to segment Leishman bodies in digital color microscopic images captured from bone marrow samples. Linear contrast stretching method is used for image enhancement and morphological method is applied to determine the parasite regions and wipe up unwanted objects. Modified global and local CV level set methods are proposed for segmentation and a shape based stopping factor is used to hasten the algorithm. Manual segmentation is considered as ground truth to evaluate the proposed method. This method is tested on 28 samples and achieved 10.90% mean of segmentation error for global model and 9.76% for local model.

Comparisons of methods for generating conditional Poisson samples and Sampford samples

OpenAIRE

Grafström, Anton

2005-01-01

Methods for conditional Poisson sampling (CP-sampling) and Sampford sampling are compared and the focus is on the efficiency of the methods. The efficiency is investigated by simulation in different sampling situations. It was of interest to compare methods since new methods for both CP-sampling and Sampford sampling were introduced by Bondesson, Traat & Lundqvist in 2004. The new methods are acceptance rejection methods that use the efficient Pareto sampling method. They are found to be ...

Organophosphate flame retardants and plasticizers in indoor dust, air and window wipes in newly built low-energy preschools.

Science.gov (United States)

Persson, Josefin; Wang, Thanh; Hagberg, Jessika

2018-07-01

The construction of extremely airtight and energy efficient low-energy buildings is achieved by using functional building materials, such as age-resistant plastics, insulation, adhesives, and sealants. Additives such as organophosphate flame retardants (OPFRs) can be added to some of these building materials as flame retardants and plasticizers. Some OPFRs are considered persistent, bioaccumulative and toxic. Therefore, in this pilot study, the occurrence and distribution of nine OPFRs were determined for dust, air, and window wipe samples collected in newly built low-energy preschools with and without environmental certifications. Tris(1,3-dichloroisopropyl) phosphate (TDCIPP) and triphenyl phosphate (TPHP) were detected in all indoor dust samples at concentrations ranging from 0.014 to 10μg/g and 0.0069 to 79μg/g, respectively. Only six OPFRs (predominantly chlorinated OPFRs) were detected in the indoor air. All nine OPFRs were found on the window surfaces and the highest concentrations, which occurred in the reference preschool, were measured for 2-ethylhexyl diphenyl phosphate (EHDPP) (maximum concentration: 1500ng/m 2 ). Interestingly, the OPFR levels in the environmental certified low-energy preschools were lower than those in the reference preschool and the non-certified low-energy preschool, probably attributed to the usage of environmental friendly and low-emitting building materials, interior decorations, and consumer products. Copyright © 2018 Elsevier B.V. All rights reserved.

Phase 1 sampling and analysis plan for the 304 Concretion Facility closure activities

International Nuclear Information System (INIS)

Adler, J.G.

1994-01-01

This document provides guidance for the initial (Phase 1) sampling and analysis activities associated with the proposed Resource Conservation and Recovery Act of 1976 (RCRA) clean closure of the 304 Concretion Facility. Over its service life, the 304 Concretion Facility housed the pilot plants associated with cladding uranium cores, was used to store engineering equipment and product chemicals, was used to treat low-level radioactive mixed waste, recyclable scrap uranium generated during nuclear fuel fabrication, and uranium-titanium alloy chips, and was used for the repackaging of spent halogenated solvents from the nuclear fuels manufacturing process. The strategy for clean closure of the 304 Concretion Facility is to decontaminate, sample (Phase 1 sampling), and evaluate results. If the evaluation indicates that a limited area requires additional decontamination for clean closure, the limited area will be decontaminated, resampled (Phase 2 sampling), and the result evaluated. If the evaluation indicates that the constituents of concern are below action levels, the facility will be clean closed. Or, if the evaluation indicates that the constituents of concern are present above action levels, the condition of the facility will be evaluated and appropriate action taken. There are a total of 37 sampling locations comprising 12 concrete core, 1 concrete chip, 9 soil, 11 wipe, and 4 asphalt core sampling locations. Analysis for inorganics and volatile organics will be performed on the concrete core and soil samples. Separate concrete core samples will be required for the inorganic and volatile organic analysis (VOA). Analysis for inorganics only will be performed on the concrete chip, wipe, and asphalt samples

Laboratory Studies on Surface Sampling of Bacillus anthracis Contamination: Summary, Gaps, and Recommendations

Energy Technology Data Exchange (ETDEWEB)

Piepel, Gregory F.; Amidan, Brett G.; Hu, Rebecca

2011-11-28

This report summarizes previous laboratory studies to characterize the performance of methods for collecting, storing/transporting, processing, and analyzing samples from surfaces contaminated by Bacillus anthracis or related surrogates. The focus is on plate culture and count estimates of surface contamination for swab, wipe, and vacuum samples of porous and nonporous surfaces. Summaries of the previous studies and their results were assessed to identify gaps in information needed as inputs to calculate key parameters critical to risk management in biothreat incidents. One key parameter is the number of samples needed to make characterization or clearance decisions with specified statistical confidence. Other key parameters include the ability to calculate, following contamination incidents, the (1) estimates of Bacillus anthracis contamination, as well as the bias and uncertainties in the estimates, and (2) confidence in characterization and clearance decisions for contaminated or decontaminated buildings. Gaps in knowledge and understanding identified during the summary of the studies are discussed and recommendations are given for future studies.

Sampling by sponge wipe or skin excision for recovery of inoculated Salmonella and Campylobacter from defeathered broiler carcasses

Science.gov (United States)

Broilers may carry Salmonella and Campylobacter on inner and outer surfaces upon arrival at the slaughter plant and carcasses can be further contaminated during commercial processing. A sensitive, non-destructive, repeatable sampling method would be useful to test carcasses for levels of bacteria b...

Concentration of a sodium nitrate-based waste with a wiped film evaporation

International Nuclear Information System (INIS)

Farr, L.L.; Boring, M.D.; Fowler, V.L.; Hewitt, J.D.

1995-01-01

Oak Ridge National Laboratory (ORNL) currently has an inventory of 500,000 gallons of sodium nitrate-based radioactive liquid waste which is currently stored in the Melton Valley Storage Tanks (MVST). This waste needs to be treated and one option being considered is concentration of the wastes using evaporation. Testing is underway to determine whether a Wiped Film Evaporator (WFE) can be used to concentrate these wastes in an economical and reliable manner. The capability of the evaporator to process a non-radioactive simulant of the MVST wastes over a range of operating conditions is being studied. The equipment has to be checked for reliability, potential corrosion problems, and the effects of the waste on the efficiency of heat transfer due to scaling. Physical and chemical characteristics of the product and distillate are being investigated. Heat transfer coefficients and volume reductions are being determined under different operating conditions. Decontamination factors are being calculated to determine the necessity for further treatment of the distillate and off-gas

Dermal transfer quantification of nanoparticles from nano-enabled surfaces

DEFF Research Database (Denmark)

Mackevica, Aiga; Olsson, Mikael Emil; Mines, Paul D.

2018-01-01

). The dermal transfer testing by wipe sampling and analytical approach used in this study demonstrates that wipe testing in combination with spICP-MS analysis can provide both qualitative data in terms of mass and number-based NP release, as well as particle characterization in terms of NP size distribution...... and characterize NP release from keyboard covers and freshly painted surfaces, in terms of mass and number concentration, as well as released particle size distribution through the use of spICP-MS. Three types of NPs were selected for method validation testing, Ag, TiO2, and CuO; and, the particle extraction from...... wipes was found to be efficient for Ag and CuO, but not for TiO2 particles. Thereafter, potential dermal transfer was tested by wipe sampling for two nanoAg-containing silicon keyboard covers, and wood painted with nanoCuO-containing paint. AgNP release was observed for one of the keyboard cover types...

Distance sampling methods and applications

CERN Document Server

Buckland, S T; Marques, T A; Oedekoven, C S

2015-01-01

In this book, the authors cover the basic methods and advances within distance sampling that are most valuable to practitioners and in ecology more broadly. This is the fourth book dedicated to distance sampling. In the decade since the last book published, there have been a number of new developments. The intervening years have also shown which advances are of most use. This self-contained book covers topics from the previous publications, while also including recent developments in method, software and application. Distance sampling refers to a suite of methods, including line and point transect sampling, in which animal density or abundance is estimated from a sample of distances to detected individuals. The book illustrates these methods through case studies; data sets and computer code are supplied to readers through the book’s accompanying website.  Some of the case studies use the software Distance, while others use R code. The book is in three parts.  The first part addresses basic methods, the ...

Sampling the stratum corneum for toxic chemicals.

Science.gov (United States)

Coman, Garrett; Blickenstaff, Nicholas R; Blattner, Collin M; Andersen, Rosa; Maibach, Howard I

2014-01-01

Dermal exposure is an important pathway in environmental health. Exposure comes from contaminated water, soil, treated surfaces, textiles, aerosolized chemicals, and agricultural products. It can occur in homes, schools, play areas, and work settings in the form of industrial sources, consumer products, or hazardous wastes. Dermal exposure is most likely to occur through contact with liquids, water, soil, sediment, and contaminated surfaces. The ability to detect and measure exposure to toxic materials on the skin is an important environmental health issue. The stratum corneum is the skin's first and principal barrier layer of protection from the outside world. It has a complex structure that can effectively protect against a wide variety of physical, chemical, and biological contaminants. However, there are a variety of chemical agents that can damage the stratum corneum and the underlying epidermis, dermis and subcutis, and/or enter systemic circulation through the skin. There are numerous ways of sampling the stratum corneum for these toxic materials like abrasion techniques, biopsy, suction blistering, imaging, washing, wipe sampling, tape stripping, and spot testing. Selecting a method likely depends on the particular needs of the situation. Hence, there is a need to review practical considerations for their use in sampling the stratum corneum for toxins.

A novel challenge test incorporating irradiation (60Co) of compost sub-samples to validate thermal lethality towards pathogenic bacteria.

Science.gov (United States)

Moore, John E; Watabe, Miyuki; Stewart, Andrew; Cherie Millar, B; Rao, Juluri R

2009-01-01

Maturing compost heaps normally attaining temperatures ranging from 55 to 65 degrees C is generally regarded to conform to recommended biological risks and sanitation standards for composts stipulated by either EU or US-EPA. Composted products derived from animal sources are further required by EU biohazard safety regulatory legislation that such composts either attain 70 degrees C for over 3h during maturation or via treatment at 70 degrees C for 1h before being considered for dispensation on land. The setting of the upper limit of thermal lethality at 70 degrees C/1h for achieving biosecurity of the animal waste composted products (e.g. pelleted fertilizer formulations) is not properly substantiated by specific validation tests, comprising a 'wipe-out' step (usually via autoclaving) followed by inoculation of a prescribed bacterium, exposure to 70 degrees C/1h and the lethality determined. Pelleted formulations of composts are not amenable for wet methods (autoclaving) for wipe-out sterilization step as this is detrimental to the pellet and compromises sample integrity. This study describes a laboratory method involving the employment of ((60)Co) irradiation 'wipe-out' step to: (a) compost sub-samples drawn from compost formulation heaps and (b) pelleted products derived from composted animal products while determining the thermal lethality of a given time/temperature (70 degrees C/1h) treatment process and by challenging the irradiated sample (not just with one bacterium but), out with 10 potential food-poisoning organisms from the bacterial genera (Campylobacter, Escherichia, Listeria, Salmonella, Yersinia) frequently detected in pig and poultry farm wastes. This challenge test on compost sub-samples can be a useful intervention ploy for 'inspection and validation' technique for composters during the compost maturity process, whose attainment of temperatures of 55-65 degrees C is presumed sufficient for attainment of sanitation. Stringent measures are further

Workflow for the Targeted and Untargeted Detection of Small Metabolites in Fish Skin Mucus

Directory of Open Access Journals (Sweden)

Lada Ivanova

2018-06-01

Full Text Available The skin mucus of fish is in permanent contact with the aquatic environment. Data from the analysis of the chemical composition of skin mucus could potentially be used for monitoring the health status of the fish. Knowledge about mucus composition or change in composition over time could also contribute to understanding the aetiology of certain diseases. The objective of the present study was the development of a workflow for non-invasive sampling of skin mucus from farmed salmon (Salmo salar for the targeted and untargeted detection of small metabolites. Skin mucus was either scraped off, wiped off using medical wipes, or the mucus’ water phase was absorbed using the same type of medical wipes that was used for the wiping method. Following a simple filtration step, the obtained mucus samples were subjected to hydrophilic interaction chromatography coupled to high-resolution mass spectrometry. Post-acquisition processing included the targeted analysis of 86 small metabolites, of which up to 60 were detected in absorbed mucus. Untargeted analysis of the mucus samples from equally treated salmon revealed that the total variation of the metabolome was lowest in absorbed mucus and highest in the scraped mucus. Thus, future studies including small-molecule metabolomics of skin mucus in fish would benefit from a sampling regime employing absorption of the water phase in order to minimize the bias related to the sampling step. Furthermore, the absorption method is also a less invasive approach allowing for repetitive sampling within short time intervals.

Independent random sampling methods

CERN Document Server

Martino, Luca; Míguez, Joaquín

2018-01-01

This book systematically addresses the design and analysis of efficient techniques for independent random sampling. Both general-purpose approaches, which can be used to generate samples from arbitrary probability distributions, and tailored techniques, designed to efficiently address common real-world practical problems, are introduced and discussed in detail. In turn, the monograph presents fundamental results and methodologies in the field, elaborating and developing them into the latest techniques. The theory and methods are illustrated with a varied collection of examples, which are discussed in detail in the text and supplemented with ready-to-run computer code. The main problem addressed in the book is how to generate independent random samples from an arbitrary probability distribution with the weakest possible constraints or assumptions in a form suitable for practical implementation. The authors review the fundamental results and methods in the field, address the latest methods, and emphasize the li...

A method of language sampling

DEFF Research Database (Denmark)

Rijkhoff, Jan; Bakker, Dik; Hengeveld, Kees

1993-01-01

In recent years more attention is paid to the quality of language samples in typological work. Without an adequate sampling strategy, samples may suffer from various kinds of bias. In this article we propose a sampling method in which the genetic criterion is taken as the most important: samples...... created with this method will reflect optimally the diversity of the languages of the world. On the basis of the internal structure of each genetic language tree a measure is computed that reflects the linguistic diversity in the language families represented by these trees. This measure is used...... to determine how many languages from each phylum should be selected, given any required sample size....

Low pH levels wipe out salmon and trout populations in southernmost Norway

Energy Technology Data Exchange (ETDEWEB)

Jensen, K W; Snekvik, E

1972-01-01

A gradual decrease in pH has been documented for many Scandinavian rivers and lakes and there is little doubt that the main cause is acid precipitation (1-4). Eggs, fry, and alevins of salmon and brown trout are more susceptible to acid water than are the older fish. A gradually increasing acidity of trout biotopes will cause a reduction in the natural reproduction rate of trout, because eggs and fry succumb, while the older individuals in the population survive, at least until the pH level sinks low enough to affect them, as well. A study of the present situation and examination of the available data show that the salmon populations in a number of rivers in southernmost Norway have been nearly wiped out by low pH values. During the last twenty to thirty years, low pH levels have eliminated the brown trout populations in a great number of lakes and rivers in Norway's southernmost districts. This alarming development is continuing.

SWOT ANALYSIS ON SAMPLING METHOD

Directory of Open Access Journals (Sweden)

CHIS ANCA OANA

2014-07-01

Full Text Available Audit sampling involves the application of audit procedures to less than 100% of items within an account balance or class of transactions. Our article aims to study audit sampling in audit of financial statements. As an audit technique largely used, in both its statistical and nonstatistical form, the method is very important for auditors. It should be applied correctly for a fair view of financial statements, to satisfy the needs of all financial users. In order to be applied correctly the method must be understood by all its users and mainly by auditors. Otherwise the risk of not applying it correctly would cause loose of reputation and discredit, litigations and even prison. Since there is not a unitary practice and methodology for applying the technique, the risk of incorrectly applying it is pretty high. The SWOT analysis is a technique used that shows the advantages, disadvantages, threats and opportunities. We applied SWOT analysis in studying the sampling method, from the perspective of three players: the audit company, the audited entity and users of financial statements. The study shows that by applying the sampling method the audit company and the audited entity both save time, effort and money. The disadvantages of the method are difficulty in applying and understanding its insight. Being largely used as an audit method and being a factor of a correct audit opinion, the sampling method’s advantages, disadvantages, threats and opportunities must be understood by auditors.

Sampling system and method

Science.gov (United States)

Decker, David L.; Lyles, Brad F.; Purcell, Richard G.; Hershey, Ronald Lee

2013-04-16

The present disclosure provides an apparatus and method for coupling conduit segments together. A first pump obtains a sample and transmits it through a first conduit to a reservoir accessible by a second pump. The second pump further conducts the sample from the reservoir through a second conduit.

A method of language sampling

DEFF Research Database (Denmark)

Rijkhoff, Jan; Bakker, Dik; Hengeveld, Kees

1993-01-01

In recent years more attention is paid to the quality of language samples in typological work. Without an adequate sampling strategy, samples may suffer from various kinds of bias. In this article we propose a sampling method in which the genetic criterion is taken as the most important: samples...... to determine how many languages from each phylum should be selected, given any required sample size....

Reducing health care-associated infections by implementing separated environmental cleaning management measures by using disposable wipes of four colors.

Science.gov (United States)

Wong, Swee Siang; Huang, Cheng Hua; Yang, Chiu Chu; Hsieh, Yi Pei; Kuo, Chen Ni; Chen, Yi Ru; Chen, Li Ching

2018-01-01

Environmental cleaning is a fundamental principle of infection control in health care settings. We determined whether implementing separated environmental cleaning management measures in MICU reduced the density of HAI. We performed a 4-month prospective cohort intervention study between August and December 2013, at the MICU of Cathay General hospital. We arranged a training program for all the cleaning staff regarding separated environmental cleaning management measures by using disposable wipes of four colors to clean the patients' bedside areas, areas at a high risk of contamination, paperwork areas, and public areas. Fifteen high-touch surfaces were selected for cleanliness evaluation by using the adenosine triphosphate (ATP) bioluminescence test. Then data regarding HAI densities in the MICU were collected during the baseline, intervention, and late periods. A total of 120 ATP readings were obtained. The total number of clean high-touch surfaces increased from 13% to 53%, whereas that of unclean high-touch surface decreased from 47% to 20%. The densities of HAI were 14.32‰ and 14.90‰ during the baseline and intervention periods, respectively. The HAI density did not decrease after the intervention period, but it decreased to 9.07‰ during the late period. Implementing separated environmental cleaning management measures by using disposable wipes of four colors effectively improves cleanliness in MICU environments. However, no decrease in HAI density was observed within the study period. Considering that achieving high levels of hand-hygiene adherence is difficult, improving environmental cleaning is a crucial adjunctive measure for reducing the incidence of HAIs.

Subrandom methods for multidimensional nonuniform sampling.

Science.gov (United States)

Worley, Bradley

2016-08-01

Methods of nonuniform sampling that utilize pseudorandom number sequences to select points from a weighted Nyquist grid are commonplace in biomolecular NMR studies, due to the beneficial incoherence introduced by pseudorandom sampling. However, these methods require the specification of a non-arbitrary seed number in order to initialize a pseudorandom number generator. Because the performance of pseudorandom sampling schedules can substantially vary based on seed number, this can complicate the task of routine data collection. Approaches such as jittered sampling and stochastic gap sampling are effective at reducing random seed dependence of nonuniform sampling schedules, but still require the specification of a seed number. This work formalizes the use of subrandom number sequences in nonuniform sampling as a means of seed-independent sampling, and compares the performance of three subrandom methods to their pseudorandom counterparts using commonly applied schedule performance metrics. Reconstruction results using experimental datasets are also provided to validate claims made using these performance metrics. Copyright © 2016 Elsevier Inc. All rights reserved.

Some connections between importance sampling and enhanced sampling methods in molecular dynamics.

Science.gov (United States)

Lie, H C; Quer, J

2017-11-21

In molecular dynamics, enhanced sampling methods enable the collection of better statistics of rare events from a reference or target distribution. We show that a large class of these methods is based on the idea of importance sampling from mathematical statistics. We illustrate this connection by comparing the Hartmann-Schütte method for rare event simulation (J. Stat. Mech. Theor. Exp. 2012, P11004) and the Valsson-Parrinello method of variationally enhanced sampling [Phys. Rev. Lett. 113, 090601 (2014)]. We use this connection in order to discuss how recent results from the Monte Carlo methods literature can guide the development of enhanced sampling methods.

Perpendicular distance sampling: an alternative method for sampling downed coarse woody debris

Science.gov (United States)

Michael S. Williams; Jeffrey H. Gove

2003-01-01

Coarse woody debris (CWD) plays an important role in many forest ecosystem processes. In recent years, a number of new methods have been proposed to sample CWD. These methods select individual logs into the sample using some form of unequal probability sampling. One concern with most of these methods is the difficulty in estimating the volume of each log. A new method...

Sampling method of environmental radioactivity monitoring

International Nuclear Information System (INIS)

1984-01-01

This manual provides sampling methods of environmental samples of airborne dust, precipitated dust, precipitated water (rain or snow), fresh water, soil, river sediment or lake sediment, discharged water from a nuclear facility, grains, tea, milk, pasture grass, limnetic organisms, daily diet, index organisms, sea water, marine sediment, marine organisms, and that for tritium and radioiodine determination for radiation monitoring from radioactive fallout or radioactivity release by nuclear facilities. This manual aims at the presentation of standard sampling procedures for environmental radioactivity monitoring regardless of monitoring objectives, and shows preservation method of environmental samples acquired at the samplingpoint for radiation counting for those except human body. Sampling techniques adopted in this manual is decided by the criteria that they are suitable for routine monitoring and any special skillfulness is not necessary. Based on the above-mentioned principle, this manual presents outline and aims of sampling, sampling position or object, sampling quantity, apparatus, equipment or vessel for sampling, sampling location, sampling procedures, pretreatment and preparation procedures of a sample for radiation counting, necessary recording items for sampling and sample transportation procedures. Special attention is described in the chapter of tritium and radioiodine because these radionuclides might be lost by the above-mentioned sample preservation method for radiation counting of less volatile radionuclides than tritium or radioiodine. (Takagi, S.)

A pilot study of the efficacy of wipes containing chlorhexidine 0.3%, climbazole 0.5% and Tris-EDTA to reduce Malassezia pachydermatis populations on canine skin

Science.gov (United States)

Cavana, Paola; Peano, Andrea; Petit, Jean-Yanique; Tizzani, Paolo; Perrot, Sébastien; Bensignor, Emmanuel; Guillot, Jacques

2015-01-01

Background Wipes containing chlorhexidine and azole derivates have been recommended for veterinary use. No study has been published about their activity against Malassezia pachydermatis. Hypothesis/Objectives To evaluate the in vivo and in vitro activity of wipes soaked in a chlorhexidine, climbazole and Tris-EDTA solution against Malassezia pachydermatis. Animals Five research colony shar-pei dogs. Methods Wipes were applied once daily onto the left axilla, left groin and perianal area (protocol A), and twice daily on the right axilla, right groin and umbilical region (protocol B) for 3 days. In vivo activity was evaluated by quantifying Malassezia colonies through contact plates on the selected body areas before and after wipe application. The activity of the solution in which the wipes were soaked was assessed in vitro by contact tests following the European Standard UNI EN 1275 guidelines. Results Samples collected after wipe application showed a significant and rapid reduction of Malassezia yeast CFU. No significant difference in the Malassezia reduction was found between protocols A and B. In vitro assay showed 100% activity against Malassezia yeasts after a 15 min contact time with the wipe solution. Conclusions and clinical importance Wipes containing chlorhexidine, climbazole and Tris-EDTA substantially reduced the M. pachydermatis population on the skin of dogs. The results, although this was an uncontrolled study performed on a small number of dogs, suggest that these wipes may be useful for topical therapy of Malassezia dermatitis involving the lips, paws, perianal area and skin folds. Résumé Contexte Des lingettes contenant de la chlorhexidine et des dérivésazolés ont été recommandés en médicine vétérinaire. Aucune étude n'a été publiée sur leur activité contre Malassezia pachydermatis. Hypothèses/Objectifs Evaluer l'activité in vivo et in vitro de lingettes imprégnées d'une solution de chlorhexidine, climbazole et Tris

Open Loop Heat Pipe Radiator Having a Free-Piston for Wiping Condensed Working Fluid

Science.gov (United States)

Weinstein, Leonard M. (Inventor)

2015-01-01

An open loop heat pipe radiator comprises a radiator tube and a free-piston. The radiator tube has a first end, a second end, and a tube wall, and the tube wall has an inner surface and an outer surface. The free-piston is enclosed within the radiator tube and is capable of movement within the radiator tube between the first and second ends. The free-piston defines a first space between the free-piston, the first end, and the tube wall, and further defines a second space between the free-piston, the second end, and the tube wall. A gaseous-state working fluid, which was evaporated to remove waste heat, alternately enters the first and second spaces, and the free-piston wipes condensed working fluid from the inner surface of the tube wall as the free-piston alternately moves between the first and second ends. The condensed working fluid is then pumped back to the heat source.

EVALUATING COMMERCIALLY AVAILABLE DERMAL ...

Science.gov (United States)

As the Human Exposure Program focuses on the exposure of children to pesticides, there are concerns about the effect, or perceived effect, of components of the sampling procedure on the health and well-being of the infant and the ability to collect pesticide residues. One concern involves the materials in wipes used to collect pesticide residues or other contact materials on the skin. In recent studies (e.g., National Human Exposure Assessment Survey; NHEXAS), isopropyl alcohol has been used as a solvent in conjunction with a cloth wipe to obtain samples from the hands of adults and children. Although isopropyl alcohol is generally considered innocuous, the use of commercially available products could eliminate concerns about exposure to alcohol. A few studies have evaluated the potential of commercially available baby wipes to collect personal exposure samples for metals research, but not for the area of pesticide research (Millson et al., 1994; Campbell et al., 1993; Lichtenwalner et al., 1993). Therefore, there is a need to evaluate the potential for using commercially available baby wipes for collecting pesticide samples from skin and other surfaces. Another concern involves establishing a convenient and safe method for assessing overall dermal exposure for children, especially for those in crawling stage. One route that the U .S. Environmental Protection Agency (EPA) would like to investigate is the use of cotton body suits (infant sleepers) as an indicator

An improved sampling method of complex network

Science.gov (United States)

Gao, Qi; Ding, Xintong; Pan, Feng; Li, Weixing

2014-12-01

Sampling subnet is an important topic of complex network research. Sampling methods influence the structure and characteristics of subnet. Random multiple snowball with Cohen (RMSC) process sampling which combines the advantages of random sampling and snowball sampling is proposed in this paper. It has the ability to explore global information and discover the local structure at the same time. The experiments indicate that this novel sampling method could keep the similarity between sampling subnet and original network on degree distribution, connectivity rate and average shortest path. This method is applicable to the situation where the prior knowledge about degree distribution of original network is not sufficient.

Comparison of sampling methods for animal manure

NARCIS (Netherlands)

Derikx, P.J.L.; Ogink, N.W.M.; Hoeksma, P.

1997-01-01

Currently available and recently developed sampling methods for slurry and solid manure were tested for bias and reproducibility in the determination of total phosphorus and nitrogen content of samples. Sampling methods were based on techniques in which samples were taken either during loading from

Occupational exposures to styrene vapor in a manufacturing plant for fiber-reinforced composite wind turbine blades.

Science.gov (United States)

Hammond, Duane; Garcia, Alberto; Feng, H Amy

2011-07-01

A utility-scale wind turbine blade manufacturing plant requested assistance from the National Institute for Occupational Safety and Health (NIOSH) in controlling worker exposures to styrene at a plant that produced 37 and 42 m long fiber-reinforced wind turbine blades. The plant requested NIOSH assistance because previous air sampling conducted by the company indicated concerns about peak styrene concentrations when workers entered the confined space inside of the wind turbine blade. NIOSH researchers conducted two site visits and collected personal breathing zone and area air samples while workers performed the wind turbine blade manufacturing tasks of vacuum-assisted resin transfer molding (VARTM), gelcoating, glue wiping, and installing the safety platform. All samples were collected during the course of normal employee work activities and analyzed for styrene using NIOSH Method 1501. All sampling was task based since full-shift sampling from a prior Occupational Safety and Health Administration (OSHA) compliance inspection did not show any exposures to styrene above the OSHA permissible exposure limit. During the initial NIOSH site visit, 67 personal breathing zone and 18 area air samples were collected while workers performed tasks of VARTM, gelcoating, glue wipe, and installation of a safety platform. After the initial site visit, the company made changes to the glue wipe task that eliminated the need for workers to enter the confined space inside of the wind turbine blade. During the follow-up site visit, 12 personal breathing zone and 8 area air samples were collected from workers performing the modified glue wipe task. During the initial site visit, the geometric means of the personal breathing zone styrene air samples were 1.8 p.p.m. (n = 21) for workers performing the VARTM task, 68 p.p.m. (n = 5) for workers installing a safety platform, and 340 p.p.m. (n = 14) for workers performing the glue wipe task, where n is the number of workers sampled for a

7 CFR 29.110 - Method of sampling.

Science.gov (United States)

2010-01-01

... 7 Agriculture 2 2010-01-01 2010-01-01 false Method of sampling. 29.110 Section 29.110 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... INSPECTION Regulations Inspectors, Samplers, and Weighers § 29.110 Method of sampling. In sampling tobacco...

Uniform Sampling Table Method and its Applications II--Evaluating the Uniform Sampling by Experiment.

Science.gov (United States)

Chen, Yibin; Chen, Jiaxi; Chen, Xuan; Wang, Min; Wang, Wei

2015-01-01

A new method of uniform sampling is evaluated in this paper. The items and indexes were adopted to evaluate the rationality of the uniform sampling. The evaluation items included convenience of operation, uniformity of sampling site distribution, and accuracy and precision of measured results. The evaluation indexes included operational complexity, occupation rate of sampling site in a row and column, relative accuracy of pill weight, and relative deviation of pill weight. They were obtained from three kinds of drugs with different shape and size by four kinds of sampling methods. Gray correlation analysis was adopted to make the comprehensive evaluation by comparing it with the standard method. The experimental results showed that the convenience of uniform sampling method was 1 (100%), odds ratio of occupation rate in a row and column was infinity, relative accuracy was 99.50-99.89%, reproducibility RSD was 0.45-0.89%, and weighted incidence degree exceeded the standard method. Hence, the uniform sampling method was easy to operate, and the selected samples were distributed uniformly. The experimental results demonstrated that the uniform sampling method has good accuracy and reproducibility, which can be put into use in drugs analysis.

Aspects of cleaning environmental materials for multi-element analysis, e.g. plant samples

International Nuclear Information System (INIS)

Markert, B.

1992-01-01

Cleaning of samples is often the first step in the entire procedure of sample preparation in environmental trace element research. The question must generally be raised of whether cleaning is meaningful before chemical investigations with plant material (e.g. for the determination of transfer factors in the soil/plant system) or not (e.g. for food chain analysis in the plant/animal system). The most varied cleaning procedures for plant samples are currently available ranging from dry and wet wiping of the leaf or needle surface up to the complete removal of the cuticule with the aid of chlorofom. There is at present no standardized cleaning procedure for plant samples so that it is frequently not possible to compare analytical data from different working groups studying the same plant species. (orig.)

Optical molecular fluorescence determination of ultra-trace beryllium in occupational and environmental samples using highly alkaline conditions.

Science.gov (United States)

Adams, Lori; Agrawal, Anoop; Cronin, John P; Ashley, Kevin

2017-01-01

Exposures to beryllium (Be), even at extremely low levels, can cause severe health effects in a percentage of those exposed; consequently, occupational exposure limits (OELs) promulgated for this element are the lowest established for any element. This work describes the advantages of using highly alkaline dye solutions for determination of Be in occupational hygiene and environmental samples by means of an optical molecular fluorescence technique after sample extraction in 1-3% (w˖w -1 ) aqueous ammonium bifluoride (NH 4 HF 2 ). Improved attributes include the ability to further enhance the detection limits of Be in extraction solutions of high acidity with minimal dilution, which is particularly beneficial when NH 4 HF 2 solutions of higher concentration are used for extraction of Be from soil samples. Significant improvements in Be method detection limits (MDLs) are obtained at levels many-fold below those reported previously for this methodology. Notably, MDLs for Be of health organizations and regulatory agencies in the USA and internationally. Applications of enhanced Be measurements to air filter samples, surface wipe samples, soils and newly-designed occupational air sampler inserts are illustrated.

19 CFR 151.83 - Method of sampling.

Science.gov (United States)

2010-04-01

... 19 Customs Duties 2 2010-04-01 2010-04-01 false Method of sampling. 151.83 Section 151.83 Customs Duties U.S. CUSTOMS AND BORDER PROTECTION, DEPARTMENT OF HOMELAND SECURITY; DEPARTMENT OF THE TREASURY (CONTINUED) EXAMINATION, SAMPLING, AND TESTING OF MERCHANDISE Cotton § 151.83 Method of sampling. For...

ALARA ASSESSMENT OF SETTLER SLUDGE SAMPLING METHODS

International Nuclear Information System (INIS)

Nelsen, L.A.

2009-01-01

The purpose of this assessment is to compare underwater and above water settler sludge sampling methods to determine if the added cost for underwater sampling for the sole purpose of worker dose reductions is justified. Initial planning for sludge sampling included container, settler and knock-out-pot (KOP) sampling. Due to the significantly higher dose consequence of KOP sludge, a decision was made to sample KOP underwater to achieve worker dose reductions. Additionally, initial plans were to utilize the underwater sampling apparatus for settler sludge. Since there are no longer plans to sample KOP sludge, the decision for underwater sampling for settler sludge needs to be revisited. The present sampling plan calls for spending an estimated $2,500,000 to design and construct a new underwater sampling system (per A21 C-PL-001 RevOE). This evaluation will compare and contrast the present method of above water sampling to the underwater method that is planned by the Sludge Treatment Project (STP) and determine if settler samples can be taken using the existing sampling cart (with potentially minor modifications) while maintaining doses to workers As Low As Reasonably Achievable (ALARA) and eliminate the need for costly redesigns, testing and personnel retraining

ALARA ASSESSMENT OF SETTLER SLUDGE SAMPLING METHODS

Energy Technology Data Exchange (ETDEWEB)

NELSEN LA

2009-01-30

The purpose of this assessment is to compare underwater and above water settler sludge sampling methods to determine if the added cost for underwater sampling for the sole purpose of worker dose reductions is justified. Initial planning for sludge sampling included container, settler and knock-out-pot (KOP) sampling. Due to the significantly higher dose consequence of KOP sludge, a decision was made to sample KOP underwater to achieve worker dose reductions. Additionally, initial plans were to utilize the underwater sampling apparatus for settler sludge. Since there are no longer plans to sample KOP sludge, the decision for underwater sampling for settler sludge needs to be revisited. The present sampling plan calls for spending an estimated $2,500,000 to design and construct a new underwater sampling system (per A21 C-PL-001 RevOE). This evaluation will compare and contrast the present method of above water sampling to the underwater method that is planned by the Sludge Treatment Project (STP) and determine if settler samples can be taken using the existing sampling cart (with potentially minor modifications) while maintaining doses to workers As Low As Reasonably Achievable (ALARA) and eliminate the need for costly redesigns, testing and personnel retraining.

Clearance measurements on activated parts of accelerators by combined methods; Verfahrenskombinierte Freigabemessung aktivierter Beschleunigerteile

Energy Technology Data Exchange (ETDEWEB)

Jansen, S.; Friedemann, S. [VKTA, Dresden (Germany); Enghardt, W. [Technische Univ. Dresden (Germany). OncoRay

2016-07-01

The process of clearance of radioactive materials according to paragraph 29 StrlSchV contents the comparison of activity to mass and surface of the material. To avoid a borderless assessment of activity of activation it is often necessary to use combined measurement methods: For clearance of collimators of a medical proton accelerator (energy range up to 200 MeV) it needs to know the nuclide composition. The energetical and geometrical calibration was fixed by experiments. The clearance based on measurements of activity distribution, gammaspectroscopy verification of nuclide composition and gamma-counting detectors. Parts of medical electron-accelerators achieved its clearance by combination of abovementioned methods and in-situ-gammaspectroscopy. Activated und contaminated lead stones achieved its clearance by measurements of fluence, laboratory evaluation of samples, in-situ-gammaspectroscopy and wipe tests.

Standard methods for sampling and sample preparation for gamma spectroscopy

International Nuclear Information System (INIS)

Taskaeva, M.; Taskaev, E.; Nikolov, P.

1993-01-01

The strategy for sampling and sample preparation is outlined: necessary number of samples; analysis and treatment of the results received; quantity of the analysed material according to the radionuclide concentrations and analytical methods; the minimal quantity and kind of the data needed for making final conclusions and decisions on the base of the results received. This strategy was tested in gamma spectroscopic analysis of radionuclide contamination of the region of Eleshnitsa Uranium Mines. The water samples was taken and stored according to the ASTM D 3370-82. The general sampling procedures were in conformity with the recommendations of ISO 5667. The radionuclides was concentrated by coprecipitation with iron hydroxide and ion exchange. The sampling of soil samples complied with the rules of ASTM C 998, and their sample preparation - with ASTM C 999. After preparation the samples were sealed hermetically and measured. (author)

Sampling bee communities using pan traps: alternative methods increase sample size

Science.gov (United States)

Monitoring of the status of bee populations and inventories of bee faunas require systematic sampling. Efficiency and ease of implementation has encouraged the use of pan traps to sample bees. Efforts to find an optimal standardized sampling method for pan traps have focused on pan trap color. Th...

New adaptive sampling method in particle image velocimetry

International Nuclear Information System (INIS)

Yu, Kaikai; Xu, Jinglei; Tang, Lan; Mo, Jianwei

2015-01-01

This study proposes a new adaptive method to enable the number of interrogation windows and their positions in a particle image velocimetry (PIV) image interrogation algorithm to become self-adapted according to the seeding density. The proposed method can relax the constraint of uniform sampling rate and uniform window size commonly adopted in the traditional PIV algorithm. In addition, the positions of the sampling points are redistributed on the basis of the spring force generated by the sampling points. The advantages include control of the number of interrogation windows according to the local seeding density and smoother distribution of sampling points. The reliability of the adaptive sampling method is illustrated by processing synthetic and experimental images. The synthetic example attests to the advantages of the sampling method. Compared with that of the uniform interrogation technique in the experimental application, the spatial resolution is locally enhanced when using the proposed sampling method. (technical design note)

Evaluation of Various Cleaning Methods to Remove Bacillus Spores from Spacecraft Hardware Materials

Science.gov (United States)

Venkateswaran, Kasthuri; Chung, Shirley; Allton, Judith; Kern, Roger

2004-09-01

A detailed study was made of the biological cleaning effectiveness, defined in terms of the ability to remove bacterial spores, of a number of methods used to clean hardware surfaces. Aluminum (Al 6061) and titanium (Ti 6Al-4V) were chosen for the study as they were deemed the two materials most likely to be used in spacecraft extraterrestrial sampler construction. Metal coupons (1 cm × 2.5 cm) were precleaned and inoculated with 5.8 × 103 cultivable Bacillus subtilis spores, which are commonly found on spacecraft surfaces and in the assembly environments. The inoculated coupons were subsequently cleaned using: (1) 70% isopropyl alcohol wipe; (2) water wipe; (3) multiple-solvent flight-hardware cleaning procedures used at the Jet Propulsion Laboratory (JPL); (4) Johnson Space Center-developed ultrapure water rinse; and (5) a commercial, semi-aqueous, multiple-solvent (SAMS) cleaning process. The biological cleaning effectiveness was measured by agar plate assay, sterility test (growing in liquid media), and epifluorescent microscopy. None of the cleaning protocols tested completely removed viable spores from the surface of the aluminum. In contrast, titanium was capable of being cleaned to sterility by two methods, the JPL standard and the commercial SAMS cleaning process. Further investigation showed that the passivation step employed in the JPL standard method is an effective surface sterilant on both metals but not compatible with aluminum. It is recommended that titanium (Ti 6Al-4V) be considered superior to aluminum (Al 6061) for use in spacecraft sampling hardware, both for its potential to be cleaned to sterilization and for its ability to withstand the most effective cleaning protocols.

Sample normalization methods in quantitative metabolomics.

Science.gov (United States)

Wu, Yiman; Li, Liang

2016-01-22

To reveal metabolomic changes caused by a biological event in quantitative metabolomics, it is critical to use an analytical tool that can perform accurate and precise quantification to examine the true concentration differences of individual metabolites found in different samples. A number of steps are involved in metabolomic analysis including pre-analytical work (e.g., sample collection and storage), analytical work (e.g., sample analysis) and data analysis (e.g., feature extraction and quantification). Each one of them can influence the quantitative results significantly and thus should be performed with great care. Among them, the total sample amount or concentration of metabolites can be significantly different from one sample to another. Thus, it is critical to reduce or eliminate the effect of total sample amount variation on quantification of individual metabolites. In this review, we describe the importance of sample normalization in the analytical workflow with a focus on mass spectrometry (MS)-based platforms, discuss a number of methods recently reported in the literature and comment on their applicability in real world metabolomics applications. Sample normalization has been sometimes ignored in metabolomics, partially due to the lack of a convenient means of performing sample normalization. We show that several methods are now available and sample normalization should be performed in quantitative metabolomics where the analyzed samples have significant variations in total sample amounts. Copyright © 2015 Elsevier B.V. All rights reserved.

Assessment of arsenic surface contamination in a museum anthropology department.

Science.gov (United States)

Gribovich, Andrey; Lacey, Steven; Franke, John; Hinkamp, David

2013-02-01

To assess potential arsenic (As) contamination of work surfaces to improve upon the control strategy at an anthropology department in a large natural history museum. Work practices were observed and control strategy reviewed to inform an occupational hygiene assessment strategy utilizing surface wipe sampling. A total of 35 sampling targets were identified, focusing on surfaces that receive high touch traffic, including workstations, artifact transport carts, and elevator buttons. Arsenic sampling and analysis were performed using reference method Occupational Safety and Health Administration ID-125G. Four of the sampling areas returned detectable levels of As, ranging from 0.052 to 0.350 μg/100 cm. Workplace observations and wipe sampling data enabled the development of recommendations to help to further reduce potential occupational exposure to As. Continuous reduction of surface contamination is prudent for known human carcinogens.

Radioactive air sampling methods

CERN Document Server

Maiello, Mark L

2010-01-01

Although the field of radioactive air sampling has matured and evolved over decades, it has lacked a single resource that assimilates technical and background information on its many facets. Edited by experts and with contributions from top practitioners and researchers, Radioactive Air Sampling Methods provides authoritative guidance on measuring airborne radioactivity from industrial, research, and nuclear power operations, as well as naturally occuring radioactivity in the environment. Designed for industrial hygienists, air quality experts, and heath physicists, the book delves into the applied research advancing and transforming practice with improvements to measurement equipment, human dose modeling of inhaled radioactivity, and radiation safety regulations. To present a wide picture of the field, it covers the international and national standards that guide the quality of air sampling measurements and equipment. It discusses emergency response issues, including radioactive fallout and the assets used ...

Environmental and Energy Quality Technologies. Task Order 0005: Organic Finishing Technologies, Sub Task 11: High Speed, Substrate Safe Specialty Coating Laser Stripping : Project: WP 2146

Science.gov (United States)

2015-06-22

79 Figure 72. Baseline Wipe Sample Collected From TEKA Hopper ...79 Figure 73. Wipe Sample Taken From TEKA Hopper after Laser Stripping ............................... 83 v Distribution A. Approved...in industrial applications. Fiber lasers are typically smaller and lighter in weight than traditional lasers, saving valuable floor space. While

ENVIRONMENTAL AND ENERGY QUALITY TECHNOLOGIES Task Order 0005: Organic Finishing Technologies Sub Task 11: High Speed, Substrate Safe Specialty Coating Laser Stripping

Science.gov (United States)

2015-06-22

79 Figure 72. Baseline Wipe Sample Collected From TEKA Hopper ...79 Figure 73. Wipe Sample Taken From TEKA Hopper after Laser Stripping ............................... 83 v Distribution A. Approved...in industrial applications. Fiber lasers are typically smaller and lighter in weight than traditional lasers, saving valuable floor space. While

Fluidics platform and method for sample preparation

Science.gov (United States)

Benner, Henry W.; Dzenitis, John M.

2016-06-21

Provided herein are fluidics platforms and related methods for performing integrated sample collection and solid-phase extraction of a target component of the sample all in one tube. The fluidics platform comprises a pump, particles for solid-phase extraction and a particle-holding means. The method comprises contacting the sample with one or more reagents in a pump, coupling a particle-holding means to the pump and expelling the waste out of the pump while the particle-holding means retains the particles inside the pump. The fluidics platform and methods herein described allow solid-phase extraction without pipetting and centrifugation.

Comparison studies of surface cleaning methods for PAN-based carbon fibers with acetone, supercritical acetone and subcritical alkali aqueous solutions

International Nuclear Information System (INIS)

Meng Linghui; Fan Dapeng; Huang Yudong; Jiang Zaixing; Zhang Chunhua

2012-01-01

Highlights: ► Cleaning with supercritical acetone is appropriate to wipe off the oxygenated contaminants. ► Cleaning with supercritical acetone causes smaller damage to bulk strength of carbon fibers. ► Cleaning with subcritical alkali aqueous solution can thoroughly remove silicious contaminants. - Abstract: Four kinds of polyacrylonitrile-based carbon fibers were cleaned by three methods and were characterized by X-ray photoelectron spectroscopy, monofilament tensile strength test and atomic force microscopy (AFM). Experimental results of these tests reveal that the method using supercritical acetone or subcritical potassium hydroxide aqueous solution act as the processing medium shows a better cleaning effect compared to the traditional method, Soxhlet extraction with acetone. The method using supercritical acetone is more appropriate to wipe off the oxygenated contaminants on carbon fibers’ surfaces and causes a relatively smaller damage to the bulk strength of each carbon fiber. As far as treating method using the subcritical alkali aqueous solution, it can thoroughly remove silicious contaminants on the surfaces of treated fibers.

Sampling Methods in Cardiovascular Nursing Research: An Overview.

Science.gov (United States)

Kandola, Damanpreet; Banner, Davina; O'Keefe-McCarthy, Sheila; Jassal, Debbie

2014-01-01

Cardiovascular nursing research covers a wide array of topics from health services to psychosocial patient experiences. The selection of specific participant samples is an important part of the research design and process. The sampling strategy employed is of utmost importance to ensure that a representative sample of participants is chosen. There are two main categories of sampling methods: probability and non-probability. Probability sampling is the random selection of elements from the population, where each element of the population has an equal and independent chance of being included in the sample. There are five main types of probability sampling including simple random sampling, systematic sampling, stratified sampling, cluster sampling, and multi-stage sampling. Non-probability sampling methods are those in which elements are chosen through non-random methods for inclusion into the research study and include convenience sampling, purposive sampling, and snowball sampling. Each approach offers distinct advantages and disadvantages and must be considered critically. In this research column, we provide an introduction to these key sampling techniques and draw on examples from the cardiovascular research. Understanding the differences in sampling techniques may aid nurses in effective appraisal of research literature and provide a reference pointfor nurses who engage in cardiovascular research.

On-capillary sample cleanup method for the electrophoretic determination of carbohydrates in juice samples.

Science.gov (United States)

Morales-Cid, Gabriel; Simonet, Bartolomé M; Cárdenas, Soledad; Valcárcel, Miguel

2007-05-01

On many occasions, sample treatment is a critical step in electrophoretic analysis. As an alternative to batch procedures, in this work, a new strategy is presented with a view to develop an on-capillary sample cleanup method. This strategy is based on the partial filling of the capillary with carboxylated single-walled carbon nanotube (c-SWNT). The nanoparticles retain interferences from the matrix allowing the determination and quantification of carbohydrates (viz glucose, maltose and fructose). The precision of the method for the analysis of real samples ranged from 5.3 to 6.4%. The proposed method was compared with a method based on a batch filtration of the juice sample through diatomaceous earth and further electrophoretic determination. This method was also validated in this work. The RSD for this other method ranged from 5.1 to 6%. The results obtained by both methods were statistically comparable demonstrating the accuracy of the proposed methods and their effectiveness. Electrophoretic separation of carbohydrates was achieved using 200 mM borate solution as a buffer at pH 9.5 and applying 15 kV. During separation, the capillary temperature was kept constant at 40 degrees C. For the on-capillary cleanup method, a solution containing 50 mg/L of c-SWNTs prepared in 300 mM borate solution at pH 9.5 was introduced for 60 s into the capillary just before sample introduction. For the electrophoretic analysis of samples cleaned in batch with diatomaceous earth, it is also recommended to introduce into the capillary, just before the sample, a 300 mM borate solution as it enhances the sensitivity and electrophoretic resolution.

Present status of NMCC and sample preparation method for bio-samples

International Nuclear Information System (INIS)

Futatsugawa, S.; Hatakeyama, S.; Saitou, S.; Sera, K.

1993-01-01

In NMCC(Nishina Memorial Cyclotron Center) we are doing researches on PET of nuclear medicine (Positron Emission Computed Tomography) and PIXE analysis (Particle Induced X-ray Emission) using a small cyclotron of compactly designed. The NMCC facilities have been opened to researchers of other institutions since April 1993. The present status of NMCC is described. Bio-samples (medical samples, plants, animals and environmental samples) have mainly been analyzed by PIXE in NMCC. Small amounts of bio-samples for PIXE are decomposed quickly and easily in a sealed PTFE (polytetrafluoroethylene) vessel with a microwave oven. This sample preparation method of bio-samples also is described. (author)

Evaluation of common methods for sampling invertebrate pollinator assemblages: net sampling out-perform pan traps.

Science.gov (United States)

Popic, Tony J; Davila, Yvonne C; Wardle, Glenda M

2013-01-01

Methods for sampling ecological assemblages strive to be efficient, repeatable, and representative. Unknowingly, common methods may be limited in terms of revealing species function and so of less value for comparative studies. The global decline in pollination services has stimulated surveys of flower-visiting invertebrates, using pan traps and net sampling. We explore the relative merits of these two methods in terms of species discovery, quantifying abundance, function, and composition, and responses of species to changing floral resources. Using a spatially-nested design we sampled across a 5000 km(2) area of arid grasslands, including 432 hours of net sampling and 1296 pan trap-days, between June 2010 and July 2011. Net sampling yielded 22% more species and 30% higher abundance than pan traps, and better reflected the spatio-temporal variation of floral resources. Species composition differed significantly between methods; from 436 total species, 25% were sampled by both methods, 50% only by nets, and the remaining 25% only by pans. Apart from being less comprehensive, if pan traps do not sample flower-visitors, the link to pollination is questionable. By contrast, net sampling functionally linked species to pollination through behavioural observations of flower-visitation interaction frequency. Netted specimens are also necessary for evidence of pollen transport. Benefits of net-based sampling outweighed minor differences in overall sampling effort. As pan traps and net sampling methods are not equivalent for sampling invertebrate-flower interactions, we recommend net sampling of invertebrate pollinator assemblages, especially if datasets are intended to document declines in pollination and guide measures to retain this important ecosystem service.

Direct sampling methods for inverse elastic scattering problems

Science.gov (United States)

Ji, Xia; Liu, Xiaodong; Xi, Yingxia

2018-03-01

We consider the inverse elastic scattering of incident plane compressional and shear waves from the knowledge of the far field patterns. Specifically, three direct sampling methods for location and shape reconstruction are proposed using the different component of the far field patterns. Only inner products are involved in the computation, thus the novel sampling methods are very simple and fast to be implemented. With the help of the factorization of the far field operator, we give a lower bound of the proposed indicator functionals for sampling points inside the scatterers. While for the sampling points outside the scatterers, we show that the indicator functionals decay like the Bessel functions as the sampling point goes away from the boundary of the scatterers. We also show that the proposed indicator functionals continuously dependent on the far field patterns, which further implies that the novel sampling methods are extremely stable with respect to data error. For the case when the observation directions are restricted into the limited aperture, we firstly introduce some data retrieval techniques to obtain those data that can not be measured directly and then use the proposed direct sampling methods for location and shape reconstructions. Finally, some numerical simulations in two dimensions are conducted with noisy data, and the results further verify the effectiveness and robustness of the proposed sampling methods, even for multiple multiscale cases and limited-aperture problems.

Detection of Illicit Drugs on Surfaces Using Direct Analysis in Real Time (DART)/Time-of-Flight Mass Spectrometry

Science.gov (United States)

Methamphetamine (meth) residues from meth syntheses or habitual meth smoking pose human health hazards. State health departments require remediation of meth labs before properties are sold. NIOSH methods for meth analysis require wipe sampling, extraction, cleanup, solvent excha...

A Noise Reduction Method for Dual-Mass Micro-Electromechanical Gyroscopes Based on Sample Entropy Empirical Mode Decomposition and Time-Frequency Peak Filtering.

Science.gov (United States)

Shen, Chong; Li, Jie; Zhang, Xiaoming; Shi, Yunbo; Tang, Jun; Cao, Huiliang; Liu, Jun

2016-05-31

The different noise components in a dual-mass micro-electromechanical system (MEMS) gyroscope structure is analyzed in this paper, including mechanical-thermal noise (MTN), electronic-thermal noise (ETN), flicker noise (FN) and Coriolis signal in-phase noise (IPN). The structure equivalent electronic model is established, and an improved white Gaussian noise reduction method for dual-mass MEMS gyroscopes is proposed which is based on sample entropy empirical mode decomposition (SEEMD) and time-frequency peak filtering (TFPF). There is a contradiction in TFPS, i.e., selecting a short window length may lead to good preservation of signal amplitude but bad random noise reduction, whereas selecting a long window length may lead to serious attenuation of the signal amplitude but effective random noise reduction. In order to achieve a good tradeoff between valid signal amplitude preservation and random noise reduction, SEEMD is adopted to improve TFPF. Firstly, the original signal is decomposed into intrinsic mode functions (IMFs) by EMD, and the SE of each IMF is calculated in order to classify the numerous IMFs into three different components; then short window TFPF is employed for low frequency component of IMFs, and long window TFPF is employed for high frequency component of IMFs, and the noise component of IMFs is wiped off directly; at last the final signal is obtained after reconstruction. Rotation experimental and temperature experimental are carried out to verify the proposed SEEMD-TFPF algorithm, the verification and comparison results show that the de-noising performance of SEEMD-TFPF is better than that achievable with the traditional wavelet, Kalman filter and fixed window length TFPF methods.

A Noise Reduction Method for Dual-Mass Micro-Electromechanical Gyroscopes Based on Sample Entropy Empirical Mode Decomposition and Time-Frequency Peak Filtering

Directory of Open Access Journals (Sweden)

Chong Shen

2016-05-01

Full Text Available The different noise components in a dual-mass micro-electromechanical system (MEMS gyroscope structure is analyzed in this paper, including mechanical-thermal noise (MTN, electronic-thermal noise (ETN, flicker noise (FN and Coriolis signal in-phase noise (IPN. The structure equivalent electronic model is established, and an improved white Gaussian noise reduction method for dual-mass MEMS gyroscopes is proposed which is based on sample entropy empirical mode decomposition (SEEMD and time-frequency peak filtering (TFPF. There is a contradiction in TFPS, i.e., selecting a short window length may lead to good preservation of signal amplitude but bad random noise reduction, whereas selecting a long window length may lead to serious attenuation of the signal amplitude but effective random noise reduction. In order to achieve a good tradeoff between valid signal amplitude preservation and random noise reduction, SEEMD is adopted to improve TFPF. Firstly, the original signal is decomposed into intrinsic mode functions (IMFs by EMD, and the SE of each IMF is calculated in order to classify the numerous IMFs into three different components; then short window TFPF is employed for low frequency component of IMFs, and long window TFPF is employed for high frequency component of IMFs, and the noise component of IMFs is wiped off directly; at last the final signal is obtained after reconstruction. Rotation experimental and temperature experimental are carried out to verify the proposed SEEMD-TFPF algorithm, the verification and comparison results show that the de-noising performance of SEEMD-TFPF is better than that achievable with the traditional wavelet, Kalman filter and fixed window length TFPF methods.

2008 Homeland Security S and T Stakeholders Conference West volume 2 Monday

Science.gov (United States)

2008-01-16

surfaces and eliminate wiping of surfaces ( manual sampling issues, cost of consumables, etc.). • Ability to detect threats with Trace Explosive...ability to sample. - Non-contact (if possible) - to reduce interaction with surfaces and eliminate wiping of surfaces ( manual sampling issues, cost of...for Good and Evil Knowledge of Pathogenic Disease Mechanisms HTP (high throughput lab processing Microbe Gene, Protein Sequencing New

Sampling Methods for Wallenius' and Fisher's Noncentral Hypergeometric Distributions

DEFF Research Database (Denmark)

Fog, Agner

2008-01-01

the mode, ratio-of-uniforms rejection method, and rejection by sampling in the tau domain. Methods for the multivariate distributions include: simulation of urn experiments, conditional method, Gibbs sampling, and Metropolis-Hastings sampling. These methods are useful for Monte Carlo simulation of models...... of biased sampling and models of evolution and for calculating moments and quantiles of the distributions.......Several methods for generating variates with univariate and multivariate Wallenius' and Fisher's noncentral hypergeometric distributions are developed. Methods for the univariate distributions include: simulation of urn experiments, inversion by binary search, inversion by chop-down search from...

Evaluation of common methods for sampling invertebrate pollinator assemblages: net sampling out-perform pan traps.

Directory of Open Access Journals (Sweden)

Tony J Popic

Full Text Available Methods for sampling ecological assemblages strive to be efficient, repeatable, and representative. Unknowingly, common methods may be limited in terms of revealing species function and so of less value for comparative studies. The global decline in pollination services has stimulated surveys of flower-visiting invertebrates, using pan traps and net sampling. We explore the relative merits of these two methods in terms of species discovery, quantifying abundance, function, and composition, and responses of species to changing floral resources. Using a spatially-nested design we sampled across a 5000 km(2 area of arid grasslands, including 432 hours of net sampling and 1296 pan trap-days, between June 2010 and July 2011. Net sampling yielded 22% more species and 30% higher abundance than pan traps, and better reflected the spatio-temporal variation of floral resources. Species composition differed significantly between methods; from 436 total species, 25% were sampled by both methods, 50% only by nets, and the remaining 25% only by pans. Apart from being less comprehensive, if pan traps do not sample flower-visitors, the link to pollination is questionable. By contrast, net sampling functionally linked species to pollination through behavioural observations of flower-visitation interaction frequency. Netted specimens are also necessary for evidence of pollen transport. Benefits of net-based sampling outweighed minor differences in overall sampling effort. As pan traps and net sampling methods are not equivalent for sampling invertebrate-flower interactions, we recommend net sampling of invertebrate pollinator assemblages, especially if datasets are intended to document declines in pollination and guide measures to retain this important ecosystem service.

DOE methods for evaluating environmental and waste management samples

International Nuclear Information System (INIS)

Goheen, S.C.; McCulloch, M.; Thomas, B.L.; Riley, R.G.; Sklarew, D.S.; Mong, G.M.; Fadeff, S.K.

1993-03-01

DOE Methods for Evaluating Environmental and Waste Management Samples (DOE Methods) provides applicable methods in use by. the US Department of Energy (DOE) laboratories for sampling and analyzing constituents of waste and environmental samples. The development of DOE Methods is supported by the Laboratory Management Division (LMD) of the DOE. This document contains chapters and methods that are proposed for use in evaluating components of DOE environmental and waste management samples. DOE Methods is a resource intended to support sampling and analytical activities that will aid in defining the type and breadth of contamination and thus determine the extent of environmental restoration or waste management actions needed, as defined by the DOE, the US Environmental Protection Agency (EPA), or others

DOE methods for evaluating environmental and waste management samples.

Energy Technology Data Exchange (ETDEWEB)

Goheen, S C; McCulloch, M; Thomas, B L; Riley, R G; Sklarew, D S; Mong, G M; Fadeff, S K [eds.; Pacific Northwest Lab., Richland, WA (United States)

1994-04-01

DOE Methods for Evaluating Environmental and Waste Management Samples (DOE Methods) provides applicable methods in use by. the US Department of Energy (DOE) laboratories for sampling and analyzing constituents of waste and environmental samples. The development of DOE Methods is supported by the Laboratory Management Division (LMD) of the DOE. This document contains chapters and methods that are proposed for use in evaluating components of DOE environmental and waste management samples. DOE Methods is a resource intended to support sampling and analytical activities that will aid in defining the type and breadth of contamination and thus determine the extent of environmental restoration or waste management actions needed, as defined by the DOE, the US Environmental Protection Agency (EPA), or others.

Association between occupational exposure levels of antineoplastic drugs and work environment in five hospitals in Japan.

Science.gov (United States)

Yoshida, Jin; Koda, Shigeki; Nishida, Shozo; Yoshida, Toshiaki; Miyajima, Keiko; Kumagai, Shinji

2011-03-01

The aim of the present study was to evaluate the measurement of contamination by antineoplastic drugs for safer handling of such drugs by medical workers. We investigated the relationship between the contamination level of antineoplastic drugs and the conditions of their handling. Air samples and wipe samples were collected from equipment in the preparation rooms of five hospitals (hospitals A-E). These samples were subjected to measurement of the amounts of cyclophosphamide (CPA), fluorouracil (5FU), gemcitabine (GEM), and platinum-containing drugs (Pt). Twenty-four-hour urine samples were collected from the pharmacists who handled or audited, the antineoplastic drugs were analyzed for CPA and Pt. Pt was detected from air samples inside BSC in hospital B. Antineoplastic drugs were detected from wipe samples of the BSC in hospitals A, B, D, and E and of other equipment in the preparation rooms in hospitals A, B, C, and D. Cyclophosphamide and 5FU were detected from wipe samples of the air-conditioner filter in hospital A, and CPA was detected from that in hospital D. Cyclophosphamide was detected from urine samples of workers in hospitals B, D, and E. The contamination level of antineoplastic drugs was suggested to be related with the amount of drugs handled, cleaning methods of the equipment, and the skill level of the technique of maintaining negative pressure inside a vial. In order to reduce the contamination and exposure to antineoplastic drugs in the hospital work environment very close to zero, comprehensive safety precautions, including adequate mixing and cleaning methods was required in addition to BSC and closed system device.

Failure Probability Calculation Method Using Kriging Metamodel-based Importance Sampling Method

Energy Technology Data Exchange (ETDEWEB)

Lee, Seunggyu [Korea Aerospace Research Institue, Daejeon (Korea, Republic of); Kim, Jae Hoon [Chungnam Nat’l Univ., Daejeon (Korea, Republic of)

2017-05-15

The kernel density was determined based on sampling points obtained in a Markov chain simulation and was assumed to be an important sampling function. A Kriging metamodel was constructed in more detail in the vicinity of a limit state. The failure probability was calculated based on importance sampling, which was performed for the Kriging metamodel. A pre-existing method was modified to obtain more sampling points for a kernel density in the vicinity of a limit state. A stable numerical method was proposed to find a parameter of the kernel density. To assess the completeness of the Kriging metamodel, the possibility of changes in the calculated failure probability due to the uncertainty of the Kriging metamodel was calculated.

40 CFR Appendix I to Part 261 - Representative Sampling Methods

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 25 2010-07-01 2010-07-01 false Representative Sampling Methods I...—Representative Sampling Methods The methods and equipment used for sampling waste materials will vary with the form and consistency of the waste materials to be sampled. Samples collected using the sampling...

Mixed Methods Sampling: A Typology with Examples

Science.gov (United States)

Teddlie, Charles; Yu, Fen

2007-01-01

This article presents a discussion of mixed methods (MM) sampling techniques. MM sampling involves combining well-established qualitative and quantitative techniques in creative ways to answer research questions posed by MM research designs. Several issues germane to MM sampling are presented including the differences between probability and…

Log sampling methods and software for stand and landscape analyses.

Science.gov (United States)

Lisa J. Bate; Torolf R. Torgersen; Michael J. Wisdom; Edward O. Garton; Shawn C. Clabough

2008-01-01

We describe methods for efficient, accurate sampling of logs at landscape and stand scales to estimate density, total length, cover, volume, and weight. Our methods focus on optimizing the sampling effort by choosing an appropriate sampling method and transect length for specific forest conditions and objectives. Sampling methods include the line-intersect method and...

New methods for sampling sparse populations

Science.gov (United States)

Anna Ringvall

2007-01-01

To improve surveys of sparse objects, methods that use auxiliary information have been suggested. Guided transect sampling uses prior information, e.g., from aerial photographs, for the layout of survey strips. Instead of being laid out straight, the strips will wind between potentially more interesting areas. 3P sampling (probability proportional to prediction) uses...

Statistical sampling method for releasing decontaminated vehicles

International Nuclear Information System (INIS)

Lively, J.W.; Ware, J.A.

1996-01-01

Earth moving vehicles (e.g., dump trucks, belly dumps) commonly haul radiologically contaminated materials from a site being remediated to a disposal site. Traditionally, each vehicle must be surveyed before being released. The logistical difficulties of implementing the traditional approach on a large scale demand that an alternative be devised. A statistical method (MIL-STD-105E, open-quotes Sampling Procedures and Tables for Inspection by Attributesclose quotes) for assessing product quality from a continuous process was adapted to the vehicle decontamination process. This method produced a sampling scheme that automatically compensates and accommodates fluctuating batch sizes and changing conditions without the need to modify or rectify the sampling scheme in the field. Vehicles are randomly selected (sampled) upon completion of the decontamination process to be surveyed for residual radioactive surface contamination. The frequency of sampling is based on the expected number of vehicles passing through the decontamination process in a given period and the confidence level desired. This process has been successfully used for 1 year at the former uranium mill site in Monticello, Utah (a CERCLA regulated clean-up site). The method forces improvement in the quality of the decontamination process and results in a lower likelihood that vehicles exceeding the surface contamination standards are offered for survey. Implementation of this statistical sampling method on Monticello Projects has resulted in more efficient processing of vehicles through decontamination and radiological release, saved hundreds of hours of processing time, provided a high level of confidence that release limits are met, and improved the radiological cleanliness of vehicles leaving the controlled site

19 CFR 151.70 - Method of sampling by Customs.

Science.gov (United States)

2010-04-01

... 19 Customs Duties 2 2010-04-01 2010-04-01 false Method of sampling by Customs. 151.70 Section 151... THE TREASURY (CONTINUED) EXAMINATION, SAMPLING, AND TESTING OF MERCHANDISE Wool and Hair § 151.70 Method of sampling by Customs. A general sample shall be taken from each sampling unit, unless it is not...

Microvolume protein concentration determination using the NanoDrop 2000c spectrophotometer.

Science.gov (United States)

Desjardins, Philippe; Hansen, Joel B; Allen, Michael

2009-11-04

Traditional spectrophotometry requires placing samples into cuvettes or capillaries. This is often impractical due to the limited sample volumes often used for protein analysis. The Thermo Scientific NanoDrop 2000c Spectrophotometer solves this issue with an innovative sample retention system that holds microvolume samples between two measurement surfaces using the surface tension properties of liquids, enabling the quantification of samples in volumes as low as 0.5-2 microL. The elimination of cuvettes or capillaries allows real time changes in path length, which reduces the measurement time while greatly increasing the dynamic range of protein concentrations that can be measured. The need for dilutions is also eliminated, and preparations for sample quantification are relatively easy as the measurement surfaces can be simply wiped with laboratory wipe. This video article presents modifications to traditional protein concentration determination methods for quantification of microvolume amounts of protein using A280 absorbance readings or the BCA colorimetric assay.

Innovative methods for inorganic sample preparation

Energy Technology Data Exchange (ETDEWEB)

Essling, A.M.; Huff, E.A.; Graczyk, D.G.

1992-04-01

Procedures and guidelines are given for the dissolution of a variety of selected materials using fusion, microwave, and Parr bomb techniques. These materials include germanium glass, corium-concrete mixtures, and zeolites. Emphasis is placed on sample-preparation approaches that produce a single master solution suitable for complete multielement characterization of the sample. In addition, data are presented on the soil microwave digestion method approved by the Environmental Protection Agency (EPA). Advantages and disadvantages of each sample-preparation technique are summarized.

Innovative methods for inorganic sample preparation

International Nuclear Information System (INIS)

Essling, A.M.; Huff, E.A.; Graczyk, D.G.

1992-04-01

Procedures and guidelines are given for the dissolution of a variety of selected materials using fusion, microwave, and Parr bomb techniques. These materials include germanium glass, corium-concrete mixtures, and zeolites. Emphasis is placed on sample-preparation approaches that produce a single master solution suitable for complete multielement characterization of the sample. In addition, data are presented on the soil microwave digestion method approved by the Environmental Protection Agency (EPA). Advantages and disadvantages of each sample-preparation technique are summarized

Chapter 12. Sampling and analytical methods

International Nuclear Information System (INIS)

Busenberg, E.; Plummer, L.N.; Cook, P.G.; Solomon, D.K.; Han, L.F.; Groening, M.; Oster, H.

2006-01-01

When water samples are taken for the analysis of CFCs, regardless of the sampling method used, contamination of samples by contact with atmospheric air (with its 'high' CFC concentrations) is a major concern. This is because groundwaters usually have lower CFC concentrations than those waters which have been exposed to the modern air. Some groundwaters might not contain CFCs and, therefore, are most sensitive to trace contamination by atmospheric air. Thus, extreme precautions are needed to obtain uncontaminated samples when groundwaters, particularly those with older ages, are sampled. It is recommended at the start of any CFC investigation that samples from a CFC-free source be collected and analysed, as a check upon the sampling equipment and methodology. The CFC-free source might be a deep monitoring well or, alternatively, CFC-free water could be carefully prepared in the laboratory. It is especially important that all tubing, pumps and connection that will be used in the sampling campaign be checked in this manner

Degreasing method for the seborrheic areas with respect to regaining sebum excretion rate to casual level.

Science.gov (United States)

Rode, Birgitte; Ivens, Ulla; Serup, Jørgen

2000-05-01

BACKGROUND/AIMS: Sebum excreted from the seborrheic glands keeps the skin surface subtle and moist. Before determining the activity of seborrheic glands, the skin surface must be degreased to remove contamination but without provoking sebum excretion. The purpose of this study was to set up a standardised degreasing procedure for various seborrheic areas in different skin types. The method will take day-to-day variations into account with respect to the kinetics of refatting. METHODS: The Sebumeter(R) from Courage+Khazaka is used to quantify the sebum excretion. Day-to-day variations were measured on the forehead in groups of 12 volunteers on 2 consecutive days. The degreasing procedure was investigated by individual cleaning with alcohol compared to washing with a mild detergent followed by wipes with alcohol on the forehead. The degree of refatting was monitored until 3 h after defatting on seborrheic areas: the forehead, cheek, nose, chin and upper back. RESULTS: There was no statistical significant difference in the variation from day to day (Pskin types was observed. An individual difference in the number of alcoholic wipes needed to degrease the forehead was seen. Washing followed by several repetitions of alcoholic wipes was not sufficient for the forehead, chin and nose (P>0.05). For the cheek and upper back, it was sufficient to wash with soap (Pskin until the sebum output reached the casual level was 2 h (P>0.05). The area under the curve (AUC) indicates that individual skin types return to casual level after defatting. CONCLUSION: There was no statistically significant day-to-day variation using the Sebumeter(R). We ended up with different degreasing procedures in different seborrheic areas. Washing gently with a detergent solution and then performing three wipes with alcohol was optimal for degreasing the forehead, nose and chin. For the cheek and upper back, it was sufficient to use a mild soap. Casual level was reached after 2 h in all seborrheic

Sampling methods for low-frequency electromagnetic imaging

International Nuclear Information System (INIS)

Gebauer, Bastian; Hanke, Martin; Schneider, Christoph

2008-01-01

For the detection of hidden objects by low-frequency electromagnetic imaging the linear sampling method works remarkably well despite the fact that the rigorous mathematical justification is still incomplete. In this work, we give an explanation for this good performance by showing that in the low-frequency limit the measurement operator fulfils the assumptions for the fully justified variant of the linear sampling method, the so-called factorization method. We also show how the method has to be modified in the physically relevant case of electromagnetic imaging with divergence-free currents. We present numerical results to illustrate our findings, and to show that similar performance can be expected for the case of conducting objects and layered backgrounds

Statistical Analyses of Second Indoor Bio-Release Field Evaluation Study at Idaho National Laboratory

Energy Technology Data Exchange (ETDEWEB)

Amidan, Brett G.; Pulsipher, Brent A.; Matzke, Brett D.

2009-12-17

In September 2008 a large-scale testing operation (referred to as the INL-2 test) was performed within a two-story building (PBF-632) at the Idaho National Laboratory (INL). The report “Operational Observations on the INL-2 Experiment” defines the seven objectives for this test and discusses the results and conclusions. This is further discussed in the introduction of this report. The INL-2 test consisted of five tests (events) in which a floor (level) of the building was contaminated with the harmless biological warfare agent simulant Bg and samples were taken in most, if not all, of the rooms on the contaminated floor. After the sampling, the building was decontaminated, and the next test performed. Judgmental samples and probabilistic samples were determined and taken during each test. Vacuum, wipe, and swab samples were taken within each room. The purpose of this report is to study an additional four topics that were not within the scope of the original report. These topics are: 1) assess the quantitative assumptions about the data being normally or log-normally distributed; 2) evaluate differences and quantify the sample to sample variability within a room and across the rooms; 3) perform geostatistical types of analyses to study spatial correlations; and 4) quantify the differences observed between surface types and sampling methods for each scenario and study the consistency across the scenarios. The following four paragraphs summarize the results of each of the four additional analyses. All samples after decontamination came back negative. Because of this, it was not appropriate to determine if these clearance samples were normally distributed. As Table 1 shows, the characterization data consists of values between and inclusive of 0 and 100 CFU/cm2 (100 was the value assigned when the number is too numerous to count). The 100 values are generally much bigger than the rest of the data, causing the data to be right skewed. There are also a significant

Occupational hand eczema caused by nickel and evaluated by quantitative exposure assessment.

Science.gov (United States)

Jensen, Peter; Thyssen, Jacob P; Johansen, Jeanne D; Skare, Lizbet; Menné, Torkil; Lidén, Carola

2011-01-01

EU legislation has reduced the epidemic of nickel contact allergy affecting the consumer, and shifted the focus towards occupational exposure. The acid wipe sampling technique was developed to quantitatively determine skin exposure to metals. To assess the clinical usefulness of the acid wipe sampling technique as part of the diagnostic investigation for occupational nickel allergy-associated hand dermatitis. Six patients with vesicular dermatitis on the hands were included. Acid wipe sampling of skin and patch testing with a nickel sulfate dilution series were performed. Nickel was detected in all samples from the hands. In all patients, the nickel content on the hands was higher than on the non-exposed control area. Occupational exposure to nickel-releasing items raised the nickel content on exposed skin as compared with a non-exposed control site. Nickel-reducing measures led to complete symptom relief in all cases. In cases of a positive nickel patch test reaction and hand eczema, patients should perform the dimethylglyoxime (DMG) test on metallic items at home and at work. The acid wipe sampling technique is useful for the diagnosis of occupational hand eczema following screening with the inexpensive DMG test. © 2010 John Wiley & Sons A/S.

Comparability of river suspended-sediment sampling and laboratory analysis methods

Science.gov (United States)

Groten, Joel T.; Johnson, Gregory D.

2018-03-06

Accurate measurements of suspended sediment, a leading water-quality impairment in many Minnesota rivers, are important for managing and protecting water resources; however, water-quality standards for suspended sediment in Minnesota are based on grab field sampling and total suspended solids (TSS) laboratory analysis methods that have underrepresented concentrations of suspended sediment in rivers compared to U.S. Geological Survey equal-width-increment or equal-discharge-increment (EWDI) field sampling and suspended sediment concentration (SSC) laboratory analysis methods. Because of this underrepresentation, the U.S. Geological Survey, in collaboration with the Minnesota Pollution Control Agency, collected concurrent grab and EWDI samples at eight sites to compare results obtained using different combinations of field sampling and laboratory analysis methods.Study results determined that grab field sampling and TSS laboratory analysis results were biased substantially low compared to EWDI sampling and SSC laboratory analysis results, respectively. Differences in both field sampling and laboratory analysis methods caused grab and TSS methods to be biased substantially low. The difference in laboratory analysis methods was slightly greater than field sampling methods.Sand-sized particles had a strong effect on the comparability of the field sampling and laboratory analysis methods. These results indicated that grab field sampling and TSS laboratory analysis methods fail to capture most of the sand being transported by the stream. The results indicate there is less of a difference among samples collected with grab field sampling and analyzed for TSS and concentration of fines in SSC. Even though differences are present, the presence of strong correlations between SSC and TSS concentrations provides the opportunity to develop site specific relations to address transport processes not captured by grab field sampling and TSS laboratory analysis methods.

Sampling of temporal networks: Methods and biases

Science.gov (United States)

Rocha, Luis E. C.; Masuda, Naoki; Holme, Petter

2017-11-01

Temporal networks have been increasingly used to model a diversity of systems that evolve in time; for example, human contact structures over which dynamic processes such as epidemics take place. A fundamental aspect of real-life networks is that they are sampled within temporal and spatial frames. Furthermore, one might wish to subsample networks to reduce their size for better visualization or to perform computationally intensive simulations. The sampling method may affect the network structure and thus caution is necessary to generalize results based on samples. In this paper, we study four sampling strategies applied to a variety of real-life temporal networks. We quantify the biases generated by each sampling strategy on a number of relevant statistics such as link activity, temporal paths and epidemic spread. We find that some biases are common in a variety of networks and statistics, but one strategy, uniform sampling of nodes, shows improved performance in most scenarios. Given the particularities of temporal network data and the variety of network structures, we recommend that the choice of sampling methods be problem oriented to minimize the potential biases for the specific research questions on hand. Our results help researchers to better design network data collection protocols and to understand the limitations of sampled temporal network data.

Neonatal blood gas sampling methods | Goenka | South African ...

African Journals Online (AJOL)

There is little published guidance that systematically evaluates the different methods of neonatal blood gas sampling, where each method has its individual benefits and risks. This review critically surveys the available evidence to generate a comparison between arterial and capillary blood gas sampling, focusing on their ...

An improved selective sampling method

International Nuclear Information System (INIS)

Miyahara, Hiroshi; Iida, Nobuyuki; Watanabe, Tamaki

1986-01-01

The coincidence methods which are currently used for the accurate activity standardisation of radio-nuclides, require dead time and resolving time corrections which tend to become increasingly uncertain as countrates exceed about 10 K. To reduce the dependence on such corrections, Muller, in 1981, proposed the selective sampling method using a fast multichannel analyser (50 ns ch -1 ) for measuring the countrates. It is, in many ways, more convenient and possibly potentially more reliable to replace the MCA with scalers and a circuit is described employing five scalers; two of them serving to measure the background correction. Results of comparisons using our new method and the coincidence method for measuring the activity of 60 Co sources yielded agree-ment within statistical uncertainties. (author)

An algorithm to improve sampling efficiency for uncertainty propagation using sampling based method

International Nuclear Information System (INIS)

Campolina, Daniel; Lima, Paulo Rubens I.; Pereira, Claubia; Veloso, Maria Auxiliadora F.

2015-01-01

Sample size and computational uncertainty were varied in order to investigate sample efficiency and convergence of the sampling based method for uncertainty propagation. Transport code MCNPX was used to simulate a LWR model and allow the mapping, from uncertain inputs of the benchmark experiment, to uncertain outputs. Random sampling efficiency was improved through the use of an algorithm for selecting distributions. Mean range, standard deviation range and skewness were verified in order to obtain a better representation of uncertainty figures. Standard deviation of 5 pcm in the propagated uncertainties for 10 n-samples replicates was adopted as convergence criterion to the method. Estimation of 75 pcm uncertainty on reactor k eff was accomplished by using sample of size 93 and computational uncertainty of 28 pcm to propagate 1σ uncertainty of burnable poison radius. For a fixed computational time, in order to reduce the variance of the uncertainty propagated, it was found, for the example under investigation, it is preferable double the sample size than double the amount of particles followed by Monte Carlo process in MCNPX code. (author)

DOE methods for evaluating environmental and waste management samples

International Nuclear Information System (INIS)

Goheen, S.C.; McCulloch, M.; Thomas, B.L.; Riley, R.G.; Sklarew, D.S.; Mong, G.M.; Fadeff, S.K.

1994-04-01

DOE Methods for Evaluating Environmental and Waste Management Samples (DOE Methods) is a resource intended to support sampling and analytical activities for the evaluation of environmental and waste management samples from U.S. Department of Energy (DOE) sites. DOE Methods is the result of extensive cooperation from all DOE analytical laboratories. All of these laboratories have contributed key information and provided technical reviews as well as significant moral support leading to the success of this document. DOE Methods is designed to encompass methods for collecting representative samples and for determining the radioisotope activity and organic and inorganic composition of a sample. These determinations will aid in defining the type and breadth of contamination and thus determine the extent of environmental restoration or waste management actions needed, as defined by the DOE, the U.S. Environmental Protection Agency, or others. The development of DOE Methods is supported by the Laboratory Management Division of the DOE. Methods are prepared for entry into DOE Methods as chapter editors, together with DOE and other participants in this program, identify analytical and sampling method needs. Unique methods or methods consolidated from similar procedures in the DOE Procedures Database are selected for potential inclusion in this document. Initial selection is based largely on DOE needs and procedure applicability and completeness. Methods appearing in this document are one of two types. open-quotes Draftclose quotes or open-quotes Verified.close quotes. open-quotes Draftclose quotes methods that have been reviewed internally and show potential for eventual verification are included in this document, but they have not been reviewed externally, and their precision and bias may not be known. open-quotes Verifiedclose quotes methods in DOE Methods have been reviewed by volunteers from various DOE sites and private corporations

A Method for Choosing the Best Samples for Mars Sample Return.

Science.gov (United States)

Gordon, Peter R; Sephton, Mark A

2018-05-01

Success of a future Mars Sample Return mission will depend on the correct choice of samples. Pyrolysis-FTIR can be employed as a triage instrument for Mars Sample Return. The technique can thermally dissociate minerals and organic matter for detection. Identification of certain mineral types can determine the habitability of the depositional environment, past or present, while detection of organic matter may suggest past or present habitation. In Mars' history, the Theiikian era represents an attractive target for life search missions and the acquisition of samples. The acidic and increasingly dry Theiikian may have been habitable and followed a lengthy neutral and wet period in Mars' history during which life could have originated and proliferated to achieve relatively abundant levels of biomass with a wide distribution. Moreover, the sulfate minerals produced in the Theiikian are also known to be good preservers of organic matter. We have used pyrolysis-FTIR and samples from a Mars analog ferrous acid stream with a thriving ecosystem to test the triage concept. Pyrolysis-FTIR identified those samples with the greatest probability of habitability and habitation. A three-tier scoring system was developed based on the detection of (i) organic signals, (ii) carbon dioxide and water, and (iii) sulfur dioxide. The presence of each component was given a score of A, B, or C depending on whether the substance had been detected, tentatively detected, or not detected, respectively. Single-step (for greatest possible sensitivity) or multistep (for more diagnostic data) pyrolysis-FTIR methods informed the assignments. The system allowed the highest-priority samples to be categorized as AAA (or A*AA if the organic signal was complex), while the lowest-priority samples could be categorized as CCC. Our methods provide a mechanism with which to rank samples and identify those that should take the highest priority for return to Earth during a Mars Sample Return mission. Key Words

Sample preparation method for scanning force microscopy

CERN Document Server

Jankov, I R; Szente, R N; Carreno, M N P; Swart, J W; Landers, R

2001-01-01

We present a method of sample preparation for studies of ion implantation on metal surfaces. The method, employing a mechanical mask, is specially adapted for samples analysed by Scanning Force Microscopy. It was successfully tested on polycrystalline copper substrates implanted with phosphorus ions at an acceleration voltage of 39 keV. The changes of the electrical properties of the surface were measured by Kelvin Probe Force Microscopy and the surface composition was analysed by Auger Electron Spectroscopy.

Sampling and analysis methods for geothermal fluids and gases

Energy Technology Data Exchange (ETDEWEB)

Watson, J.C.

1978-07-01

The sampling procedures for geothermal fluids and gases include: sampling hot springs, fumaroles, etc.; sampling condensed brine and entrained gases; sampling steam-lines; low pressure separator systems; high pressure separator systems; two-phase sampling; downhole samplers; and miscellaneous methods. The recommended analytical methods compiled here cover physical properties, dissolved solids, and dissolved and entrained gases. The sequences of methods listed for each parameter are: wet chemical, gravimetric, colorimetric, electrode, atomic absorption, flame emission, x-ray fluorescence, inductively coupled plasma-atomic emission spectroscopy, ion exchange chromatography, spark source mass spectrometry, neutron activation analysis, and emission spectrometry. Material on correction of brine component concentrations for steam loss during flashing is presented. (MHR)

Comparing residential contamination in a Houston environmental justice neighborhood before and after Hurricane Harvey.

Science.gov (United States)

Horney, Jennifer A; Casillas, Gaston A; Baker, Erin; Stone, Kahler W; Kirsch, Katie R; Camargo, Krisa; Wade, Terry L; McDonald, Thomas J

2018-01-01

Polycyclic aromatic hydrocarbons (PAHs) are complex environmental toxicants. Exposure to them has been linked to adverse health outcomes including cancer, as well as diseases of the skin, liver, and immune system. Based on an ongoing community engagement partnership with stakeholder groups and residents, we conducted a small longitudinal study to assess domestic exposure to PAHs among residents of Manchester, an environmental justice neighborhood located in the East End of Houston, TX. In December, 2016, we used fiber wipes to collect samples of household dust from 25 homes in Manchester. Following Hurricane Harvey, in September 2017, we revisited 24 of the 25 homes to collect soil samples from the front yards of the same homes. Wipes and soil were analyzed for the presence of PAHs using gas chromatography-mass spectrometry (GC-MS) methods. Principal component analysis plots, heatmaps, and PAH ratios were used to compare pre- and post-Hurricane Harvey samples. While direct comparison is not possible, we present three methods for comparing PAHs found in pre-hurricane fiber wipes and post-hurricane soil samples. The methods demonstrate that the PAHs found before and after Hurricane Harvey are likely from similar sources and that those sources are most likely to be associated with combustion. We also found evidence of redistribution of PAHs due to extreme flooding associated with Hurricane Harvey. Residents of the Manchester neighborhood of Houston, TX, are exposed to a range of PAHs in household dust and outdoor soil. While it was not possible to compare directly, we were able to use several methods to assess detected concentrations, changes in site-specific PAH allocations, and PAH origination. Additional research is needed to identify specific sources of domestic PAH exposure in these communities and continued work involving community members and policy makers should aim to develop interventions to reduce domestic exposure to and prevent negative health outcomes

On Angular Sampling Methods for 3-D Spatial Channel Models

DEFF Research Database (Denmark)

Fan, Wei; Jämsä, Tommi; Nielsen, Jesper Ødum

2015-01-01

This paper discusses generating three dimensional (3D) spatial channel models with emphasis on the angular sampling methods. Three angular sampling methods, i.e. modified uniform power sampling, modified uniform angular sampling, and random pairing methods are proposed and investigated in detail....... The random pairing method, which uses only twenty sinusoids in the ray-based model for generating the channels, presents good results if the spatial channel cluster is with a small elevation angle spread. For spatial clusters with large elevation angle spreads, however, the random pairing method would fail...... and the other two methods should be considered....

Interval sampling methods and measurement error: a computer simulation.

Science.gov (United States)

Wirth, Oliver; Slaven, James; Taylor, Matthew A

2014-01-01

A simulation study was conducted to provide a more thorough account of measurement error associated with interval sampling methods. A computer program simulated the application of momentary time sampling, partial-interval recording, and whole-interval recording methods on target events randomly distributed across an observation period. The simulation yielded measures of error for multiple combinations of observation period, interval duration, event duration, and cumulative event duration. The simulations were conducted up to 100 times to yield measures of error variability. Although the present simulation confirmed some previously reported characteristics of interval sampling methods, it also revealed many new findings that pertain to each method's inherent strengths and weaknesses. The analysis and resulting error tables can help guide the selection of the most appropriate sampling method for observation-based behavioral assessments. © Society for the Experimental Analysis of Behavior.

Product screening for sources of halogenated flame retardants in Canadian house and office dust

Energy Technology Data Exchange (ETDEWEB)

Abbasi, Golnoush [Department of Geography, University of Toronto, 100 St. George St., Toronto M5S 3G3 (Canada); Saini, Amandeep [Department of Physical and Environmental Sciences, University of Toronto, 1265 Military Trail, Toronto M1C 1A4 (Canada); Goosey, Emma [Department of Earth Sciences, University of Toronto, 22 Russell Street, Toronto M5S 3B1 (Canada); Diamond, Miriam L., E-mail: miriam.diamond@utoronto.ca [Department of Earth Sciences, University of Toronto, 22 Russell Street, Toronto M5S 3B1 (Canada); Department of Physical and Environmental Sciences, University of Toronto, 1265 Military Trail, Toronto M1C 1A4 (Canada)

2016-03-01

Human exposure to halogenated flame retardants (HFRs) such as polybrominated diphenyl ethers (PBDEs) and their replacements, can be related to exposure to indoor dust and direct contact with HFR-containing products. This study aimed to identify electronic products that contributed to HFRs measured in indoor dust and to develop a screening method for identifying HFRs in hard polymer products. Concentrations of 10 PBDEs and 12 halogenated replacements in dust and surface wipe samples of hard polymer casings of electronic products plus Br in the surfaces of those casing measured using X-ray fluorescence (XRF) were analyzed from 35 homes and 10 offices in Toronto (ON, Canada). HFR concentrations in dust and product wipes were positively correlated. Thus, we hypothesize that electronic products with the highest HFR concentrations contribute the most to concentrations in dust, regardless of the volatility of the HFR. Abundant HFRs in dust and product wipes were PBDEs (BDE-47, 99, 100, 153, 154, 183, 209), TDCPP, DBDPE, EH-TBB and BEHTBP. Older CRT TVs had the highest concentration of BDE-209 of all products tested. This was followed by higher concentrations of HFRs in PCs, Audio/Video (A/V) devices, small household appliances (HHAs) and flat screen TVs. The removal of HFRs from polymer surfaces using wipes supports concerns that HFRs could be transferred from these surfaces to hands as a result of direct contact with HFR-containing products. Surface wipe testing shows promise for screening additive HFRs. In comparison, the Br-content obtained using a handheld XRF analyzer did not correspond to concentrations obtained from surface wipe testing. - Highlights: • Concentrations of flame retardants in dust correlated with product surface wipes • Most abundant FRs in electronics were PBDEs, TDCPP, DBDPE, EH-TBB and BEHTBP. • Descending order of FRs in CRTs, TVs, PCs, A-V devices, and small household appliances • Product wipe testing, but not XRF, useful for non

Product screening for sources of halogenated flame retardants in Canadian house and office dust

International Nuclear Information System (INIS)

Abbasi, Golnoush; Saini, Amandeep; Goosey, Emma; Diamond, Miriam L.

2016-01-01

Human exposure to halogenated flame retardants (HFRs) such as polybrominated diphenyl ethers (PBDEs) and their replacements, can be related to exposure to indoor dust and direct contact with HFR-containing products. This study aimed to identify electronic products that contributed to HFRs measured in indoor dust and to develop a screening method for identifying HFRs in hard polymer products. Concentrations of 10 PBDEs and 12 halogenated replacements in dust and surface wipe samples of hard polymer casings of electronic products plus Br in the surfaces of those casing measured using X-ray fluorescence (XRF) were analyzed from 35 homes and 10 offices in Toronto (ON, Canada). HFR concentrations in dust and product wipes were positively correlated. Thus, we hypothesize that electronic products with the highest HFR concentrations contribute the most to concentrations in dust, regardless of the volatility of the HFR. Abundant HFRs in dust and product wipes were PBDEs (BDE-47, 99, 100, 153, 154, 183, 209), TDCPP, DBDPE, EH-TBB and BEHTBP. Older CRT TVs had the highest concentration of BDE-209 of all products tested. This was followed by higher concentrations of HFRs in PCs, Audio/Video (A/V) devices, small household appliances (HHAs) and flat screen TVs. The removal of HFRs from polymer surfaces using wipes supports concerns that HFRs could be transferred from these surfaces to hands as a result of direct contact with HFR-containing products. Surface wipe testing shows promise for screening additive HFRs. In comparison, the Br-content obtained using a handheld XRF analyzer did not correspond to concentrations obtained from surface wipe testing. - Highlights: • Concentrations of flame retardants in dust correlated with product surface wipes • Most abundant FRs in electronics were PBDEs, TDCPP, DBDPE, EH-TBB and BEHTBP. • Descending order of FRs in CRTs, TVs, PCs, A-V devices, and small household appliances • Product wipe testing, but not XRF, useful for non

Wet-digestion of environmental sample using silver-mediated electrochemical method

International Nuclear Information System (INIS)

Kuwabara, Jun

2010-01-01

An application of silver-mediated electrochemical method to environmental samples as the effective digestion method for iodine analysis was tried. Usual digestion method for 129 I in many type of environmental sample is combustion method using quartz glass tube. Chemical yield of iodine on the combustion method reduce depending on the type of sample. The silver-mediated electrochemical method is expected to achieve very low loss of iodine. In this study, dried kombu (Laminaria) sample was tried to digest with electrochemical cell. At the case of 1g of sample, digestion was completed for about 24 hours under the electric condition of <10V and <2A. After the digestion, oxidized species of iodine was reduced to iodide by adding sodium sulfite. And then the precipitate of silver iodide was obtained. (author)

A flexible method for multi-level sample size determination

International Nuclear Information System (INIS)

Lu, Ming-Shih; Sanborn, J.B.; Teichmann, T.

1997-01-01

This paper gives a flexible method to determine sample sizes for both systematic and random error models (this pertains to sampling problems in nuclear safeguard questions). In addition, the method allows different attribute rejection limits. The new method could assist achieving a higher detection probability and enhance inspection effectiveness

DOE methods for evaluating environmental and waste management samples

Energy Technology Data Exchange (ETDEWEB)

Goheen, S.C.; McCulloch, M.; Thomas, B.L.; Riley, R.G.; Sklarew, D.S.; Mong, G.M.; Fadeff, S.K. [eds.

1994-10-01

DOE Methods for Evaluating Environmental and Waste Management Samples (DOE Methods) is a resource intended to support sampling and analytical activities for the evaluation of environmental and waste management samples from U.S. Department of Energy (DOE) sites. DOE Methods is the result of extensive cooperation from all DOE analytical laboratories. All of these laboratories have contributed key information and provided technical reviews as well as significant moral support leading to the success of this document. DOE Methods is designed to encompass methods for collecting representative samples and for determining the radioisotope activity and organic and inorganic composition of a sample. These determinations will aid in defining the type and breadth of contamination and thus determine the extent of environmental restoration or waste management actions needed, as defined by the DOE, the U.S. Environmental Protection Agency, or others. The development of DOE Methods is supported by the Analytical Services Division of DOE. Unique methods or methods consolidated from similar procedures in the DOE Procedures Database are selected for potential inclusion in this document. Initial selection is based largely on DOE needs and procedure applicability and completeness. Methods appearing in this document are one of two types, {open_quotes}Draft{close_quotes} or {open_quotes}Verified{close_quotes}. {open_quotes}Draft{close_quotes} methods that have been reviewed internally and show potential for eventual verification are included in this document, but they have not been reviewed externally, and their precision and bias may not be known. {open_quotes}Verified{close_quotes} methods in DOE Methods have been reviewed by volunteers from various DOE sites and private corporations. These methods have delineated measures of precision and accuracy.

DOE methods for evaluating environmental and waste management samples

International Nuclear Information System (INIS)

Goheen, S.C.; McCulloch, M.; Thomas, B.L.; Riley, R.G.; Sklarew, D.S.; Mong, G.M.; Fadeff, S.K.

1994-10-01

DOE Methods for Evaluating Environmental and Waste Management Samples (DOE Methods) is a resource intended to support sampling and analytical activities for the evaluation of environmental and waste management samples from U.S. Department of Energy (DOE) sites. DOE Methods is the result of extensive cooperation from all DOE analytical laboratories. All of these laboratories have contributed key information and provided technical reviews as well as significant moral support leading to the success of this document. DOE Methods is designed to encompass methods for collecting representative samples and for determining the radioisotope activity and organic and inorganic composition of a sample. These determinations will aid in defining the type and breadth of contamination and thus determine the extent of environmental restoration or waste management actions needed, as defined by the DOE, the U.S. Environmental Protection Agency, or others. The development of DOE Methods is supported by the Analytical Services Division of DOE. Unique methods or methods consolidated from similar procedures in the DOE Procedures Database are selected for potential inclusion in this document. Initial selection is based largely on DOE needs and procedure applicability and completeness. Methods appearing in this document are one of two types, open-quotes Draftclose quotes or open-quotes Verifiedclose quotes. open-quotes Draftclose quotes methods that have been reviewed internally and show potential for eventual verification are included in this document, but they have not been reviewed externally, and their precision and bias may not be known. open-quotes Verifiedclose quotes methods in DOE Methods have been reviewed by volunteers from various DOE sites and private corporations. These methods have delineated measures of precision and accuracy

Neutron activation analysis of certified samples by the absolute method

Science.gov (United States)

Kadem, F.; Belouadah, N.; Idiri, Z.

2015-07-01

The nuclear reactions analysis technique is mainly based on the relative method or the use of activation cross sections. In order to validate nuclear data for the calculated cross section evaluated from systematic studies, we used the neutron activation analysis technique (NAA) to determine the various constituent concentrations of certified samples for animal blood, milk and hay. In this analysis, the absolute method is used. The neutron activation technique involves irradiating the sample and subsequently performing a measurement of the activity of the sample. The fundamental equation of the activation connects several physical parameters including the cross section that is essential for the quantitative determination of the different elements composing the sample without resorting to the use of standard sample. Called the absolute method, it allows a measurement as accurate as the relative method. The results obtained by the absolute method showed that the values are as precise as the relative method requiring the use of standard sample for each element to be quantified.

THE USE OF RANKING SAMPLING METHOD WITHIN MARKETING RESEARCH

Directory of Open Access Journals (Sweden)

CODRUŢA DURA

2011-01-01

Full Text Available Marketing and statistical literature available to practitioners provides a wide range of sampling methods that can be implemented in the context of marketing research. Ranking sampling method is based on taking apart the general population into several strata, namely into several subdivisions which are relatively homogenous regarding a certain characteristic. In fact, the sample will be composed by selecting, from each stratum, a certain number of components (which can be proportional or non-proportional to the size of the stratum until the pre-established volume of the sample is reached. Using ranking sampling within marketing research requires the determination of some relevant statistical indicators - average, dispersion, sampling error etc. To that end, the paper contains a case study which illustrates the actual approach used in order to apply the ranking sample method within a marketing research made by a company which provides Internet connection services, on a particular category of customers – small and medium enterprises.

Validation of single-sample doubly labeled water method

International Nuclear Information System (INIS)

Webster, M.D.; Weathers, W.W.

1989-01-01

We have experimentally validated a single-sample variant of the doubly labeled water method for measuring metabolic rate and water turnover in a very small passerine bird, the verdin (Auriparus flaviceps). We measured CO 2 production using the Haldane gravimetric technique and compared these values with estimates derived from isotopic data. Doubly labeled water results based on the one-sample calculations differed from Haldane values by less than 0.5% on average (range -8.3 to 11.2%, n = 9). Water flux computed by the single-sample method differed by -1.5% on average from results for the same birds based on the standard, two-sample technique (range -13.7 to 2.0%, n = 9)

Sample Size Calculations for Population Size Estimation Studies Using Multiplier Methods With Respondent-Driven Sampling Surveys.

Science.gov (United States)

Fearon, Elizabeth; Chabata, Sungai T; Thompson, Jennifer A; Cowan, Frances M; Hargreaves, James R

2017-09-14

While guidance exists for obtaining population size estimates using multiplier methods with respondent-driven sampling surveys, we lack specific guidance for making sample size decisions. To guide the design of multiplier method population size estimation studies using respondent-driven sampling surveys to reduce the random error around the estimate obtained. The population size estimate is obtained by dividing the number of individuals receiving a service or the number of unique objects distributed (M) by the proportion of individuals in a representative survey who report receipt of the service or object (P). We have developed an approach to sample size calculation, interpreting methods to estimate the variance around estimates obtained using multiplier methods in conjunction with research into design effects and respondent-driven sampling. We describe an application to estimate the number of female sex workers in Harare, Zimbabwe. There is high variance in estimates. Random error around the size estimate reflects uncertainty from M and P, particularly when the estimate of P in the respondent-driven sampling survey is low. As expected, sample size requirements are higher when the design effect of the survey is assumed to be greater. We suggest a method for investigating the effects of sample size on the precision of a population size estimate obtained using multipler methods and respondent-driven sampling. Uncertainty in the size estimate is high, particularly when P is small, so balancing against other potential sources of bias, we advise researchers to consider longer service attendance reference periods and to distribute more unique objects, which is likely to result in a higher estimate of P in the respondent-driven sampling survey. ©Elizabeth Fearon, Sungai T Chabata, Jennifer A Thompson, Frances M Cowan, James R Hargreaves. Originally published in JMIR Public Health and Surveillance (http://publichealth.jmir.org), 14.09.2017.

Standard methods for sampling North American freshwater fishes

Science.gov (United States)

Bonar, Scott A.; Hubert, Wayne A.; Willis, David W.

2009-01-01

This important reference book provides standard sampling methods recommended by the American Fisheries Society for assessing and monitoring freshwater fish populations in North America. Methods apply to ponds, reservoirs, natural lakes, and streams and rivers containing cold and warmwater fishes. Range-wide and eco-regional averages for indices of abundance, population structure, and condition for individual species are supplied to facilitate comparisons of standard data among populations. Provides information on converting nonstandard to standard data, statistical and database procedures for analyzing and storing standard data, and methods to prevent transfer of invasive species while sampling.

Passive sampling methods for contaminated sediments

DEFF Research Database (Denmark)

Peijnenburg, Willie J.G.M.; Teasdale, Peter R.; Reible, Danny

2014-01-01

“Dissolved” concentrations of contaminants in sediment porewater (Cfree) provide a more relevant exposure metric for risk assessment than do total concentrations. Passive sampling methods (PSMs) for estimating Cfree offer the potential for cost-efficient and accurate in situ characterization...

Field evaluation of personal sampling methods for multiple bioaerosols.

Science.gov (United States)

Wang, Chi-Hsun; Chen, Bean T; Han, Bor-Cheng; Liu, Andrew Chi-Yeu; Hung, Po-Chen; Chen, Chih-Yong; Chao, Hsing Jasmine

2015-01-01

Ambient bioaerosols are ubiquitous in the daily environment and can affect health in various ways. However, few studies have been conducted to comprehensively evaluate personal bioaerosol exposure in occupational and indoor environments because of the complex composition of bioaerosols and the lack of standardized sampling/analysis methods. We conducted a study to determine the most efficient collection/analysis method for the personal exposure assessment of multiple bioaerosols. The sampling efficiencies of three filters and four samplers were compared. According to our results, polycarbonate (PC) filters had the highest relative efficiency, particularly for bacteria. Side-by-side sampling was conducted to evaluate the three filter samplers (with PC filters) and the NIOSH Personal Bioaerosol Cyclone Sampler. According to the results, the Button Aerosol Sampler and the IOM Inhalable Dust Sampler had the highest relative efficiencies for fungi and bacteria, followed by the NIOSH sampler. Personal sampling was performed in a pig farm to assess occupational bioaerosol exposure and to evaluate the sampling/analysis methods. The Button and IOM samplers yielded a similar performance for personal bioaerosol sampling at the pig farm. However, the Button sampler is more likely to be clogged at high airborne dust concentrations because of its higher flow rate (4 L/min). Therefore, the IOM sampler is a more appropriate choice for performing personal sampling in environments with high dust levels. In summary, the Button and IOM samplers with PC filters are efficient sampling/analysis methods for the personal exposure assessment of multiple bioaerosols.

[Sampling methods for PM2.5 from stationary sources: a review].

Science.gov (United States)

Jiang, Jing-Kun; Deng, Jian-Guo; Li, Zhen; Li, Xing-Hua; Duan, Lei; Hao, Ji-Ming

2014-05-01

The new China national ambient air quality standard has been published in 2012 and will be implemented in 2016. To meet the requirements in this new standard, monitoring and controlling PM2,,5 emission from stationary sources are very important. However, so far there is no national standard method on sampling PM2.5 from stationary sources. Different sampling methods for PM2.5 from stationary sources and relevant international standards were reviewed in this study. It includes the methods for PM2.5 sampling in flue gas and the methods for PM2.5 sampling after dilution. Both advantages and disadvantages of these sampling methods were discussed. For environmental management, the method for PM2.5 sampling in flue gas such as impactor and virtual impactor was suggested as a standard to determine filterable PM2.5. To evaluate environmental and health effects of PM2.5 from stationary sources, standard dilution method for sampling of total PM2.5 should be established.

Sampling strategy for estimating human exposure pathways to consumer chemicals

Directory of Open Access Journals (Sweden)

Eleni Papadopoulou

2016-03-01

Full Text Available Human exposure to consumer chemicals has become a worldwide concern. In this work, a comprehensive sampling strategy is presented, to our knowledge being the first to study all relevant exposure pathways in a single cohort using multiple methods for assessment of exposure from each exposure pathway. The selected groups of chemicals to be studied are consumer chemicals whose production and use are currently in a state of transition and are; per- and polyfluorinated alkyl substances (PFASs, traditional and “emerging” brominated flame retardants (BFRs and EBFRs, organophosphate esters (OPEs and phthalate esters (PEs. Information about human exposure to these contaminants is needed due to existing data gaps on human exposure intakes from multiple exposure pathways and relationships between internal and external exposure. Indoor environment, food and biological samples were collected from 61 participants and their households in the Oslo area (Norway on two consecutive days, during winter 2013-14. Air, dust, hand wipes, and duplicate diet (food and drink samples were collected as indicators of external exposure, and blood, urine, blood spots, hair, nails and saliva as indicators of internal exposure. A food diary, food frequency questionnaire (FFQ and indoor environment questionnaire were also implemented. Approximately 2000 samples were collected in total and participant views on their experiences of this campaign were collected via questionnaire. While 91% of our participants were positive about future participation in a similar project, some tasks were viewed as problematic. Completing the food diary and collection of duplicate food/drink portions were the tasks most frequent reported as “hard”/”very hard”. Nevertheless, a strong positive correlation between the reported total mass of food/drinks in the food record and the total weight of the food/drinks in the collection bottles was observed, being an indication of accurate performance

Approximation of the exponential integral (well function) using sampling methods

Science.gov (United States)

Baalousha, Husam Musa

2015-04-01

Exponential integral (also known as well function) is often used in hydrogeology to solve Theis and Hantush equations. Many methods have been developed to approximate the exponential integral. Most of these methods are based on numerical approximations and are valid for a certain range of the argument value. This paper presents a new approach to approximate the exponential integral. The new approach is based on sampling methods. Three different sampling methods; Latin Hypercube Sampling (LHS), Orthogonal Array (OA), and Orthogonal Array-based Latin Hypercube (OA-LH) have been used to approximate the function. Different argument values, covering a wide range, have been used. The results of sampling methods were compared with results obtained by Mathematica software, which was used as a benchmark. All three sampling methods converge to the result obtained by Mathematica, at different rates. It was found that the orthogonal array (OA) method has the fastest convergence rate compared with LHS and OA-LH. The root mean square error RMSE of OA was in the order of 1E-08. This method can be used with any argument value, and can be used to solve other integrals in hydrogeology such as the leaky aquifer integral.

40 CFR 80.8 - Sampling methods for gasoline and diesel fuel.

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 16 2010-07-01 2010-07-01 false Sampling methods for gasoline and... PROGRAMS (CONTINUED) REGULATION OF FUELS AND FUEL ADDITIVES General Provisions § 80.8 Sampling methods for gasoline and diesel fuel. The sampling methods specified in this section shall be used to collect samples...

Characterization of hazardous waste sites: a methods manual. Volume 2. Available sampling methods (second edition)

International Nuclear Information System (INIS)

Ford, P.J.; Turina, P.J.; Seely, D.E.

1984-12-01

Investigations at hazardous waste sites and sites of chemical spills often require on-site measurements and sampling activities to assess the type and extent of contamination. This document is a compilation of sampling methods and materials suitable to address most needs that arise during routine waste site and hazardous spill investigations. The sampling methods presented in this document are compiled by media, and were selected on the basis of practicality, economics, representativeness, compatability with analytical considerations, and safety, as well as other criteria. In addition to sampling procedures, sample handling and shipping, chain-of-custody procedures, instrument certification, equipment fabrication, and equipment decontamination procedures are described. Sampling methods for soil, sludges, sediments, and bulk materials cover the solids medium. Ten methods are detailed for surface waters, groundwater and containerized liquids; twelve are presented for ambient air, soil gases and vapors, and headspace gases. A brief discussion of ionizing radiation survey instruments is also provided

Adaptive sampling method in deep-penetration particle transport problem

International Nuclear Information System (INIS)

Wang Ruihong; Ji Zhicheng; Pei Lucheng

2012-01-01

Deep-penetration problem has been one of the difficult problems in shielding calculation with Monte Carlo method for several decades. In this paper, a kind of particle transport random walking system under the emission point as a sampling station is built. Then, an adaptive sampling scheme is derived for better solution with the achieved information. The main advantage of the adaptive scheme is to choose the most suitable sampling number from the emission point station to obtain the minimum value of the total cost in the process of the random walk. Further, the related importance sampling method is introduced. Its main principle is to define the importance function due to the particle state and to ensure the sampling number of the emission particle is proportional to the importance function. The numerical results show that the adaptive scheme under the emission point as a station could overcome the difficulty of underestimation of the result in some degree, and the adaptive importance sampling method gets satisfied results as well. (authors)

Field evaluation of personal sampling methods for multiple bioaerosols.

Directory of Open Access Journals (Sweden)

Chi-Hsun Wang

Full Text Available Ambient bioaerosols are ubiquitous in the daily environment and can affect health in various ways. However, few studies have been conducted to comprehensively evaluate personal bioaerosol exposure in occupational and indoor environments because of the complex composition of bioaerosols and the lack of standardized sampling/analysis methods. We conducted a study to determine the most efficient collection/analysis method for the personal exposure assessment of multiple bioaerosols. The sampling efficiencies of three filters and four samplers were compared. According to our results, polycarbonate (PC filters had the highest relative efficiency, particularly for bacteria. Side-by-side sampling was conducted to evaluate the three filter samplers (with PC filters and the NIOSH Personal Bioaerosol Cyclone Sampler. According to the results, the Button Aerosol Sampler and the IOM Inhalable Dust Sampler had the highest relative efficiencies for fungi and bacteria, followed by the NIOSH sampler. Personal sampling was performed in a pig farm to assess occupational bioaerosol exposure and to evaluate the sampling/analysis methods. The Button and IOM samplers yielded a similar performance for personal bioaerosol sampling at the pig farm. However, the Button sampler is more likely to be clogged at high airborne dust concentrations because of its higher flow rate (4 L/min. Therefore, the IOM sampler is a more appropriate choice for performing personal sampling in environments with high dust levels. In summary, the Button and IOM samplers with PC filters are efficient sampling/analysis methods for the personal exposure assessment of multiple bioaerosols.

Sample preparation method for ICP-MS measurement of 99Tc in a large amount of environmental samples

International Nuclear Information System (INIS)

Kondo, M.; Seki, R.

2002-01-01

Sample preparation for measurement of 99 Tc in a large amount of soil and water samples by ICP-MS has been developed using 95m Tc as a yield tracer. This method is based on the conventional method for a small amount of soil samples using incineration, acid digestion, extraction chromatography (TEVA resin) and ICP-MS measurement. Preliminary concentration of Tc has been introduced by co-precipitation with ferric oxide. The matrix materials in a large amount of samples were more sufficiently removed with keeping the high recovery of Tc than previous method. The recovery of Tc was 70-80% for 100 g soil samples and 60-70% for 500 g of soil and 500 L of water samples. The detection limit of this method was evaluated as 0.054 mBq/kg in 500 g soil and 0.032 μBq/L in 500 L water. The determined value of 99 Tc in the IAEA-375 (soil sample collected near the Chernobyl Nuclear Reactor) was 0.25 ± 0.02 Bq/kg. (author)

Systems and methods for self-synchronized digital sampling

Science.gov (United States)

Samson, Jr., John R. (Inventor)

2008-01-01

Systems and methods for self-synchronized data sampling are provided. In one embodiment, a system for capturing synchronous data samples is provided. The system includes an analog to digital converter adapted to capture signals from one or more sensors and convert the signals into a stream of digital data samples at a sampling frequency determined by a sampling control signal; and a synchronizer coupled to the analog to digital converter and adapted to receive a rotational frequency signal from a rotating machine, wherein the synchronizer is further adapted to generate the sampling control signal, and wherein the sampling control signal is based on the rotational frequency signal.

Method for removal of beryllium contamination from an article

Science.gov (United States)

Simandl, Ronald F.; Hollenbeck, Scott M.

2012-12-25

A method of removal of beryllium contamination from an article is disclosed. The method typically involves dissolving polyisobutylene in a solvent such as hexane to form a tackifier solution, soaking the substrate in the tackifier to produce a preform, and then drying the preform to produce the cleaning medium. The cleaning media are typically used dry, without any liquid cleaning agent to rub the surface of the article and remove the beryllium contamination below a non-detect level. In some embodiments no detectible residue is transferred from the cleaning wipe to the article as a result of the cleaning process.

Method and apparatus for sampling atmospheric mercury

Science.gov (United States)

Trujillo, Patricio E.; Campbell, Evan E.; Eutsler, Bernard C.

1976-01-20

A method of simultaneously sampling particulate mercury, organic mercurial vapors, and metallic mercury vapor in the working and occupational environment and determining the amount of mercury derived from each such source in the sampled air. A known volume of air is passed through a sampling tube containing a filter for particulate mercury collection, a first adsorber for the selective adsorption of organic mercurial vapors, and a second adsorber for the adsorption of metallic mercury vapor. Carbon black molecular sieves are particularly useful as the selective adsorber for organic mercurial vapors. The amount of mercury adsorbed or collected in each section of the sampling tube is readily quantitatively determined by flameless atomic absorption spectrophotometry.

A Sequential Optimization Sampling Method for Metamodels with Radial Basis Functions

Science.gov (United States)

Pan, Guang; Ye, Pengcheng; Yang, Zhidong

2014-01-01

Metamodels have been widely used in engineering design to facilitate analysis and optimization of complex systems that involve computationally expensive simulation programs. The accuracy of metamodels is strongly affected by the sampling methods. In this paper, a new sequential optimization sampling method is proposed. Based on the new sampling method, metamodels can be constructed repeatedly through the addition of sampling points, namely, extrema points of metamodels and minimum points of density function. Afterwards, the more accurate metamodels would be constructed by the procedure above. The validity and effectiveness of proposed sampling method are examined by studying typical numerical examples. PMID:25133206

Characterizing lentic freshwater fish assemblages using multiple sampling methods

Science.gov (United States)

Fischer, Jesse R.; Quist, Michael C.

2014-01-01

Characterizing fish assemblages in lentic ecosystems is difficult, and multiple sampling methods are almost always necessary to gain reliable estimates of indices such as species richness. However, most research focused on lentic fish sampling methodology has targeted recreationally important species, and little to no information is available regarding the influence of multiple methods and timing (i.e., temporal variation) on characterizing entire fish assemblages. Therefore, six lakes and impoundments (48–1,557 ha surface area) were sampled seasonally with seven gear types to evaluate the combined influence of sampling methods and timing on the number of species and individuals sampled. Probabilities of detection for species indicated strong selectivities and seasonal trends that provide guidance on optimal seasons to use gears when targeting multiple species. The evaluation of species richness and number of individuals sampled using multiple gear combinations demonstrated that appreciable benefits over relatively few gears (e.g., to four) used in optimal seasons were not present. Specifically, over 90 % of the species encountered with all gear types and season combinations (N = 19) from six lakes and reservoirs were sampled with nighttime boat electrofishing in the fall and benthic trawling, modified-fyke, and mini-fyke netting during the summer. Our results indicated that the characterization of lentic fish assemblages was highly influenced by the selection of sampling gears and seasons, but did not appear to be influenced by waterbody type (i.e., natural lake, impoundment). The standardization of data collected with multiple methods and seasons to account for bias is imperative to monitoring of lentic ecosystems and will provide researchers with increased reliability in their interpretations and decisions made using information on lentic fish assemblages.

Optical methods for microstructure determination of doped samples

Science.gov (United States)

Ciosek, Jerzy F.

2008-12-01

The optical methods to determine refractive index profile of layered materials are commonly used with spectroscopic ellipsometry or transmittance/reflectance spectrometry. Measurements of spectral reflection and transmission usually permit to characterize optical materials and determine their refractive index. However, it is possible to characterize of samples with dopants, impurities as well as defects using optical methods. Microstructures of a hydrogenated crystalline Si wafer and a layer of SiO2 - ZrO2 composition are investigated. The first sample is a Si(001):H Czochralski grown single crystalline wafer with 50 nm thick surface Si02 layer. Hydrogen dose implantation (D continue to be an important issue in microelectronic device and sensor fabrication. Hydrogen-implanted silicon (Si: H) has become a topic of remarkable interest, mostly because of the potential of implantation-induced platelets and micro-cavities for the creation of gettering -active areas and for Si layer splitting. Oxygen precipitation and atmospheric impurity are analysed. The second sample is the layer of co-evaporated SiO2 and ZrO2 materials using simultaneously two electron beam guns in reactive evaporation methods. The composition structure was investigated by X-Ray photoelectron spectroscopy (XPS), and spectroscopic ellipsometry methods. A non-uniformity and composition of layer are analysed using average density method.

Evaluation of sampling methods for Bacillus spore-contaminated HVAC filters.

Science.gov (United States)

Calfee, M Worth; Rose, Laura J; Tufts, Jenia; Morse, Stephen; Clayton, Matt; Touati, Abderrahmane; Griffin-Gatchalian, Nicole; Slone, Christina; McSweeney, Neal

2014-01-01

The objective of this study was to compare an extraction-based sampling method to two vacuum-based sampling methods (vacuum sock and 37mm cassette filter) with regards to their ability to recover Bacillus atrophaeus spores (surrogate for Bacillus anthracis) from pleated heating, ventilation, and air conditioning (HVAC) filters that are typically found in commercial and residential buildings. Electrostatic and mechanical HVAC filters were tested, both without and after loading with dust to 50% of their total holding capacity. The results were analyzed by one-way ANOVA across material types, presence or absence of dust, and sampling device. The extraction method gave higher relative recoveries than the two vacuum methods evaluated (p≤0.001). On average, recoveries obtained by the vacuum methods were about 30% of those achieved by the extraction method. Relative recoveries between the two vacuum methods were not significantly different (p>0.05). Although extraction methods yielded higher recoveries than vacuum methods, either HVAC filter sampling approach may provide a rapid and inexpensive mechanism for understanding the extent of contamination following a wide-area biological release incident. Published by Elsevier B.V.

Field Sample Preparation Method Development for Isotope Ratio Mass Spectrometry

International Nuclear Information System (INIS)

Leibman, C.; Weisbrod, K.; Yoshida, T.

2015-01-01

Non-proliferation and International Security (NA-241) established a working group of researchers from Los Alamos National Laboratory (LANL), Pacific Northwest National Laboratory (PNNL) and Savannah River National Laboratory (SRNL) to evaluate the utilization of in-field mass spectrometry for safeguards applications. The survey of commercial off-the-shelf (COTS) mass spectrometers (MS) revealed no instrumentation existed capable of meeting all the potential safeguards requirements for performance, portability, and ease of use. Additionally, fieldable instruments are unlikely to meet the International Target Values (ITVs) for accuracy and precision for isotope ratio measurements achieved with laboratory methods. The major gaps identified for in-field actinide isotope ratio analysis were in the areas of: 1. sample preparation and/or sample introduction, 2. size reduction of mass analyzers and ionization sources, 3. system automation, and 4. decreased system cost. Development work in 2 through 4, numerated above continues, in the private and public sector. LANL is focusing on developing sample preparation/sample introduction methods for use with the different sample types anticipated for safeguard applications. Addressing sample handling and sample preparation methods for MS analysis will enable use of new MS instrumentation as it becomes commercially available. As one example, we have developed a rapid, sample preparation method for dissolution of uranium and plutonium oxides using ammonium bifluoride (ABF). ABF is a significantly safer and faster alternative to digestion with boiling combinations of highly concentrated mineral acids. Actinides digested with ABF yield fluorides, which can then be analyzed directly or chemically converted and separated using established column chromatography techniques as needed prior to isotope analysis. The reagent volumes and the sample processing steps associated with ABF sample digestion lend themselves to automation and field

Radiochemistry methods in DOE methods for evaluating environmental and waste management samples

International Nuclear Information System (INIS)

Fadeff, S.K.; Goheen, S.C.

1994-08-01

Current standard sources of radiochemistry methods are often inappropriate for use in evaluating US Department of Energy environmental and waste management (DOE/EW) samples. Examples of current sources include EPA, ASTM, Standard Methods for the Examination of Water and Wastewater and HASL-300. Applicability of these methods is limited to specific matrices (usually water), radiation levels (usually environmental levels), and analytes (limited number). Radiochemistry methods in DOE Methods for Evaluating Environmental and Waste Management Samples (DOE Methods) attempt to fill the applicability gap that exists between standard methods and those needed for DOE/EM activities. The Radiochemistry chapter in DOE Methods includes an ''analysis and reporting'' guidance section as well as radiochemistry methods. A basis for identifying the DOE/EM radiochemistry needs is discussed. Within this needs framework, the applicability of standard methods and targeted new methods is identified. Sources of new methods (consolidated methods from DOE laboratories and submissions from individuals) and the methods review process will be discussed. The processes involved in generating consolidated methods add editing individually submitted methods will be compared. DOE Methods is a living document and continues to expand by adding various kinds of methods. Radiochemistry methods are highlighted in this paper. DOE Methods is intended to be a resource for methods applicable to DOE/EM problems. Although it is intended to support DOE, the guidance and methods are not necessarily exclusive to DOE. The document is available at no cost through the Laboratory Management Division of DOE, Office of Technology Development

7 CFR 51.308 - Methods of sampling and calculation of percentages.

Science.gov (United States)

2010-01-01

..., CERTIFICATION, AND STANDARDS) United States Standards for Grades of Apples Methods of Sampling and Calculation of Percentages § 51.308 Methods of sampling and calculation of percentages. (a) When the numerical... 7 Agriculture 2 2010-01-01 2010-01-01 false Methods of sampling and calculation of percentages. 51...

Dissemination of Pathogens by Mobile Phones in a Single Hospital

Directory of Open Access Journals (Sweden)

Michael B Canales, DPM, FACFAS

2017-10-01

Full Text Available Background: Superficial wound complications are among the most prevalent problems associated with any surgical procedures.  Infection rates of the primary hip and knee joint arthroplasty have been reduced with modern aseptic techniques but this rate may reach 20% in some revision procedures.  Mobile phones are frequently used in the hospital and operating room settings, regardless of their microbial load.    This study aimed to: 1 determine the level of bacterial contamination of mobile phones from resident physicians at Saint Vincent Charity Medical Center (SVCMC in Cleveland, Ohio; 2 determine the effectiveness of quaternary ammonium compound (QAC wipes; and 3 heighten awareness of potential dissemination of pathogens by mobile phones in the hospital setting. Materials & Methods: A total of fifty mobile phones were randomly sampled from podiatric surgical resident physicians and internal medicine resident physicians at SVCMC. For each mobile phone, a swab was collected from the touch screen prior to use of QAC wipes and following use of QAC wipes. Results: The results demonstrated that 82% (41/50 of mobile phone touch screens possessed polymicrobial organisms and 30% (15/50 of mobile phones possessed pathogenic organisms.  The vast majority of residents, 98% (49/50 used their phones within the hospital and 37% (18/49 used their phones inside patients’ room. Most of the residents, 86% (43/50, did not clean their phones on a daily basis and of the residents who did, a majority of them, 71% (5/7 used either dry wipes or alcohol wipes. Discussion: Sanitizing mobile phones with QAC disposable wipes was shown to be an effective infection control intervention as mobile phone touch screens showed no growth after two minutes of sanitization.  QAC could potentially decrease the transmission of microorganisms that cause diseases and reduce the risk of cross contamination infections from mobile phones.

Sanitizer efficacy against murine norovirus, a surrogate for human norovirus, on stainless steel surfaces when using three application methods.

Science.gov (United States)

Bolton, Stephanie L; Kotwal, Grishma; Harrison, Mark A; Law, S Edward; Harrison, Judy A; Cannon, Jennifer L

2013-02-01

Human noroviruses are major etiologic agents of epidemic gastroenteritis. Outbreaks are often accompanied by contamination of environmental surfaces, but since these viruses cannot be routinely propagated in laboratory cultures, their response to surface disinfectants is predicted by using surrogates, such as murine norovirus 1 (MNV-1). This study compared the virucidal efficacies of various liquid treatments (three sanitizer liquids, 5% levulinic acid plus 2% SDS [LEV/SDS], 200 ppm chlorine, and an isopropanol-based quaternary ammonium compound [Alpet D2], and two control liquids, sterile tap water and sterile tap water plus 2% SDS) when delivered to MNV-1-inoculated stainless steel surfaces by conventional hydraulic or air-assisted, induction-charged (AAIC) electrostatic spraying or by wiping with impregnated towelettes. For the spray treatments, LEV/SDS proved effective when applied with hydraulic and AAIC electrostatic spraying, providing virus reductions of 2.71 and 1.66 log PFU/ml, respectively. Alpet D2 provided a 2.23-log PFU/ml reduction with hydraulic spraying, outperforming chlorine (1.16-log PFU/ml reduction). Chlorine and LEV/SDS were equally effective as wipes, reducing the viral load by 7.05 log PFU/ml. Controls reduced the viral load by 3 log PFU/ml with wiping. Results indicated that both sanitizer type and application methods should be carefully considered when choosing a surface disinfectant to best prevent and control environmental contamination by noroviruses.

Sampling trace organic compounds in water: a comparison of a continuous active sampler to continuous passive and discrete sampling methods.

Science.gov (United States)

Coes, Alissa L; Paretti, Nicholas V; Foreman, William T; Iverson, Jana L; Alvarez, David A

2014-03-01

A continuous active sampling method was compared to continuous passive and discrete sampling methods for the sampling of trace organic compounds (TOCs) in water. Results from each method are compared and contrasted in order to provide information for future investigators to use while selecting appropriate sampling methods for their research. The continuous low-level aquatic monitoring (CLAM) sampler (C.I.Agent® Storm-Water Solutions) is a submersible, low flow-rate sampler, that continuously draws water through solid-phase extraction media. CLAM samplers were deployed at two wastewater-dominated stream field sites in conjunction with the deployment of polar organic chemical integrative samplers (POCIS) and the collection of discrete (grab) water samples. All samples were analyzed for a suite of 69 TOCs. The CLAM and POCIS samples represent time-integrated samples that accumulate the TOCs present in the water over the deployment period (19-23 h for CLAM and 29 days for POCIS); the discrete samples represent only the TOCs present in the water at the time and place of sampling. Non-metric multi-dimensional scaling and cluster analysis were used to examine patterns in both TOC detections and relative concentrations between the three sampling methods. A greater number of TOCs were detected in the CLAM samples than in corresponding discrete and POCIS samples, but TOC concentrations in the CLAM samples were significantly lower than in the discrete and (or) POCIS samples. Thirteen TOCs of varying polarity were detected by all of the three methods. TOC detections and concentrations obtained by the three sampling methods, however, are dependent on multiple factors. This study found that stream discharge, constituent loading, and compound type all affected TOC concentrations detected by each method. In addition, TOC detections and concentrations were affected by the reporting limits, bias, recovery, and performance of each method. Published by Elsevier B.V.

Sampling trace organic compounds in water: a comparison of a continuous active sampler to continuous passive and discrete sampling methods

Science.gov (United States)

Coes, Alissa L.; Paretti, Nicholas V.; Foreman, William T.; Iverson, Jana L.; Alvarez, David A.

2014-01-01

A continuous active sampling method was compared to continuous passive and discrete sampling methods for the sampling of trace organic compounds (TOCs) in water. Results from each method are compared and contrasted in order to provide information for future investigators to use while selecting appropriate sampling methods for their research. The continuous low-level aquatic monitoring (CLAM) sampler (C.I.Agent® Storm-Water Solutions) is a submersible, low flow-rate sampler, that continuously draws water through solid-phase extraction media. CLAM samplers were deployed at two wastewater-dominated stream field sites in conjunction with the deployment of polar organic chemical integrative samplers (POCIS) and the collection of discrete (grab) water samples. All samples were analyzed for a suite of 69 TOCs. The CLAM and POCIS samples represent time-integrated samples that accumulate the TOCs present in the water over the deployment period (19–23 h for CLAM and 29 days for POCIS); the discrete samples represent only the TOCs present in the water at the time and place of sampling. Non-metric multi-dimensional scaling and cluster analysis were used to examine patterns in both TOC detections and relative concentrations between the three sampling methods. A greater number of TOCs were detected in the CLAM samples than in corresponding discrete and POCIS samples, but TOC concentrations in the CLAM samples were significantly lower than in the discrete and (or) POCIS samples. Thirteen TOCs of varying polarity were detected by all of the three methods. TOC detections and concentrations obtained by the three sampling methods, however, are dependent on multiple factors. This study found that stream discharge, constituent loading, and compound type all affected TOC concentrations detected by each method. In addition, TOC detections and concentrations were affected by the reporting limits, bias, recovery, and performance of each method.

Multi-frequency direct sampling method in inverse scattering problem

Science.gov (United States)

Kang, Sangwoo; Lambert, Marc; Park, Won-Kwang

2017-10-01

We consider the direct sampling method (DSM) for the two-dimensional inverse scattering problem. Although DSM is fast, stable, and effective, some phenomena remain unexplained by the existing results. We show that the imaging function of the direct sampling method can be expressed by a Bessel function of order zero. We also clarify the previously unexplained imaging phenomena and suggest multi-frequency DSM to overcome traditional DSM. Our method is evaluated in simulation studies using both single and multiple frequencies.

Influences of different sample preparation methods on tooth enamel ESR signals

International Nuclear Information System (INIS)

Zhang Wenyi; Jiao Ling; Zhang Liang'an; Pan Zhihong; Zeng Hongyu

2005-01-01

Objective: To study the influences of different sample preparation methods on tooth enamel ESR signals in order to reduce the effect of dentine on their sensitivities to radiation. Methods: The enamel was separated from dentine of non-irradiated adult teeth by mechanical, chemical, or both methods. The samples of different preparations were scanned by an ESR spectrometer before and after irradiation. Results: The response of ESR signals of samples prepared with different methods to radiation dose was significantly different. Conclusion: The selection of sample preparation method is very important for dose reconstruction by tooth enamel ESR dosimetry, especially in the low dose range. (authors)

Experimental analysis on removal factor of smear method in measurement of surface contamination

International Nuclear Information System (INIS)

Sugiura, Nobuyuki; Taira, Junichi; Takenaka, Keisuke; Yamanaka, Kazuo; Sugai, Kenji; Kosako, Toshiso

2007-01-01

The smear test is one of the important ways to measure surface contamination. The loose contamination under the high background radiation, which is more significant in handling non-sealed radioisotopes, can be evaluated by this method. The removal factor is defined as the ratio of the activity removed from the surface by one smear to the whole activity of the removable surface contamination. The removal factor is greatly changed by the quality and condition of surface materials. In this study, the values of removal factor at several typical surface conditions were evaluated experimentally and the practical application of those values was considered. It is required the smear should be pressed by moderate pressure when wiping the surface. The pressure from 1.0 kg to 1.5 kg per filter paper was recommended. The removal factor showed lower value in wiping by the pressure below 1.0 kg. The value of 0.5 for the removal factor could be applied to the smooth surface of linoleum, concrete coated with paint or epoxy resin, stainless steel and glass with the statistical allowance. (author)

Methods for Sampling and Measurement of Compressed Air Contaminants

Energy Technology Data Exchange (ETDEWEB)

Stroem, L

1976-10-15

In order to improve the technique for measuring oil and water entrained in a compressed air stream, a laboratory study has been made of some methods for sampling and measurement. For this purpose water or oil as artificial contaminants were injected in thin streams into a test loop, carrying dry compressed air. Sampling was performed in a vertical run, down-stream of the injection point. Wall attached liquid, coarse droplet flow, and fine droplet flow were sampled separately. The results were compared with two-phase flow theory and direct observation of liquid behaviour. In a study of sample transport through narrow tubes, it was observed that, below a certain liquid loading, the sample did not move, the liquid remaining stationary on the tubing wall. The basic analysis of the collected samples was made by gravimetric methods. Adsorption tubes were used with success to measure water vapour. A humidity meter with a sensor of the aluminium oxide type was found to be unreliable. Oil could be measured selectively by a flame ionization detector, the sample being pretreated in an evaporation- condensation unit

Methods for Sampling and Measurement of Compressed Air Contaminants

International Nuclear Information System (INIS)

Stroem, L.

1976-10-01

In order to improve the technique for measuring oil and water entrained in a compressed air stream, a laboratory study has been made of some methods for sampling and measurement. For this purpose water or oil as artificial contaminants were injected in thin streams into a test loop, carrying dry compressed air. Sampling was performed in a vertical run, down-stream of the injection point. Wall attached liquid, coarse droplet flow, and fine droplet flow were sampled separately. The results were compared with two-phase flow theory and direct observation of liquid behaviour. In a study of sample transport through narrow tubes, it was observed that, below a certain liquid loading, the sample did not move, the liquid remaining stationary on the tubing wall. The basic analysis of the collected samples was made by gravimetric methods. Adsorption tubes were used with success to measure water vapour. A humidity meter with a sensor of the aluminium oxide type was found to be unreliable. Oil could be measured selectively by a flame ionization detector, the sample being pretreated in an evaporation- condensation unit

Examination of Hydrate Formation Methods: Trying to Create Representative Samples

Energy Technology Data Exchange (ETDEWEB)

Kneafsey, T.J.; Rees, E.V.L.; Nakagawa, S.; Kwon, T.-H.

2011-04-01

Forming representative gas hydrate-bearing laboratory samples is important so that the properties of these materials may be measured, while controlling the composition and other variables. Natural samples are rare, and have often experienced pressure and temperature changes that may affect the property to be measured [Waite et al., 2008]. Forming methane hydrate samples in the laboratory has been done a number of ways, each having advantages and disadvantages. The ice-to-hydrate method [Stern et al., 1996], contacts melting ice with methane at the appropriate pressure to form hydrate. The hydrate can then be crushed and mixed with mineral grains under controlled conditions, and then compacted to create laboratory samples of methane hydrate in a mineral medium. The hydrate in these samples will be part of the load-bearing frame of the medium. In the excess gas method [Handa and Stupin, 1992], water is distributed throughout a mineral medium (e.g. packed moist sand, drained sand, moistened silica gel, other porous media) and the mixture is brought to hydrate-stable conditions (chilled and pressurized with gas), allowing hydrate to form. This method typically produces grain-cementing hydrate from pendular water in sand [Waite et al., 2004]. In the dissolved gas method [Tohidi et al., 2002], water with sufficient dissolved guest molecules is brought to hydrate-stable conditions where hydrate forms. In the laboratory, this is can be done by pre-dissolving the gas of interest in water and then introducing it to the sample under the appropriate conditions. With this method, it is easier to form hydrate from more soluble gases such as carbon dioxide. It is thought that this method more closely simulates the way most natural gas hydrate has formed. Laboratory implementation, however, is difficult, and sample formation is prohibitively time consuming [Minagawa et al., 2005; Spangenberg and Kulenkampff, 2005]. In another version of this technique, a specified quantity of gas

Turbidity threshold sampling: Methods and instrumentation

Science.gov (United States)

Rand Eads; Jack Lewis

2001-01-01

Traditional methods for determining the frequency of suspended sediment sample collection often rely on measurements, such as water discharge, that are not well correlated to sediment concentration. Stream power is generally not a good predictor of sediment concentration for rivers that transport the bulk of their load as fines, due to the highly variable routing of...

Solid phase microextraction headspace sampling of chemical warfare agent contaminated samples : method development for GC-MS analysis

Energy Technology Data Exchange (ETDEWEB)

Jackson Lepage, C.R.; Hancock, J.R. [Defence Research and Development Canada, Medicine Hat, AB (Canada); Wyatt, H.D.M. [Regina Univ., SK (Canada)

2004-07-01

Defence R and D Canada-Suffield (DRDC-Suffield) is responsible for analyzing samples that are suspected to contain chemical warfare agents, either collected by the Canadian Forces or by first-responders in the event of a terrorist attack in Canada. The analytical techniques used to identify the composition of the samples include gas chromatography-mass spectrometry (GC-MS), liquid chromatography-mass spectrometry (LC-MS), Fourier-transform infrared spectroscopy (FT-IR) and nuclear magnetic resonance spectroscopy. GC-MS and LC-MS generally require solvent extraction and reconcentration, thereby increasing sample handling. The authors examined analytical techniques which reduce or eliminate sample manipulation. In particular, this paper presented a screening method based on solid phase microextraction (SPME) headspace sampling and GC-MS analysis for chemical warfare agents such as mustard, sarin, soman, and cyclohexyl methylphosphonofluoridate in contaminated soil samples. SPME is a method which uses small adsorbent polymer coated silica fibers that trap vaporous or liquid analytes for GC or LC analysis. Collection efficiency can be increased by adjusting sampling time and temperature. This method was tested on two real-world samples, one from excavated chemical munitions and the second from a caustic decontamination mixture. 7 refs., 2 tabs., 3 figs.

Model decontamination of PVC flooring specimens by wet method

International Nuclear Information System (INIS)

Severa, J.; Knajfl, J.; Bar, J.

1981-01-01

PVC flooring samples of 29 mm in diameter were used in experiments. The samples were degreased. Tested were the dependence of the degree of contamination on the duration of contact with the contaminant and the efficacy of decontamination by wiping with tampons and immersing in solutions. A mixture of fission products of 80 kBq/ml in specific activity was used for contamination. Higher decontamination efficacy was achieved by immersing the samples in decontamination solutions. Water was found to be the least efficacious medium; a high degree was only attained in the case when decontamination was effected within 1 minute after contamination. The highest decontamination values were achieved using solutions containing a chelating agent and a surfactant. The most efficacious solutions contained 0.5% of citric acid and 0.5% of detergents which are very potent at a concentration as low as 2 g/l. (J.P.)

Comparing residential contamination in a Houston environmental justice neighborhood before and after Hurricane Harvey.

Directory of Open Access Journals (Sweden)

Jennifer A Horney

Full Text Available Polycyclic aromatic hydrocarbons (PAHs are complex environmental toxicants. Exposure to them has been linked to adverse health outcomes including cancer, as well as diseases of the skin, liver, and immune system. Based on an ongoing community engagement partnership with stakeholder groups and residents, we conducted a small longitudinal study to assess domestic exposure to PAHs among residents of Manchester, an environmental justice neighborhood located in the East End of Houston, TX.In December, 2016, we used fiber wipes to collect samples of household dust from 25 homes in Manchester. Following Hurricane Harvey, in September 2017, we revisited 24 of the 25 homes to collect soil samples from the front yards of the same homes. Wipes and soil were analyzed for the presence of PAHs using gas chromatography-mass spectrometry (GC-MS methods. Principal component analysis plots, heatmaps, and PAH ratios were used to compare pre- and post-Hurricane Harvey samples.While direct comparison is not possible, we present three methods for comparing PAHs found in pre-hurricane fiber wipes and post-hurricane soil samples. The methods demonstrate that the PAHs found before and after Hurricane Harvey are likely from similar sources and that those sources are most likely to be associated with combustion. We also found evidence of redistribution of PAHs due to extreme flooding associated with Hurricane Harvey.Residents of the Manchester neighborhood of Houston, TX, are exposed to a range of PAHs in household dust and outdoor soil. While it was not possible to compare directly, we were able to use several methods to assess detected concentrations, changes in site-specific PAH allocations, and PAH origination. Additional research is needed to identify specific sources of domestic PAH exposure in these communities and continued work involving community members and policy makers should aim to develop interventions to reduce domestic exposure to and prevent negative

Validation of method in instrumental NAA for food products sample

International Nuclear Information System (INIS)

Alfian; Siti Suprapti; Setyo Purwanto

2010-01-01

NAA is a method of testing that has not been standardized. To affirm and confirm that this method is valid. it must be done validation of the method with various sample standard reference materials. In this work. the validation is carried for food product samples using NIST SRM 1567a (wheat flour) and NIST SRM 1568a (rice flour). The results show that the validation method for testing nine elements (Al, K, Mg, Mn, Na, Ca, Fe, Se and Zn) in SRM 1567a and eight elements (Al, K, Mg, Mn, Na, Ca, Se and Zn ) in SRM 1568a pass the test of accuracy and precision. It can be conclude that this method has power to give valid result in determination element of the food products samples. (author)

Validation of EIA sampling methods - bacterial and biochemical analysis

Digital Repository Service at National Institute of Oceanography (India)

Sheelu, G.; LokaBharathi, P.A.; Nair, S.; Raghukumar, C.; Mohandass, C.

to temporal factors. Paired T-test between pre- and post-disturbance samples suggested that the above methods of sampling and variables like TC, protein and TOC could be used for monitoring disturbance....

An efficient method for sampling the essential subspace of proteins

NARCIS (Netherlands)

Amadei, A; Linssen, A.B M; de Groot, B.L.; van Aalten, D.M.F.; Berendsen, H.J.C.

A method is presented for a more efficient sampling of the configurational space of proteins as compared to conventional sampling techniques such as molecular dynamics. The method is based on the large conformational changes in proteins revealed by the ''essential dynamics'' analysis. A form of

Measuring larval nematode contamination on cattle pastures: Comparing two herbage sampling methods.

Science.gov (United States)

Verschave, S H; Levecke, B; Duchateau, L; Vercruysse, J; Charlier, J

2015-06-15

Assessing levels of pasture larval contamination is frequently used to study the population dynamics of the free-living stages of parasitic nematodes of livestock. Direct quantification of infective larvae (L3) on herbage is the most applied method to measure pasture larval contamination. However, herbage collection remains labour intensive and there is a lack of studies addressing the variation induced by the sampling method and the required sample size. The aim of this study was (1) to compare two different sampling methods in terms of pasture larval count results and time required to sample, (2) to assess the amount of variation in larval counts at the level of sample plot, pasture and season, respectively and (3) to calculate the required sample size to assess pasture larval contamination with a predefined precision using random plots across pasture. Eight young stock pastures of different commercial dairy herds were sampled in three consecutive seasons during the grazing season (spring, summer and autumn). On each pasture, herbage samples were collected through both a double-crossed W-transect with samples taken every 10 steps (method 1) and four random located plots of 0.16 m(2) with collection of all herbage within the plot (method 2). The average (± standard deviation (SD)) pasture larval contamination using sampling methods 1 and 2 was 325 (± 479) and 305 (± 444)L3/kg dry herbage (DH), respectively. Large discrepancies in pasture larval counts of the same pasture and season were often seen between methods, but no significant difference (P = 0.38) in larval counts between methods was found. Less time was required to collect samples with method 2. This difference in collection time between methods was most pronounced for pastures with a surface area larger than 1 ha. The variation in pasture larval counts from samples generated by random plot sampling was mainly due to the repeated measurements on the same pasture in the same season (residual variance

Radioactivity level of airplane to Guangzhou Baiyun international airport during the Fukushima Daiichi nuclear power plant accident

International Nuclear Information System (INIS)

Song Haiqing; Chen Wentao; Cheng Xiaobo; Liao Tong; Deng Fei; Chen Fuliang; Zhang Yanjin; Li Lingjuan; Liang Guiyuan; Wu Guibiao

2014-01-01

The radioactivity level of airplanes to Guangzhou Baiyun International Airport (GBIAC) during the Fukushima Daiichi nuclear power plant accident was monitored by Guangdong Environmental Radiation Monitoring Center (GERC) on March 15 and 16, 2011. The artificial radionuclide "1"3"1I, "1"3"4Cs, "1"3"7Cs, "l"3"6Cs, "1"3"2I, "1"3"2Te were detected in the wipe samples of the outer surface of airplanes from Japan to GBIAC. The radioactivity ration of "1"3"7Cs/"1"3"4Cs was calculated as (1.12 ± 0.06) in the wipe samples, which similar to the result in the wipe sample of the outer surface of airplanes from Japan to Hangzhou airport obtained by Zhejiang Province Environmental Radiation Monitoring Center (l.lO ± 0.08), but slightly higher than results in the aerosol monitoring at Guangzhou (0.99 ± 0.30) and Shenzhen (0.94 ± 0.30) by GERC, the data (0.83) published by Japan Nuclear and Industrial Safety Agency (NISA) and the result (1.00 ± 0.13) measured by Tokyo Electric Power Company. A slight radioactive contamination was detected on the surface of outer airplanes and internal cabin. The practice suggested that the wipe sample of the outer surface of airplane was a fast , simple and sensitive approach for emergency monitoring of radioactive contamination. (authors)

Brachytherapy dose-volume histogram computations using optimized stratified sampling methods

International Nuclear Information System (INIS)

Karouzakis, K.; Lahanas, M.; Milickovic, N.; Giannouli, S.; Baltas, D.; Zamboglou, N.

2002-01-01

A stratified sampling method for the efficient repeated computation of dose-volume histograms (DVHs) in brachytherapy is presented as used for anatomy based brachytherapy optimization methods. The aim of the method is to reduce the number of sampling points required for the calculation of DVHs for the body and the PTV. From the DVHs are derived the quantities such as Conformity Index COIN and COIN integrals. This is achieved by using partial uniform distributed sampling points with a density in each region obtained from a survey of the gradients or the variance of the dose distribution in these regions. The shape of the sampling regions is adapted to the patient anatomy and the shape and size of the implant. For the application of this method a single preprocessing step is necessary which requires only a few seconds. Ten clinical implants were used to study the appropriate number of sampling points, given a required accuracy for quantities such as cumulative DVHs, COIN indices and COIN integrals. We found that DVHs of very large tissue volumes surrounding the PTV, and also COIN distributions, can be obtained using a factor of 5-10 times smaller the number of sampling points in comparison with uniform distributed points

Clustering Methods with Qualitative Data: a Mixed-Methods Approach for Prevention Research with Small Samples.

Science.gov (United States)

Henry, David; Dymnicki, Allison B; Mohatt, Nathaniel; Allen, James; Kelly, James G

2015-10-01

Qualitative methods potentially add depth to prevention research but can produce large amounts of complex data even with small samples. Studies conducted with culturally distinct samples often produce voluminous qualitative data but may lack sufficient sample sizes for sophisticated quantitative analysis. Currently lacking in mixed-methods research are methods allowing for more fully integrating qualitative and quantitative analysis techniques. Cluster analysis can be applied to coded qualitative data to clarify the findings of prevention studies by aiding efforts to reveal such things as the motives of participants for their actions and the reasons behind counterintuitive findings. By clustering groups of participants with similar profiles of codes in a quantitative analysis, cluster analysis can serve as a key component in mixed-methods research. This article reports two studies. In the first study, we conduct simulations to test the accuracy of cluster assignment using three different clustering methods with binary data as produced when coding qualitative interviews. Results indicated that hierarchical clustering, K-means clustering, and latent class analysis produced similar levels of accuracy with binary data and that the accuracy of these methods did not decrease with samples as small as 50. Whereas the first study explores the feasibility of using common clustering methods with binary data, the second study provides a "real-world" example using data from a qualitative study of community leadership connected with a drug abuse prevention project. We discuss the implications of this approach for conducting prevention research, especially with small samples and culturally distinct communities.

Clustering Methods with Qualitative Data: A Mixed Methods Approach for Prevention Research with Small Samples

Science.gov (United States)

Henry, David; Dymnicki, Allison B.; Mohatt, Nathaniel; Allen, James; Kelly, James G.

2016-01-01

Qualitative methods potentially add depth to prevention research, but can produce large amounts of complex data even with small samples. Studies conducted with culturally distinct samples often produce voluminous qualitative data, but may lack sufficient sample sizes for sophisticated quantitative analysis. Currently lacking in mixed methods research are methods allowing for more fully integrating qualitative and quantitative analysis techniques. Cluster analysis can be applied to coded qualitative data to clarify the findings of prevention studies by aiding efforts to reveal such things as the motives of participants for their actions and the reasons behind counterintuitive findings. By clustering groups of participants with similar profiles of codes in a quantitative analysis, cluster analysis can serve as a key component in mixed methods research. This article reports two studies. In the first study, we conduct simulations to test the accuracy of cluster assignment using three different clustering methods with binary data as produced when coding qualitative interviews. Results indicated that hierarchical clustering, K-Means clustering, and latent class analysis produced similar levels of accuracy with binary data, and that the accuracy of these methods did not decrease with samples as small as 50. Whereas the first study explores the feasibility of using common clustering methods with binary data, the second study provides a “real-world” example using data from a qualitative study of community leadership connected with a drug abuse prevention project. We discuss the implications of this approach for conducting prevention research, especially with small samples and culturally distinct communities. PMID:25946969

Soybean yield modeling using bootstrap methods for small samples

Energy Technology Data Exchange (ETDEWEB)

Dalposso, G.A.; Uribe-Opazo, M.A.; Johann, J.A.

2016-11-01

One of the problems that occur when working with regression models is regarding the sample size; once the statistical methods used in inferential analyzes are asymptotic if the sample is small the analysis may be compromised because the estimates will be biased. An alternative is to use the bootstrap methodology, which in its non-parametric version does not need to guess or know the probability distribution that generated the original sample. In this work we used a set of soybean yield data and physical and chemical soil properties formed with fewer samples to determine a multiple linear regression model. Bootstrap methods were used for variable selection, identification of influential points and for determination of confidence intervals of the model parameters. The results showed that the bootstrap methods enabled us to select the physical and chemical soil properties, which were significant in the construction of the soybean yield regression model, construct the confidence intervals of the parameters and identify the points that had great influence on the estimated parameters. (Author)

Radiochemistry methods in DOE Methods for Evaluating Environmental and Waste Management Samples: Addressing new challenges

International Nuclear Information System (INIS)

Fadeff, S.K.; Goheen, S.C.; Riley, R.G.

1994-01-01

Radiochemistry methods in Department of Energy Methods for Evaluating Environmental and Waste Management Samples (DOE Methods) add to the repertoire of other standard methods in support of U.S. Department of Energy environmental restoration and waste management (DOE/EM) radiochemical characterization activities. Current standard sources of radiochemistry methods are not always applicable for evaluating DOE/EM samples. Examples of current sources include those provided by the US Environmental Protection Agency, the American Society for Testing and Materials, Standard Methods for the Examination of Water and Wastewater, and Environmental Measurements Laboratory Procedures Manual (HASL-300). The applicability of these methods is generally limited to specific matrices (usually water), low-level radioactive samples, and a limited number of analytes. DOE Methods complements these current standard methods by addressing the complexities of EM characterization needs. The process for determining DOE/EM radiochemistry characterization needs is discussed. In this context of DOE/EM needs, the applicability of other sources of standard radiochemistry methods is defined, and gaps in methodology are identified. Current methods in DOE Methods and the EM characterization needs they address are discussed. Sources of new methods and the methods incorporation process are discussed. The means for individuals to participate in (1) identification of DOE/EM needs, (2) the methods incorporation process, and (3) submission of new methods are identified

A comprehensive comparison of perpendicular distance sampling methods for sampling downed coarse woody debris

Science.gov (United States)

Jeffrey H. Gove; Mark J. Ducey; Harry T. Valentine; Michael S. Williams

2013-01-01

Many new methods for sampling down coarse woody debris have been proposed in the last dozen or so years. One of the most promising in terms of field application, perpendicular distance sampling (PDS), has several variants that have been progressively introduced in the literature. In this study, we provide an overview of the different PDS variants and comprehensive...

A comparison of fitness-case sampling methods for genetic programming

Science.gov (United States)

Martínez, Yuliana; Naredo, Enrique; Trujillo, Leonardo; Legrand, Pierrick; López, Uriel

2017-11-01

Genetic programming (GP) is an evolutionary computation paradigm for automatic program induction. GP has produced impressive results but it still needs to overcome some practical limitations, particularly its high computational cost, overfitting and excessive code growth. Recently, many researchers have proposed fitness-case sampling methods to overcome some of these problems, with mixed results in several limited tests. This paper presents an extensive comparative study of four fitness-case sampling methods, namely: Interleaved Sampling, Random Interleaved Sampling, Lexicase Selection and Keep-Worst Interleaved Sampling. The algorithms are compared on 11 symbolic regression problems and 11 supervised classification problems, using 10 synthetic benchmarks and 12 real-world data-sets. They are evaluated based on test performance, overfitting and average program size, comparing them with a standard GP search. Comparisons are carried out using non-parametric multigroup tests and post hoc pairwise statistical tests. The experimental results suggest that fitness-case sampling methods are particularly useful for difficult real-world symbolic regression problems, improving performance, reducing overfitting and limiting code growth. On the other hand, it seems that fitness-case sampling cannot improve upon GP performance when considering supervised binary classification.

Shear Strength of Remoulding Clay Samples Using Different Methods of Moulding

Science.gov (United States)

Norhaliza, W.; Ismail, B.; Azhar, A. T. S.; Nurul, N. J.

2016-07-01

Shear strength for clay soil was required to determine the soil stability. Clay was known as a soil with complex natural formations and very difficult to obtain undisturbed samples at the site. The aim of this paper was to determine the unconfined shear strength of remoulded clay on different methods in moulding samples which were proctor compaction, hand operated soil compacter and miniature mould methods. All the samples were remoulded with the same optimum moisture content (OMC) and density that were 18% and 1880 kg/m3 respectively. The unconfined shear strength results of remoulding clay soils for proctor compaction method was 289.56kPa with the strain 4.8%, hand operated method was 261.66kPa with the strain 4.4% and miniature mould method was 247.52kPa with the strain 3.9%. Based on the proctor compaction method, the reduction percentage of unconfined shear strength of remoulded clay soil of hand operated method was 9.66%, and for miniature mould method was 14.52%. Thus, because there was no significant difference of reduction percentage of unconfined shear strength between three different methods, so it can be concluded that remoulding clay by hand operated method and miniature mould method were accepted and suggested to perform remoulding clay samples by other future researcher. However for comparison, the hand operated method was more suitable to form remoulded clay sample in term of easiness, saving time and less energy for unconfined shear strength determination purposes.

A multi-dimensional sampling method for locating small scatterers

International Nuclear Information System (INIS)

Song, Rencheng; Zhong, Yu; Chen, Xudong

2012-01-01

A multiple signal classification (MUSIC)-like multi-dimensional sampling method (MDSM) is introduced to locate small three-dimensional scatterers using electromagnetic waves. The indicator is built with the most stable part of signal subspace of the multi-static response matrix on a set of combinatorial sampling nodes inside the domain of interest. It has two main advantages compared to the conventional MUSIC methods. First, the MDSM is more robust against noise. Second, it can work with a single incidence even for multi-scatterers. Numerical simulations are presented to show the good performance of the proposed method. (paper)

Efficiency of snake sampling methods in the Brazilian semiarid region.

Science.gov (United States)

Mesquita, Paula C M D; Passos, Daniel C; Cechin, Sonia Z

2013-09-01

The choice of sampling methods is a crucial step in every field survey in herpetology. In countries where time and financial support are limited, the choice of the methods is critical. The methods used to sample snakes often lack objective criteria, and the traditional methods have apparently been more important when making the choice. Consequently researches using not-standardized methods are frequently found in the literature. We have compared four commonly used methods for sampling snake assemblages in a semiarid area in Brazil. We compared the efficacy of each method based on the cost-benefit regarding the number of individuals and species captured, time, and financial investment. We found that pitfall traps were the less effective method in all aspects that were evaluated and it was not complementary to the other methods in terms of abundance of species and assemblage structure. We conclude that methods can only be considered complementary if they are standardized to the objectives of the study. The use of pitfall traps in short-term surveys of the snake fauna in areas with shrubby vegetation and stony soil is not recommended.

Methods for Characterisation of unknown Suspect Radioactive Samples

International Nuclear Information System (INIS)

Sahagia, M.; Grigorescu, E.L.; Luca, A.; Razdolescu, A.C.; Ivan, C.

2001-01-01

Full text: The paper presents various identification and measurement methods, used for the expertise of a wide variety of suspect radioactive materials, whose circulation was not legally stated. The main types of examined samples were: radioactive sources, illegally trafficked; suspect radioactive materials or radioactively contaminated devices; uranium tablets; fire detectors containing 241 Am sources; osmium samples containing radioactive 185 Os or enriched 187 Os. The types of analyses and determination methods were as follows: the chemical composition was determined by using identification reagents or by neutron activation analysis; the radionuclide composition was determined by using gamma-ray spectrometry; the activity and particle emission rates were determined by using calibrated radiometric equipment; the absorbed dose rate at the wall of all types of containers and samples was determined by using calibrated dose ratemeters. The radiation exposure risk for population, due to these radioactive materials, was evaluated for every case. (author)

Multielement methods of atomic fluorescence analysis of enviromental samples

International Nuclear Information System (INIS)

Rigin, V.I.

1985-01-01

A multielement method of atomic fluorescence analysis of environmental samples based on sample decomposition by autoclave fluorination and gas-phase atomization of volatile compounds in inductive araon plasma using a nondispersive polychromator is suggested. Detection limits of some elements (Be, Sr, Cd, V, Mo, Te, Ru etc.) for different sample forms introduced in to an analyzer are given

A DOE manual: DOE Methods for Evaluating Environmental and Waste Management Samples

International Nuclear Information System (INIS)

Goheen, S.C.; McCulloch, M.; Riley, R.G.

1994-01-01

Waste Management inherently requires knowledge of the waste's chemical composition. The waste can often be analyzed by established methods; however, if the samples are radioactive, or are plagued by other complications, established methods may not be feasible. The US Department of Energy (DOE) has been faced with managing some waste types that are not amenable to standard or available methods, so new or modified sampling and analysis methods are required. These methods are incorporated into DOE Methods for Evaluating Environmental and Waste Management Samples (DOE Methods), which is a guidance/methods document for sampling and analysis activities in support of DOE sites. It is a document generated by consensus of the DOE laboratory staff and is intended to fill the gap within existing guidance documents (e. g., the Environmental Protection Agency's (EPA's) Test Methods for Evaluating Solid Waste, SW-846), which apply to low-level or non-radioactive samples. DOE Methods fills the gap by including methods that take into account the complexities of DOE site matrices. The most recent update, distributed in October 1993, contained quality assurance (QA), quality control (QC), safety, sampling, organic analysis, inorganic analysis, and radioanalytical guidance as well as 29 methods. The next update, which will be distributed in April 1994, will contain 40 methods and will therefore have greater applicability. All new methods are either peer reviewed or labeled ''draft'' methods. Draft methods were added to speed the release of methods to field personnel

Sampling and sample preparation methods for the analysis of trace elements in biological material

International Nuclear Information System (INIS)

Sansoni, B.; Iyengar, V.

1978-05-01

The authors attempt to give a most systamtic possible treatment of the sample taking and sample preparation of biological material (particularly in human medicine) for trace analysis (e.g. neutron activation analysis, atomic absorption spectrometry). Contamination and loss problems are discussed as well as the manifold problems of the different consistency of solid and liquid biological materials, as well as the stabilization of the sample material. The process of dry and wet ashing is particularly dealt with, where new methods are also described. (RB) [de

[Progress in sample preparation and analytical methods for trace polar small molecules in complex samples].

Science.gov (United States)

Zhang, Qianchun; Luo, Xialin; Li, Gongke; Xiao, Xiaohua

2015-09-01

Small polar molecules such as nucleosides, amines, amino acids are important analytes in biological, food, environmental, and other fields. It is necessary to develop efficient sample preparation and sensitive analytical methods for rapid analysis of these polar small molecules in complex matrices. Some typical materials in sample preparation, including silica, polymer, carbon, boric acid and so on, are introduced in this paper. Meanwhile, the applications and developments of analytical methods of polar small molecules, such as reversed-phase liquid chromatography, hydrophilic interaction chromatography, etc., are also reviewed.

Methods of sampling airborne fungi in working environments of waste treatment facilities.

Science.gov (United States)

Černá, Kristýna; Wittlingerová, Zdeňka; Zimová, Magdaléna; Janovský, Zdeněk

2016-01-01

The objective of the present study was to evaluate and compare the efficiency of a filter based sampling method and a high volume sampling method for sampling airborne culturable fungi present in waste sorting facilities. Membrane filters method was compared with surface air system method. The selected sampling methods were modified and tested in 2 plastic waste sorting facilities. The total number of colony-forming units (CFU)/m3 of airborne fungi was dependent on the type of sampling device, on the time of sampling, which was carried out every hour from the beginning of the work shift, and on the type of cultivation medium (p airborne fungi ranged 2×102-1.7×106 CFU/m3 when using the membrane filters (MF) method, and 3×102-6.4×104 CFU/m3 when using the surface air system (SAS) method. Both methods showed comparable sensitivity to the fluctuations of the concentrations of airborne fungi during the work shifts. The SAS method is adequate for a fast indicative determination of concentration of airborne fungi. The MF method is suitable for thorough assessment of working environment contamination by airborne fungi. Therefore we recommend the MF method for the implementation of a uniform standard methodology of airborne fungi sampling in working environments of waste treatment facilities. This work is available in Open Access model and licensed under a CC BY-NC 3.0 PL license.

Single- versus multiple-sample method to measure glomerular filtration rate.

Science.gov (United States)

Delanaye, Pierre; Flamant, Martin; Dubourg, Laurence; Vidal-Petiot, Emmanuelle; Lemoine, Sandrine; Cavalier, Etienne; Schaeffner, Elke; Ebert, Natalie; Pottel, Hans

2018-01-08

There are many different ways to measure glomerular filtration rate (GFR) using various exogenous filtration markers, each having their own strengths and limitations. However, not only the marker, but also the methodology may vary in many ways, including the use of urinary or plasma clearance, and, in the case of plasma clearance, the number of time points used to calculate the area under the concentration-time curve, ranging from only one (Jacobsson method) to eight (or more) blood samples. We collected the results obtained from 5106 plasma clearances (iohexol or 51Cr-ethylenediaminetetraacetic acid (EDTA)) using three to four time points, allowing GFR calculation using the slope-intercept method and the Bröchner-Mortensen correction. For each time point, the Jacobsson formula was applied to obtain the single-sample GFR. We used Bland-Altman plots to determine the accuracy of the Jacobsson method at each time point. The single-sample method showed within 10% concordances with the multiple-sample method of 66.4%, 83.6%, 91.4% and 96.0% at the time points 120, 180, 240 and ≥300 min, respectively. Concordance was poorer at lower GFR levels, and this trend is in parallel with increasing age. Results were similar in males and females. Some discordance was found in the obese subjects. Single-sample GFR is highly concordant with a multiple-sample strategy, except in the low GFR range (<30 mL/min). © The Author 2018. Published by Oxford University Press on behalf of ERA-EDTA. All rights reserved.

Surveying immigrants without sampling frames - evaluating the success of alternative field methods.

Science.gov (United States)

Reichel, David; Morales, Laura

2017-01-01

This paper evaluates the sampling methods of an international survey, the Immigrant Citizens Survey, which aimed at surveying immigrants from outside the European Union (EU) in 15 cities in seven EU countries. In five countries, no sample frame was available for the target population. Consequently, alternative ways to obtain a representative sample had to be found. In three countries 'location sampling' was employed, while in two countries traditional methods were used with adaptations to reach the target population. The paper assesses the main methodological challenges of carrying out a survey among a group of immigrants for whom no sampling frame exists. The samples of the survey in these five countries are compared to results of official statistics in order to assess the accuracy of the samples obtained through the different sampling methods. It can be shown that alternative sampling methods can provide meaningful results in terms of core demographic characteristics although some estimates differ to some extent from the census results.

Sampling and analysis methods for geothermal fluids and gases

Energy Technology Data Exchange (ETDEWEB)

Shannon, D. W.

1978-01-01

The data obtained for the first round robin sample collected at Mesa 6-2 wellhead, East Mesa Test Site, Imperial Valley are summarized. Test results are listed by method used for cross reference to the analytic methods section. Results obtained for radioactive isotopes present in the brine sample are tabulated. The data obtained for the second round robin sample collected from the Woolsey No. 1 first stage flash unit, San Diego Gas and Electric Niland Test Facility are presented in the same manner. Lists of the participants of the two round robins are given. Data from miscellaneous analyses are included. Summaries of values derived from the round robin raw data are presented. (MHR)

Efficient free energy calculations by combining two complementary tempering sampling methods.

Science.gov (United States)

Xie, Liangxu; Shen, Lin; Chen, Zhe-Ning; Yang, Mingjun

2017-01-14

Although energy barriers can be efficiently crossed in the reaction coordinate (RC) guided sampling, this type of method suffers from identification of the correct RCs or requirements of high dimensionality of the defined RCs for a given system. If only the approximate RCs with significant barriers are used in the simulations, hidden energy barriers with small to medium height would exist in other degrees of freedom (DOFs) relevant to the target process and consequently cause the problem of insufficient sampling. To address the sampling in this so-called hidden barrier situation, here we propose an effective approach to combine temperature accelerated molecular dynamics (TAMD), an efficient RC-guided sampling method, with the integrated tempering sampling (ITS), a generalized ensemble sampling method. In this combined ITS-TAMD method, the sampling along the major RCs with high energy barriers is guided by TAMD and the sampling of the rest of the DOFs with lower but not negligible barriers is enhanced by ITS. The performance of ITS-TAMD to three systems in the processes with hidden barriers has been examined. In comparison to the standalone TAMD or ITS approach, the present hybrid method shows three main improvements. (1) Sampling efficiency can be improved at least five times even if in the presence of hidden energy barriers. (2) The canonical distribution can be more accurately recovered, from which the thermodynamic properties along other collective variables can be computed correctly. (3) The robustness of the selection of major RCs suggests that the dimensionality of necessary RCs can be reduced. Our work shows more potential applications of the ITS-TAMD method as the efficient and powerful tool for the investigation of a broad range of interesting cases.

SnagPRO: snag and tree sampling and analysis methods for wildlife

Science.gov (United States)

Lisa J. Bate; Michael J. Wisdom; Edward O. Garton; Shawn C. Clabough

2008-01-01

We describe sampling methods and provide software to accurately and efficiently estimate snag and tree densities at desired scales to meet a variety of research and management objectives. The methods optimize sampling effort by choosing a plot size appropriate for the specified forest conditions and sampling goals. Plot selection and data analyses are supported by...

Soil separator and sampler and method of sampling

Science.gov (United States)

O'Brien, Barry H [Idaho Falls, ID; Ritter, Paul D [Idaho Falls, ID

2010-02-16

A soil sampler includes a fluidized bed for receiving a soil sample. The fluidized bed may be in communication with a vacuum for drawing air through the fluidized bed and suspending particulate matter of the soil sample in the air. In a method of sampling, the air may be drawn across a filter, separating the particulate matter. Optionally, a baffle or a cyclone may be included within the fluidized bed for disentrainment, or dedusting, so only the finest particulate matter, including asbestos, will be trapped on the filter. The filter may be removable, and may be tested to determine the content of asbestos and other hazardous particulate matter in the soil sample.

Detecting spatial structures in throughfall data: The effect of extent, sample size, sampling design, and variogram estimation method

Science.gov (United States)

Voss, Sebastian; Zimmermann, Beate; Zimmermann, Alexander

2016-09-01

In the last decades, an increasing number of studies analyzed spatial patterns in throughfall by means of variograms. The estimation of the variogram from sample data requires an appropriate sampling scheme: most importantly, a large sample and a layout of sampling locations that often has to serve both variogram estimation and geostatistical prediction. While some recommendations on these aspects exist, they focus on Gaussian data and high ratios of the variogram range to the extent of the study area. However, many hydrological data, and throughfall data in particular, do not follow a Gaussian distribution. In this study, we examined the effect of extent, sample size, sampling design, and calculation method on variogram estimation of throughfall data. For our investigation, we first generated non-Gaussian random fields based on throughfall data with large outliers. Subsequently, we sampled the fields with three extents (plots with edge lengths of 25 m, 50 m, and 100 m), four common sampling designs (two grid-based layouts, transect and random sampling) and five sample sizes (50, 100, 150, 200, 400). We then estimated the variogram parameters by method-of-moments (non-robust and robust estimators) and residual maximum likelihood. Our key findings are threefold. First, the choice of the extent has a substantial influence on the estimation of the variogram. A comparatively small ratio of the extent to the correlation length is beneficial for variogram estimation. Second, a combination of a minimum sample size of 150, a design that ensures the sampling of small distances and variogram estimation by residual maximum likelihood offers a good compromise between accuracy and efficiency. Third, studies relying on method-of-moments based variogram estimation may have to employ at least 200 sampling points for reliable variogram estimates. These suggested sample sizes exceed the number recommended by studies dealing with Gaussian data by up to 100 %. Given that most previous

Culture methods of allograft musculoskeletal tissue samples in Australian bacteriology laboratories.

Science.gov (United States)

Varettas, Kerry

2013-12-01

Samples of allograft musculoskeletal tissue are cultured by bacteriology laboratories to determine the presence of bacteria and fungi. In Australia, this testing is performed by 6 TGA-licensed clinical bacteriology laboratories with samples received from 10 tissue banks. Culture methods of swab and tissue samples employ a combination of solid agar and/or broth media to enhance micro-organism growth and maximise recovery. All six Australian laboratories receive Amies transport swabs and, except for one laboratory, a corresponding biopsy sample for testing. Three of the 6 laboratories culture at least one allograft sample directly onto solid agar. Only one laboratory did not use a broth culture for any sample received. An international literature review found that a similar combination of musculoskeletal tissue samples were cultured onto solid agar and/or broth media. Although variations of allograft musculoskeletal tissue samples, culture media and methods are used in Australian and international bacteriology laboratories, validation studies and method evaluations have challenged and supported their use in recovering fungi and aerobic and anaerobic bacteria.

Phthalates and alternative plasticizers and potential for contact exposure from children's backpacks and toys.

Science.gov (United States)

Xie, Mingjie; Wu, Yaoxing; Little, John C; Marr, Linsey C

2016-01-01

This work focuses on the mass content of plasticizers in children's backpacks and toys, and their mass transfer from product surfaces to cotton wipes. The mass content of plasticizers in six backpacks and seven toys was measured by extracting them in tetrahydrofuran. Bis(2-ethylhexyl) terephthalate (DEHT) was the most common plasticizer, dominating the composition of plasticizers in four backpacks (average mass content in product polyvinyl chloride, 5.38 ± 1.98%-25.5 ± 3.54%) and six plastic toys (8.17 ± 1.85%-21.2 ± 1.11%). The surface of each product was wiped with three dry and three wet (by isopropanol) cotton wipes, so as to evaluate the mass transfer of plasticizers to clothing and human skin, respectively. DEHT was the most common plasticizer detected on wipe samples. There were strong correlations (backpacks r=0.90; plastic toys r=0.96) between average mass transfer of DEHT to wet wipes and its average mass content in the product. The mass transfers of the five dominant plasticizers in one backpack to both dry and wet wipes were also correlated (both r=1.00) with their mass contents. These results suggest that the mass transfer of plasticizers from products to clothing or human skin is strongly associated with their mass content.

Detection of protozoa in water samples by formalin/ether concentration method.

Science.gov (United States)

Lora-Suarez, Fabiana; Rivera, Raul; Triviño-Valencia, Jessica; Gomez-Marin, Jorge E

2016-09-01

Methods to detect protozoa in water samples are expensive and laborious. We evaluated the formalin/ether concentration method to detect Giardia sp., Cryptosporidium sp. and Toxoplasma in water. In order to test the properties of the method, we spiked water samples with different amounts of each protozoa (0, 10 and 50 cysts or oocysts) in a volume of 10 L of water. Immunofluorescence assay was used for detection of Giardia and Cryptosporidium. Toxoplasma oocysts were identified by morphology. The mean percent of recovery in 10 repetitions of the entire method, in 10 samples spiked with ten parasites and read by three different observers, were for Cryptosporidium 71.3 ± 12, for Giardia 63 ± 10 and for Toxoplasma 91.6 ± 9 and the relative standard deviation of the method was of 17.5, 17.2 and 9.8, respectively. Intraobserver variation as measured by intraclass correlation coefficient, was fair for Toxoplasma, moderate for Cryptosporidium and almost perfect for Giardia. The method was then applied in 77 samples of raw and drinkable water in three different plant of water treatment. Cryptosporidium was found in 28 of 77 samples (36%) and Giardia in 31 of 77 samples (40%). Theses results identified significant differences in treatment process to reduce the presence of Giardia and Cryptosporidium. In conclusion, the formalin ether method to concentrate protozoa in water is a new alternative for low resources countries, where is urgently need to monitor and follow the presence of theses protozoa in drinkable water. Copyright © 2016 Elsevier Ltd. All rights reserved.

Comparison of sampling methods for radiocarbon dating of carbonyls in air samples via accelerator mass spectrometry

Energy Technology Data Exchange (ETDEWEB)

Schindler, Matthias, E-mail: matthias.schindler@physik.uni-erlangen.de; Kretschmer, Wolfgang; Scharf, Andreas; Tschekalinskij, Alexander

2016-05-15

Three new methods to sample and prepare various carbonyl compounds for radiocarbon measurements were developed and tested. Two of these procedures utilized the Strecker synthetic method to form amino acids from carbonyl compounds with either sodium cyanide or trimethylsilyl cyanide. The third procedure used semicarbazide to form crystalline carbazones with the carbonyl compounds. The resulting amino acids and semicarbazones were then separated and purified using thin layer chromatography. The separated compounds were then combusted to CO{sub 2} and reduced to graphite to determine {sup 14}C content by accelerator mass spectrometry (AMS). All of these methods were also compared with the standard carbonyl compound sampling method wherein a compound is derivatized with 2,4-dinitrophenylhydrazine and then separated by high-performance liquid chromatography (HPLC).

Comparison of sampling methods for radiocarbon dating of carbonyls in air samples via accelerator mass spectrometry

Science.gov (United States)

Schindler, Matthias; Kretschmer, Wolfgang; Scharf, Andreas; Tschekalinskij, Alexander

2016-05-01

Three new methods to sample and prepare various carbonyl compounds for radiocarbon measurements were developed and tested. Two of these procedures utilized the Strecker synthetic method to form amino acids from carbonyl compounds with either sodium cyanide or trimethylsilyl cyanide. The third procedure used semicarbazide to form crystalline carbazones with the carbonyl compounds. The resulting amino acids and semicarbazones were then separated and purified using thin layer chromatography. The separated compounds were then combusted to CO2 and reduced to graphite to determine 14C content by accelerator mass spectrometry (AMS). All of these methods were also compared with the standard carbonyl compound sampling method wherein a compound is derivatized with 2,4-dinitrophenylhydrazine and then separated by high-performance liquid chromatography (HPLC).

Assessment of reagent effectiveness and preservation methods for equine faecal samples

Directory of Open Access Journals (Sweden)

Eva Vavrouchova

2015-03-01

Full Text Available The aim of our study was to identify the most suitable flotation solution and effective preservation method for the examination of equine faeces samples using the FLOTAC technique. Samples from naturally infected horses were transported to the laboratory andanalysed accordingly. The sample from each horse was homogenized and divided into four parts: one was frozen, another two were preserved in different reagents such as sodium acetate-acetic-acid–formalin (SAF or 5% formalin.The last part was examined as a fresh sample in three different flotation solutions (Sheather´s solution, sodium chloride and sodium nitrate solution, all with a specific gravity 1.200. The preserved samples were examined in the period from 14 to21days after collection. According to our results, the sucrose solution was the most suitable flotation solution for fresh samples (small strongyle egg per gram was 706 compared to 360 in sodium chlorid and 507 in sodium nitrate and the sodium nitrate solution was the most efficient for the preserved samples (egg per gram was 382 compared to 295 in salt solution and 305 in sucrose solution. Freezing appears to be the most effective method of sample preservation, resulting in minimal damage to fragile strongyle eggs and therefore it is the most simple and effective preservation method for the examination of large numbers of faecal samples without the necessity of examining them all within 48 hours of collection. Deep freezing as a preservation method for equine faeces samples has not, according to our knowledge, been yet published.

Effectiveness of various cleaning and disinfectant products on Clostridium difficile spores of PCR ribotypes 010, 014 and 027

Directory of Open Access Journals (Sweden)

N. Kenters

2017-06-01

Full Text Available Abstract Background In healthcare facilities, Clostridium difficile infections spread by transmission of bacterial spores. Appropriate sporicidal disinfectants are needed to prevent development of clusters and outbreaks. In this study different cleaning/disinfecting wipes and sprays were tested for their efficacy against spores of distinctive C. difficile PCR ribotypes. Methods Four different products were tested; 1 hydrogen peroxide 1.5%; 2 glucoprotamin 1.5%; 3 a mixture of ethanol, propane and N-alkyl amino propyl glycine; and 4 a mixture of didecyldimonium chloride, benzalkonium chloride, polyaminopropyl, biguanide and dimenthicone as active ingredients. Tiles were contaminated with a test solution containing a concentration of 5x106CFU/ml spores of C. difficile strains belonging to PCR ribotypes 010, 014 or 027. The tiles were left to dry for an hour and then wiped or sprayed with one of the sprays or wipes as intended by the manufacturers. When products neutralized after 5 min, microbiological cultures and ATP measures were performed. Results Irrespective of the disinfection method, the microbial count log10 reduction of C. difficile PCR ribotype 010 was highest, followed by the reduction of C. difficile 014 and C. difficile 027. Overall, the wipes performed better than the sprays with the same active ingredient. On average, although not significantly, a difference in relative light units (RLU reduction between the wipes and sprays was found. The wipes had a higher RLU log10 reduction, but no significant difference for RLU reduction was observed between the different C. difficile strains (p = 0.16. Conclusion C. difficile spores of PCR ribotypes 014 and 027 strains are more difficult to eradicate than non-toxigenic PCR ribotype 010. In general, impregnated cleaning/disinfection wipes performed better than ready-to-use sprays. Wipes with hydrogen peroxide (1.5% showed the highest bactericidal activity.

Extending the alias Monte Carlo sampling method to general distributions

International Nuclear Information System (INIS)

Edwards, A.L.; Rathkopf, J.A.; Smidt, R.K.

1991-01-01

The alias method is a Monte Carlo sampling technique that offers significant advantages over more traditional methods. It equals the accuracy of table lookup and the speed of equal probable bins. The original formulation of this method sampled from discrete distributions and was easily extended to histogram distributions. We have extended the method further to applications more germane to Monte Carlo particle transport codes: continuous distributions. This paper presents the alias method as originally derived and our extensions to simple continuous distributions represented by piecewise linear functions. We also present a method to interpolate accurately between distributions tabulated at points other than the point of interest. We present timing studies that demonstrate the method's increased efficiency over table lookup and show further speedup achieved through vectorization. 6 refs., 12 figs., 2 tabs

Research and application of sampling and analysis method of sodium aerosol

International Nuclear Information System (INIS)

Yu Xiaochen; Guo Qingzhou; Wen Ximeng

1998-01-01

Method of sampling-analysis for sodium aerosol is researched. The vacuum sampling technology is used in the sampling process, and the analysis method adopted is volumetric analysis and atomic absorption. When the absolute content of sodium is in the rang of 0.1 mg to 1.0 mg, the deviation of results between volumetric analysis and atomic absorption is less than 2%. The method has been applied in a sodium aerosol removal device successfully. The analysis range, accuracy and precision can meet the requirements for researching sodium aerosol

A novel method for fission product noble gas sampling

International Nuclear Information System (INIS)

Jain, S.K.; Prakash, Vivek; Singh, G.K.; Vinay, Kr.; Awsthi, A.; Bihari, K.; Joyson, R.; Manu, K.; Gupta, Ashok

2008-01-01

Noble gases occur to some extent in the Earth's atmosphere, but the concentrations of all but argon are exceedingly low. Argon is plentiful, constituting almost 1 % of the air. Fission Product Noble Gases (FPNG) are produced by nuclear fission and large parts of FPNG is produced in Nuclear reactions. FPNG are b-j emitters and contributing significantly in public dose. During normal operation of reactor release of FPNG is negligible but its release increases in case of fuel failure. Xenon, a member of FPNG family helps in identification of fuel failure and its extent in PHWRs. Due to above reasons it becomes necessary to assess the FPNG release during operation of NPPs. Presently used methodology of assessment of FPNG, at almost all power stations is Computer based gamma ray spectrometry. This provides fission product Noble gases nuclide identification through peak search of spectra. The air sample for the same is collected by grab sampling method, which has inherent disadvantages. An alternate method was developed at Rajasthan Atomic Power Station (RAPS) - 3 and 4 for assessment of FPNG, which uses adsorption phenomena for collection of air samples. This report presents details of sampling method for FPNG and noble gases in different systems of Nuclear Power Plant. (author)

Transformation-cost time-series method for analyzing irregularly sampled data.

Science.gov (United States)

Ozken, Ibrahim; Eroglu, Deniz; Stemler, Thomas; Marwan, Norbert; Bagci, G Baris; Kurths, Jürgen

2015-06-01

Irregular sampling of data sets is one of the challenges often encountered in time-series analysis, since traditional methods cannot be applied and the frequently used interpolation approach can corrupt the data and bias the subsequence analysis. Here we present the TrAnsformation-Cost Time-Series (TACTS) method, which allows us to analyze irregularly sampled data sets without degenerating the quality of the data set. Instead of using interpolation we consider time-series segments and determine how close they are to each other by determining the cost needed to transform one segment into the following one. Using a limited set of operations-with associated costs-to transform the time series segments, we determine a new time series, that is our transformation-cost time series. This cost time series is regularly sampled and can be analyzed using standard methods. While our main interest is the analysis of paleoclimate data, we develop our method using numerical examples like the logistic map and the Rössler oscillator. The numerical data allows us to test the stability of our method against noise and for different irregular samplings. In addition we provide guidance on how to choose the associated costs based on the time series at hand. The usefulness of the TACTS method is demonstrated using speleothem data from the Secret Cave in Borneo that is a good proxy for paleoclimatic variability in the monsoon activity around the maritime continent.

Transformation-cost time-series method for analyzing irregularly sampled data

Science.gov (United States)

Ozken, Ibrahim; Eroglu, Deniz; Stemler, Thomas; Marwan, Norbert; Bagci, G. Baris; Kurths, Jürgen

2015-06-01

Irregular sampling of data sets is one of the challenges often encountered in time-series analysis, since traditional methods cannot be applied and the frequently used interpolation approach can corrupt the data and bias the subsequence analysis. Here we present the TrAnsformation-Cost Time-Series (TACTS) method, which allows us to analyze irregularly sampled data sets without degenerating the quality of the data set. Instead of using interpolation we consider time-series segments and determine how close they are to each other by determining the cost needed to transform one segment into the following one. Using a limited set of operations—with associated costs—to transform the time series segments, we determine a new time series, that is our transformation-cost time series. This cost time series is regularly sampled and can be analyzed using standard methods. While our main interest is the analysis of paleoclimate data, we develop our method using numerical examples like the logistic map and the Rössler oscillator. The numerical data allows us to test the stability of our method against noise and for different irregular samplings. In addition we provide guidance on how to choose the associated costs based on the time series at hand. The usefulness of the TACTS method is demonstrated using speleothem data from the Secret Cave in Borneo that is a good proxy for paleoclimatic variability in the monsoon activity around the maritime continent.

Different methods for volatile sampling in mammals.

Directory of Open Access Journals (Sweden)

Marlen Kücklich

Full Text Available Previous studies showed that olfactory cues are important for mammalian communication. However, many specific compounds that convey information between conspecifics are still unknown. To understand mechanisms and functions of olfactory cues, olfactory signals such as volatile compounds emitted from individuals need to be assessed. Sampling of animals with and without scent glands was typically conducted using cotton swabs rubbed over the skin or fur and analysed by gas chromatography-mass spectrometry (GC-MS. However, this method has various drawbacks, including a high level of contaminations. Thus, we adapted two methods of volatile sampling from other research fields and compared them to sampling with cotton swabs. To do so we assessed the body odor of common marmosets (Callithrix jacchus using cotton swabs, thermal desorption (TD tubes and, alternatively, a mobile GC-MS device containing a thermal desorption trap. Overall, TD tubes comprised most compounds (N = 113, with half of those compounds being volatile (N = 52. The mobile GC-MS captured the fewest compounds (N = 35, of which all were volatile. Cotton swabs contained an intermediate number of compounds (N = 55, but very few volatiles (N = 10. Almost all compounds found with the mobile GC-MS were also captured with TD tubes (94%. Hence, we recommend TD tubes for state of the art sampling of body odor of mammals or other vertebrates, particularly for field studies, as they can be easily transported, stored and analysed with high performance instruments in the lab. Nevertheless, cotton swabs capture compounds which still may contribute to the body odor, e.g. after bacterial fermentation, while profiles from mobile GC-MS include only the most abundant volatiles of the body odor.

Non-uniform sampling and wide range angular spectrum method

International Nuclear Information System (INIS)

Kim, Yong-Hae; Byun, Chun-Won; Oh, Himchan; Lee, JaeWon; Pi, Jae-Eun; Heon Kim, Gi; Lee, Myung-Lae; Ryu, Hojun; Chu, Hye-Yong; Hwang, Chi-Sun

2014-01-01

A novel method is proposed for simulating free space field propagation from a source plane to a destination plane that is applicable for both small and large propagation distances. The angular spectrum method (ASM) was widely used for simulating near field propagation, but it caused a numerical error when the propagation distance was large because of aliasing due to under sampling. Band limited ASM satisfied the Nyquist condition on sampling by limiting a bandwidth of a propagation field to avoid an aliasing error so that it could extend the applicable propagation distance of the ASM. However, the band limited ASM also made an error due to the decrease of an effective sampling number in a Fourier space when the propagation distance was large. In the proposed wide range ASM, we use a non-uniform sampling in a Fourier space to keep a constant effective sampling number even though the propagation distance is large. As a result, the wide range ASM can produce simulation results with high accuracy for both far and near field propagation. For non-paraxial wave propagation, we applied the wide range ASM to a shifted destination plane as well. (paper)

Advanced Markov chain Monte Carlo methods learning from past samples

CERN Document Server

Liang, Faming; Carrol, Raymond J

2010-01-01

This book provides comprehensive coverage of simulation of complex systems using Monte Carlo methods. Developing algorithms that are immune to the local trap problem has long been considered as the most important topic in MCMC research. Various advanced MCMC algorithms which address this problem have been developed include, the modified Gibbs sampler, the methods based on auxiliary variables and the methods making use of past samples. The focus of this book is on the algorithms that make use of past samples. This book includes the multicanonical algorithm, dynamic weighting, dynamically weight

Middle School Girls Sample "Hard Hat" Life at Construction Camp

Science.gov (United States)

Brown, Aneeta

2013-01-01

On a Monday morning in July, a fan as tall as a refrigerator churned noisily in the cavernous classroom. As the outdoor temperature crept higher, teenage girls wearing hardhats and safety glasses wiped perspiration and sawdust from their faces. This was not a field trip. This was the second hour of camp at Ranken Technical College in St. Louis,…

A Novel Analysis Method for Paired-Sample Microbial Ecology Experiments.

Science.gov (United States)

Olesen, Scott W; Vora, Suhani; Techtmann, Stephen M; Fortney, Julian L; Bastidas-Oyanedel, Juan R; Rodríguez, Jorge; Hazen, Terry C; Alm, Eric J

2016-01-01

Many microbial ecology experiments use sequencing data to measure a community's response to an experimental treatment. In a common experimental design, two units, one control and one experimental, are sampled before and after the treatment is applied to the experimental unit. The four resulting samples contain information about the dynamics of organisms that respond to the treatment, but there are no analytical methods designed to extract exactly this type of information from this configuration of samples. Here we present an analytical method specifically designed to visualize and generate hypotheses about microbial community dynamics in experiments that have paired samples and few or no replicates. The method is based on the Poisson lognormal distribution, long studied in macroecology, which we found accurately models the abundance distribution of taxa counts from 16S rRNA surveys. To demonstrate the method's validity and potential, we analyzed an experiment that measured the effect of crude oil on ocean microbial communities in microcosm. Our method identified known oil degraders as well as two clades, Maricurvus and Rhodobacteraceae, that responded to amendment with oil but do not include known oil degraders. Our approach is sensitive to organisms that increased in abundance only in the experimental unit but less sensitive to organisms that increased in both control and experimental units, thus mitigating the role of "bottle effects".

A random spatial sampling method in a rural developing nation

Science.gov (United States)

Michelle C. Kondo; Kent D.W. Bream; Frances K. Barg; Charles C. Branas

2014-01-01

Nonrandom sampling of populations in developing nations has limitations and can inaccurately estimate health phenomena, especially among hard-to-reach populations such as rural residents. However, random sampling of rural populations in developing nations can be challenged by incomplete enumeration of the base population. We describe a stratified random sampling method...

Sampling methods for terrestrial amphibians and reptiles.

Science.gov (United States)

Paul Stephen Corn; R. Bruce. Bury

1990-01-01

Methods described for sampling amphibians and reptiles in Douglas-fir forests in the Pacific Northwest include pitfall trapping, time-constrained collecting, and surveys of coarse woody debris. The herpetofauna of this region differ in breeding and nonbreeding habitats and vagility, so that no single technique is sufficient for a community study. A combination of...

Universal nucleic acids sample preparation method for cells, spores and their mixture

Science.gov (United States)

Bavykin, Sergei [Darien, IL

2011-01-18

The present invention relates to a method for extracting nucleic acids from biological samples. More specifically the invention relates to a universal method for extracting nucleic acids from unidentified biological samples. An advantage of the presently invented method is its ability to effectively and efficiently extract nucleic acids from a variety of different cell types including but not limited to prokaryotic or eukaryotic cells and/or recalcitrant organisms (i.e. spores). Unlike prior art methods which are focused on extracting nucleic acids from vegetative cell or spores, the present invention effectively extracts nucleic acids from spores, multiple cell types or mixtures thereof using a single method. Important that the invented method has demonstrated an ability to extract nucleic acids from spores and vegetative bacterial cells with similar levels effectiveness. The invented method employs a multi-step protocol which erodes the cell structure of the biological sample, isolates, labels, fragments nucleic acids and purifies labeled samples from the excess of dye.

Fluidics platform and method for sample preparation and analysis

Science.gov (United States)

Benner, W. Henry; Dzenitis, John M.; Bennet, William J.; Baker, Brian R.

2014-08-19

Herein provided are fluidics platform and method for sample preparation and analysis. The fluidics platform is capable of analyzing DNA from blood samples using amplification assays such as polymerase-chain-reaction assays and loop-mediated-isothermal-amplification assays. The fluidics platform can also be used for other types of assays and analyzes. In some embodiments, a sample in a sealed tube can be inserted directly. The following isolation, detection, and analyzes can be performed without a user's intervention. The disclosed platform may also comprises a sample preparation system with a magnetic actuator, a heater, and an air-drying mechanism, and fluid manipulation processes for extraction, washing, elution, assay assembly, assay detection, and cleaning after reactions and between samples.

Two media method for linear attenuation coefficient determination of irregular soil samples

International Nuclear Information System (INIS)

Vici, Carlos Henrique Georges

2004-01-01

In several situations of nuclear applications, the knowledge of gamma-ray linear attenuation coefficient for irregular samples is necessary, such as in soil physics and geology. This work presents the validation of a methodology for the determination of the linear attenuation coefficient (μ) of irregular shape samples, in such a way that it is not necessary to know the thickness of the considered sample. With this methodology irregular soil samples (undeformed field samples) from Londrina region, north of Parana were studied. It was employed the two media method for the μ determination. It consists of the μ determination through the measurement of a gamma-ray beam attenuation by the sample sequentially immersed in two different media, with known and appropriately chosen attenuation coefficients. For comparison, the theoretical value of μ was calculated by the product of the mass attenuation coefficient, obtained by the WinXcom code, and the measured value of the density sample. This software employs the chemical composition of the samples and supplies a table of the mass attenuation coefficients versus the photon energy. To verify the validity of the two media method, compared with the simple gamma ray transmission method, regular pome stone samples were used. With these results for the attenuation coefficients and their respective deviations, it was possible to compare the two methods. In this way we concluded that the two media method is a good tool for the determination of the linear attenuation coefficient of irregular materials, particularly in the study of soils samples. (author)

Sampling and examination methods used for TMI-2 samples

International Nuclear Information System (INIS)

Marley, A.W.; Akers, D.W.; McIsaac, C.V.

1988-01-01

The purpose of this paper is to summarize the sampling and examination techniques that were used in the collection and analysis of TMI-2 samples. Samples ranging from auxiliary building air to core debris were collected and analyzed. Handling of the larger samples and many of the smaller samples had to be done remotely and many standard laboratory analytical techniques were modified to accommodate the extremely high radiation fields associated with these samples. The TMI-2 samples presented unique problems with sampling and the laboratory analysis of prior molten fuel debris. 14 refs., 8 figs

[Sample preparation methods for chromatographic analysis of organic components in atmospheric particulate matter].

Science.gov (United States)

Hao, Liang; Wu, Dapeng; Guan, Yafeng

2014-09-01

The determination of organic composition in atmospheric particulate matter (PM) is of great importance in understanding how PM affects human health, environment, climate, and ecosystem. Organic components are also the scientific basis for emission source tracking, PM regulation and risk management. Therefore, the molecular characterization of the organic fraction of PM has become one of the priority research issues in the field of environmental analysis. Due to the extreme complexity of PM samples, chromatographic methods have been the chief selection. The common procedure for the analysis of organic components in PM includes several steps: sample collection on the fiber filters, sample preparation (transform the sample into a form suitable for chromatographic analysis), analysis by chromatographic methods. Among these steps, the sample preparation methods will largely determine the throughput and the data quality. Solvent extraction methods followed by sample pretreatment (e. g. pre-separation, derivatization, pre-concentration) have long been used for PM sample analysis, and thermal desorption methods have also mainly focused on the non-polar organic component analysis in PM. In this paper, the sample preparation methods prior to chromatographic analysis of organic components in PM are reviewed comprehensively, and the corresponding merits and limitations of each method are also briefly discussed.

Sampling methods for amphibians in streams in the Pacific Northwest.

Science.gov (United States)

R. Bruce Bury; Paul Stephen. Corn

1991-01-01

Methods describing how to sample aquatic and semiaquatic amphibians in small streams and headwater habitats in the Pacific Northwest are presented. We developed a technique that samples 10-meter stretches of selected streams, which was adequate to detect presence or absence of amphibian species and provided sample sizes statistically sufficient to compare abundance of...

Evaluation of sampling methods for Bacillus spore-contaminated HVAC filters

OpenAIRE

Calfee, M. Worth; Rose, Laura J.; Tufts, Jenia; Morse, Stephen; Clayton, Matt; Touati, Abderrahmane; Griffin-Gatchalian, Nicole; Slone, Christina; McSweeney, Neal

2013-01-01

The objective of this study was to compare an extraction-based sampling method to two vacuum-based sampling methods (vacuum sock and 37 mm cassette filter) with regards to their ability to recover Bacillus atrophaeus spores (surrogate for Bacillus anthracis) from pleated heating, ventilation, and air conditioning (HVAC) filters that are typically found in commercial and residential buildings. Electrostatic and mechanical HVAC filters were tested, both without and after loading with dust to 50...

Sampling Methods and the Accredited Population in Athletic Training Education Research

Science.gov (United States)

Carr, W. David; Volberding, Jennifer

2009-01-01

Context: We describe methods of sampling the widely-studied, yet poorly defined, population of accredited athletic training education programs (ATEPs). Objective: There are two purposes to this study; first to describe the incidence and types of sampling methods used in athletic training education research, and second to clearly define the…

Method and apparatus for continuous sampling

International Nuclear Information System (INIS)

Marcussen, C.

1982-01-01

An apparatus and method for continuously sampling a pulverous material flow includes means for extracting a representative subflow from a pulverous material flow. A screw conveyor is provided to cause the extracted subflow to be pushed upwardly through a duct to an overflow. Means for transmitting a radiation beam transversely to the subflow in the duct, and means for sensing the transmitted beam through opposite pairs of windows in the duct are provided to measure the concentration of one or more constituents in the subflow. (author)

Sparse feature learning for instrument identification: Effects of sampling and pooling methods.

Science.gov (United States)

Han, Yoonchang; Lee, Subin; Nam, Juhan; Lee, Kyogu

2016-05-01

Feature learning for music applications has recently received considerable attention from many researchers. This paper reports on the sparse feature learning algorithm for musical instrument identification, and in particular, focuses on the effects of the frame sampling techniques for dictionary learning and the pooling methods for feature aggregation. To this end, two frame sampling techniques are examined that are fixed and proportional random sampling. Furthermore, the effect of using onset frame was analyzed for both of proposed sampling methods. Regarding summarization of the feature activation, a standard deviation pooling method is used and compared with the commonly used max- and average-pooling techniques. Using more than 47 000 recordings of 24 instruments from various performers, playing styles, and dynamics, a number of tuning parameters are experimented including the analysis frame size, the dictionary size, and the type of frequency scaling as well as the different sampling and pooling methods. The results show that the combination of proportional sampling and standard deviation pooling achieve the best overall performance of 95.62% while the optimal parameter set varies among the instrument classes.

Active Search on Carcasses versus Pitfall Traps: a Comparison of Sampling Methods.

Science.gov (United States)

Zanetti, N I; Camina, R; Visciarelli, E C; Centeno, N D

2016-04-01

The study of insect succession in cadavers and the classification of arthropods have mostly been done by placing a carcass in a cage, protected from vertebrate scavengers, which is then visited periodically. An alternative is to use specific traps. Few studies on carrion ecology and forensic entomology involving the carcasses of large vertebrates have employed pitfall traps. The aims of this study were to compare both sampling methods (active search on a carcass and pitfall trapping) for each coleopteran family, and to establish whether there is a discrepancy (underestimation and/or overestimation) in the presence of each family by either method. A great discrepancy was found for almost all families with some of them being more abundant in samples obtained through active search on carcasses and others in samples from traps, whereas two families did not show any bias towards a given sampling method. The fact that families may be underestimated or overestimated by the type of sampling technique highlights the importance of combining both methods, active search on carcasses and pitfall traps, in order to obtain more complete information on decomposition, carrion habitat and cadaveric families or species. Furthermore, a hypothesis advanced on the reasons for the underestimation by either sampling method showing biases towards certain families. Information about the sampling techniques indicating which would be more appropriate to detect or find a particular family is provided.

Perilymph sampling from the cochlear apex: a reliable method to obtain higher purity perilymph samples from scala tympani.

Science.gov (United States)

Salt, Alec N; Hale, Shane A; Plonkte, Stefan K R

2006-05-15

Measurements of drug levels in the fluids of the inner ear are required to establish kinetic parameters and to determine the influence of specific local delivery protocols. For most substances, this requires cochlear fluids samples to be obtained for analysis. When auditory function is of primary interest, the drug level in the perilymph of scala tympani (ST) is most relevant, since drug in this scala has ready access to the auditory sensory cells. In many prior studies, ST perilymph samples have been obtained from the basal turn, either by aspiration through the round window membrane (RWM) or through an opening in the bony wall. A number of studies have demonstrated that such samples are likely to be contaminated with cerebrospinal fluid (CSF). CSF enters the basal turn of ST through the cochlear aqueduct when the bony capsule is perforated or when fluid is aspirated. The degree of sample contamination has, however, not been widely appreciated. Recent studies have shown that perilymph samples taken through the round window membrane are highly contaminated with CSF, with samples greater than 2microL in volume containing more CSF than perilymph. In spite of this knowledge, many groups continue to sample from the base of the cochlea, as it is a well-established method. We have developed an alternative, technically simple method to increase the proportion of ST perilymph in a fluid sample. The sample is taken from the apex of the cochlea, a site that is distant from the cochlear aqueduct. A previous problem with sampling through a perforation in the bone was that the native perilymph rapidly leaked out driven by CSF pressure and was lost to the middle ear space. We therefore developed a procedure to collect all the fluid that emerged from the perforated apex after perforation. We evaluated the method using a marker ion trimethylphenylammonium (TMPA). TMPA was applied to the perilymph of guinea pigs either by RW irrigation or by microinjection into the apical turn. The

Survey research with a random digit dial national mobile phone sample in Ghana: Methods and sample quality

Science.gov (United States)

Sefa, Eunice; Adimazoya, Edward Akolgo; Yartey, Emmanuel; Lenzi, Rachel; Tarpo, Cindy; Heward-Mills, Nii Lante; Lew, Katherine; Ampeh, Yvonne

2018-01-01

Introduction Generating a nationally representative sample in low and middle income countries typically requires resource-intensive household level sampling with door-to-door data collection. High mobile phone penetration rates in developing countries provide new opportunities for alternative sampling and data collection methods, but there is limited information about response rates and sample biases in coverage and nonresponse using these methods. We utilized data from an interactive voice response, random-digit dial, national mobile phone survey in Ghana to calculate standardized response rates and assess representativeness of the obtained sample. Materials and methods The survey methodology was piloted in two rounds of data collection. The final survey included 18 demographic, media exposure, and health behavior questions. Call outcomes and response rates were calculated according to the American Association of Public Opinion Research guidelines. Sample characteristics, productivity, and costs per interview were calculated. Representativeness was assessed by comparing data to the Ghana Demographic and Health Survey and the National Population and Housing Census. Results The survey was fielded during a 27-day period in February-March 2017. There were 9,469 completed interviews and 3,547 partial interviews. Response, cooperation, refusal, and contact rates were 31%, 81%, 7%, and 39% respectively. Twenty-three calls were dialed to produce an eligible contact: nonresponse was substantial due to the automated calling system and dialing of many unassigned or non-working numbers. Younger, urban, better educated, and male respondents were overrepresented in the sample. Conclusions The innovative mobile phone data collection methodology yielded a large sample in a relatively short period. Response rates were comparable to other surveys, although substantial coverage bias resulted from fewer women, rural, and older residents completing the mobile phone survey in

A Mixed Methods Sampling Methodology for a Multisite Case Study

Science.gov (United States)

Sharp, Julia L.; Mobley, Catherine; Hammond, Cathy; Withington, Cairen; Drew, Sam; Stringfield, Sam; Stipanovic, Natalie

2012-01-01

The flexibility of mixed methods research strategies makes such approaches especially suitable for multisite case studies. Yet the utilization of mixed methods to select sites for these studies is rarely reported. The authors describe their pragmatic mixed methods approach to select a sample for their multisite mixed methods case study of a…

[Standard sample preparation method for quick determination of trace elements in plastic].

Science.gov (United States)

Yao, Wen-Qing; Zong, Rui-Long; Zhu, Yong-Fa

2011-08-01

Reference sample was prepared by masterbatch method, containing heavy metals with known concentration of electronic information products (plastic), the repeatability and precision were determined, and reference sample preparation procedures were established. X-Ray fluorescence spectroscopy (XRF) analysis method was used to determine the repeatability and uncertainty in the analysis of the sample of heavy metals and bromine element. The working curve and the metrical methods for the reference sample were carried out. The results showed that the use of the method in the 200-2000 mg x kg(-1) concentration range for Hg, Pb, Cr and Br elements, and in the 20-200 mg x kg(-1) range for Cd elements, exhibited a very good linear relationship, and the repeatability of analysis methods for six times is good. In testing the circuit board ICB288G and ICB288 from the Mitsubishi Heavy Industry Company, results agreed with the recommended values.

Evaluation of sampling methods for the detection of Salmonella in broiler flocks

DEFF Research Database (Denmark)

Skov, Marianne N.; Carstensen, B.; Tornoe, N.

1999-01-01

The present study compares four different sampling methods potentially applicable to detection of Salmonella in broiler flocks, based on collection of faecal samples (i) by hand, 300 fresh faecal samples (ii) absorbed on five sheets of paper (iii) absorbed on five pairs of socks (elastic cotton...... horizontal or vertical) were found in the investigation. The results showed that the sock method (five pairs of socks) had a sensitivity comparable with the hand collection method (60 pools of five faecal samples); the paper collection method was inferior, as was the use of only one pair of socks, Estimation...... tubes pulled over the boots and termed 'socks') and (iv) by using only one pair of socks. Twenty-three broiler flocks were included in the investigation and 18 of these were found to be positive by at least one method. Seven serotypes of Salmonella with different patterns of transmission (mainly...

Phylogenetic representativeness: a new method for evaluating taxon sampling in evolutionary studies

Directory of Open Access Journals (Sweden)

Passamonti Marco

2010-04-01

Full Text Available Abstract Background Taxon sampling is a major concern in phylogenetic studies. Incomplete, biased, or improper taxon sampling can lead to misleading results in reconstructing evolutionary relationships. Several theoretical methods are available to optimize taxon choice in phylogenetic analyses. However, most involve some knowledge about the genetic relationships of the group of interest (i.e., the ingroup, or even a well-established phylogeny itself; these data are not always available in general phylogenetic applications. Results We propose a new method to assess taxon sampling developing Clarke and Warwick statistics. This method aims to measure the "phylogenetic representativeness" of a given sample or set of samples and it is based entirely on the pre-existing available taxonomy of the ingroup, which is commonly known to investigators. Moreover, our method also accounts for instability and discordance in taxonomies. A Python-based script suite, called PhyRe, has been developed to implement all analyses we describe in this paper. Conclusions We show that this method is sensitive and allows direct discrimination between representative and unrepresentative samples. It is also informative about the addition of taxa to improve taxonomic coverage of the ingroup. Provided that the investigators' expertise is mandatory in this field, phylogenetic representativeness makes up an objective touchstone in planning phylogenetic studies.

Enhanced Sampling in Free Energy Calculations: Combining SGLD with the Bennett's Acceptance Ratio and Enveloping Distribution Sampling Methods.

Science.gov (United States)

König, Gerhard; Miller, Benjamin T; Boresch, Stefan; Wu, Xiongwu; Brooks, Bernard R

2012-10-09

One of the key requirements for the accurate calculation of free energy differences is proper sampling of conformational space. Especially in biological applications, molecular dynamics simulations are often confronted with rugged energy surfaces and high energy barriers, leading to insufficient sampling and, in turn, poor convergence of the free energy results. In this work, we address this problem by employing enhanced sampling methods. We explore the possibility of using self-guided Langevin dynamics (SGLD) to speed up the exploration process in free energy simulations. To obtain improved free energy differences from such simulations, it is necessary to account for the effects of the bias due to the guiding forces. We demonstrate how this can be accomplished for the Bennett's acceptance ratio (BAR) and the enveloping distribution sampling (EDS) methods. While BAR is considered among the most efficient methods available for free energy calculations, the EDS method developed by Christ and van Gunsteren is a promising development that reduces the computational costs of free energy calculations by simulating a single reference state. To evaluate the accuracy of both approaches in connection with enhanced sampling, EDS was implemented in CHARMM. For testing, we employ benchmark systems with analytical reference results and the mutation of alanine to serine. We find that SGLD with reweighting can provide accurate results for BAR and EDS where conventional molecular dynamics simulations fail. In addition, we compare the performance of EDS with other free energy methods. We briefly discuss the implications of our results and provide practical guidelines for conducting free energy simulations with SGLD.

Some refinements on the comparison of areal sampling methods via simulation

Science.gov (United States)

Jeffrey Gove

2017-01-01

The design of forest inventories and development of new sampling methods useful in such inventories normally have a two-fold target of design unbiasedness and minimum variance in mind. Many considerations such as costs go into the choices of sampling method for operational and other levels of inventory. However, the variance in terms of meeting a specified level of...

Preparation Of Deposited Sediment Sample By Casting Method For Environmental Study

International Nuclear Information System (INIS)

Hutabarat, Tommy; Ristin PI, Evarista

2000-01-01

The preparation of deposited sediment sample by c asting m ethod for environmental study has been carried out. This method comprises separation of size fraction and casting process. The deposited sediment samples were wet sieved to separate the size fraction of >500 mum, (250-500) mum, (125-250) mum and (63-125) mum and settling procedures were followed for the separation of (40-63) mum, (20-40) mum, (10-20) mum and o C, ashed at 450 o C, respectively. In the casting process of sample, it was used polyester rapid cure resin and methyl ethyl ketone peroxide (MEKP) hardener. The moulded sediment sample was poured onto caster, allow for 60 hours long. The aim of this method is to get the casted sample which can be used effectively, efficiently and to be avoided from contamination of each other samples. Before casting, samples were grinded up to be fine. The result shows that casting product is ready to be used for natural radionuclide analysis

Global metabolite analysis of yeast: evaluation of sample preparation methods

DEFF Research Database (Denmark)

Villas-Bôas, Silas Granato; Højer-Pedersen, Jesper; Åkesson, Mats Fredrik

2005-01-01

Sample preparation is considered one of the limiting steps in microbial metabolome analysis. Eukaryotes and prokaryotes behave very differently during the several steps of classical sample preparation methods for analysis of metabolites. Even within the eukaryote kingdom there is a vast diversity...

Comparison of four sampling methods for the detection of Salmonella in broiler litter.

Science.gov (United States)

Buhr, R J; Richardson, L J; Cason, J A; Cox, N A; Fairchild, B D

2007-01-01

Experiments were conducted to compare litter sampling methods for the detection of Salmonella. In experiment 1, chicks were challenged orally with a suspension of naladixic acid-resistant Salmonella and wing banded, and additional nonchallenged chicks were placed into each of 2 challenge pens. Nonchallenged chicks were placed into each nonchallenge pen located adjacent to the challenge pens. At 7, 8, 10, and 11 wk of age the litter was sampled using 4 methods: fecal droppings, litter grab, drag swab, and sock. For the challenge pens, Salmonella-positive samples were detected in 3 of 16 fecal samples, 6 of 16 litter grab samples, 7 of 16 drag swabs samples, and 7 of 16 sock samples. Samples from the nonchallenge pens were Salmonella positive in 2 of 16 litter grab samples, 9 of 16 drag swab samples, and 9 of 16 sock samples. In experiment 2, chicks were challenged with Salmonella, and the litter in the challenge and adjacent nonchallenge pens were sampled at 4, 6, and 8 wk of age with broilers remaining in all pens. For the challenge pens, Salmonella was detected in 10 of 36 fecal samples, 20 of 36 litter grab samples, 14 of 36 drag swab samples, and 26 of 36 sock samples. Samples from the adjacent nonchallenge pens were positive for Salmonella in 6 of 36 fecal droppings samples, 4 of 36 litter grab samples, 7 of 36 drag swab samples, and 19 of 36 sock samples. Sock samples had the highest rates of Salmonella detection. In experiment 3, the litter from a Salmonella-challenged flock was sampled at 7, 8, and 9 wk by socks and drag swabs. In addition, comparisons with drag swabs that were stepped on during sampling were made. Both socks (24 of 36, 67%) and drag swabs that were stepped on (25 of 36, 69%) showed significantly more Salmonella-positive samples than the traditional drag swab method (16 of 36, 44%). Drag swabs that were stepped on had comparable Salmonella detection level to that for socks. Litter sampling methods that incorporate stepping on the sample

On the Exploitation of Sensitivity Derivatives for Improving Sampling Methods

Science.gov (United States)

Cao, Yanzhao; Hussaini, M. Yousuff; Zang, Thomas A.

2003-01-01

Many application codes, such as finite-element structural analyses and computational fluid dynamics codes, are capable of producing many sensitivity derivatives at a small fraction of the cost of the underlying analysis. This paper describes a simple variance reduction method that exploits such inexpensive sensitivity derivatives to increase the accuracy of sampling methods. Three examples, including a finite-element structural analysis of an aircraft wing, are provided that illustrate an order of magnitude improvement in accuracy for both Monte Carlo and stratified sampling schemes.

The study of combining Latin Hypercube Sampling method and LU decomposition method (LULHS method) for constructing spatial random field

Science.gov (United States)

WANG, P. T.

2015-12-01

Groundwater modeling requires to assign hydrogeological properties to every numerical grid. Due to the lack of detailed information and the inherent spatial heterogeneity, geological properties can be treated as random variables. Hydrogeological property is assumed to be a multivariate distribution with spatial correlations. By sampling random numbers from a given statistical distribution and assigning a value to each grid, a random field for modeling can be completed. Therefore, statistics sampling plays an important role in the efficiency of modeling procedure. Latin Hypercube Sampling (LHS) is a stratified random sampling procedure that provides an efficient way to sample variables from their multivariate distributions. This study combines the the stratified random procedure from LHS and the simulation by using LU decomposition to form LULHS. Both conditional and unconditional simulations of LULHS were develpoed. The simulation efficiency and spatial correlation of LULHS are compared to the other three different simulation methods. The results show that for the conditional simulation and unconditional simulation, LULHS method is more efficient in terms of computational effort. Less realizations are required to achieve the required statistical accuracy and spatial correlation.

System for Packaging Planetary Samples for Return to Earth

Science.gov (United States)

Badescu, Mircea; Bar-Cohen, Yoseph; Backes, paul G.; Sherrit, Stewart; Bao, Xiaoqi; Scott, James S.

2010-01-01

A system is proposed for packaging material samples on a remote planet (especially Mars) in sealed sample tubes in preparation for later return to Earth. The sample tubes (Figure 1) would comprise (1) tubes initially having open tops and closed bottoms; (2) small, bellows-like collapsible bodies inside the tubes at their bottoms; and (3) plugs to be eventually used to close the tops of the tubes. The top inner surface of each tube would be coated with solder. The side of each plug, which would fit snugly into a tube, would feature a solder-filled ring groove. The system would include equipment for storing, manipulating, filling, and sealing the tubes. The containerization system (see Figure 2) will be organized in stations and will include: the storage station, the loading station, and the heating station. These stations can be structured in circular or linear pattern to minimize the manipulator complexity, allowing for compact design and mass efficiency. The manipulation of the sample tube between stations is done by a simple manipulator arm. The storage station contains the unloaded sample tubes and the plugs before sealing as well as the sealed sample tubes with samples after loading and sealing. The chambers at the storage station also allow for plug insertion into the sample tube. At the loading station the sample is poured or inserted into the sample tube and then the tube is topped off. At the heating station the plug is heated so the solder ring melts and seals the plug to the sample tube. The process is performed as follows: Each tube is filled or slightly overfilled with sample material and the excess sample material is wiped off the top. Then, the plug is inserted into the top section of the tube packing the sample material against the collapsible bellowslike body allowing the accommodation of the sample volume. The plug and the top of the tube are heated momentarily to melt the solder in order to seal the tube.

The method of Sample Management in Neutron Activation Analysis Laboratory-Serpong

International Nuclear Information System (INIS)

Elisabeth-Ratnawati

2005-01-01

In the testing laboratory used by neutron activation analysis method, sample preparation is the main factor and it can't be neglect. The error in the sample preparation can give result with lower accuracy. In this article is explained the scheme of sample preparation i.e sample receive administration, the separate of sample, fluid and solid sample preparation, sample grouping, irradiation, sample counting and holding the sample post irradiation. If the management of samples were good application based on Standard Operation Procedure, therefore each samples has good traceability. To optimize the management of samples is needed the trained and skilled personal and good facility. (author)

Assessment of Progressive Product Innovation on Key Environmental Indicators: Pampers® Baby Wipes from 2007–2013

Directory of Open Access Journals (Sweden)

Gert Van Hoof

2014-08-01

Full Text Available Companies are increasingly conducting life cycle assessments (LCA of their products to understand potential product impacts on the environment, prioritize areas of innovation to create more sustainable products, and determine valid claims. This case study shows the results of product innovation by comparing an older (2007 and new (2013 version of a common hygiene product in Europe and the U.S. The standard methodology follows the ISO 14040/44 Guidelines for LCA. Results are reported for the impact indicators with high relevance for the product category: primary energy, global warming, particulates, agricultural land occupation, fossil fuel depletion, and solid waste generation. Generally, raw material supply chains for product and packaging contribute most (up to 82% to the calculated environmental impact indicators. Improvements vs. the 2007 baby wipe range between 4% and 14% in Europe and between 15% and 36% in the U.S. The improvement is driven by a new substrate technology that provides more surface area for cleaning, which results in lower use of resources. This case study illustrates three key environmental drivers behind this innovation: the corporate focus on R&D capability to design for environmentally improved products, the increased interest from retailers and consumers requiring accurate and relevant information on the performance and sustainability of products, and the company’s interest in deeper technical understanding of contributions from upstream material and process innovations on a product’s environmental profile.

222Rn in water: A comparison of two sample collection methods and two sample transport methods, and the determination of temporal variation in North Carolina ground water

International Nuclear Information System (INIS)

Hightower, J.H. III

1994-01-01

Objectives of this field experiment were: (1) determine whether there was a statistically significant difference between the radon concentrations of samples collected by EPA's standard method, using a syringe, and an alternative, slow-flow method; (2) determine whether there was a statistically significant difference between the measured radon concentrations of samples mailed vs samples not mailed; and (3) determine whether there was a temporal variation of water radon concentration over a 7-month period. The field experiment was conducted at 9 sites, 5 private wells, and 4 public wells, at various locations in North Carolina. Results showed that a syringe is not necessary for sample collection, there was generally no significant radon loss due to mailing samples, and there was statistically significant evidence of temporal variations in water radon concentrations

[DOE method for evaluating environmental and waste management samples: Revision 1, Addendum 1

Energy Technology Data Exchange (ETDEWEB)

Goheen, S.C.

1995-04-01

The US Dapartment of Energy`s (DOE`s) environmental and waste management (EM) sampling and analysis activities require that large numbers of samples be analyzed for materials characterization, environmental surveillance, and site-remediation programs. The present document, DOE Methods for Evaluating Environmental and Waste Management Samples (DOE Methods), is a supplemental resource for analyzing many of these samples.

[DOE method for evaluating environmental and waste management samples: Revision 1, Addendum 1

International Nuclear Information System (INIS)

Goheen, S.C.

1995-04-01

The US Dapartment of Energy's (DOE's) environmental and waste management (EM) sampling and analysis activities require that large numbers of samples be analyzed for materials characterization, environmental surveillance, and site-remediation programs. The present document, DOE Methods for Evaluating Environmental and Waste Management Samples (DOE Methods), is a supplemental resource for analyzing many of these samples

Development of sample preparation method for honey analysis using PIXE

International Nuclear Information System (INIS)

Saitoh, Katsumi; Chiba, Keiko; Sera, Koichiro

2008-01-01

We developed an original preparation method for honey samples (samples in paste-like state) specifically designed for PIXE analysis. The results of PIXE analysis of thin targets prepared by adding a standard containing nine elements to honey samples demonstrated that the preparation method bestowed sufficient accuracy on quantitative values. PIXE analysis of 13 kinds of honey was performed, and eight mineral components (Si, P, S, K, Ca, Mn, Cu and Zn) were detected in all honey samples. The principal mineral components were K and Ca, and the quantitative value for K accounted for the majority of the total value for mineral components. K content in honey varies greatly depending on the plant source. Chestnuts had the highest K content. In fact, it was 2-3 times that of Manuka, which is known as a high quality honey. K content of false-acacia, which is produced in the greatest abundance, was 1/20 that of chestnuts. (author)

Method of separate determination of high-ohmic sample resistance and contact resistance

Directory of Open Access Journals (Sweden)

Vadim A. Golubiatnikov

2015-09-01

Full Text Available A method of separate determination of two-pole sample volume resistance and contact resistance is suggested. The method is applicable to high-ohmic semiconductor samples: semi-insulating gallium arsenide, detector cadmium-zinc telluride (CZT, etc. The method is based on near-contact region illumination by monochromatic radiation of variable intensity from light emitting diodes with quantum energies exceeding the band gap of the material. It is necessary to obtain sample photo-current dependence upon light emitting diode current and to find the linear portion of this dependence. Extrapolation of this linear portion to the Y-axis gives the cut-off current. As the bias voltage is known, it is easy to calculate sample volume resistance. Then, using dark current value, one can determine the total contact resistance. The method was tested for n-type semi-insulating GaAs. The contact resistance value was shown to be approximately equal to the sample volume resistance. Thus, the influence of contacts must be taken into account when electrophysical data are analyzed.

Method validation to determine total alpha beta emitters in water samples using LSC

International Nuclear Information System (INIS)

Al-Masri, M. S.; Nashawati, A.; Al-akel, B.; Saaid, S.

2006-06-01

In this work a method was validated to determine gross alpha and beta emitters in water samples using liquid scintillation counter. 200 ml of water from each sample were evaporated to 20 ml and 8 ml of them were mixed with 12 ml of the suitable cocktail to be measured by liquid scintillation counter Wallac Winspectral 1414. The lower detection limit by this method (LDL) was 0.33 DPM for total alpha emitters and 1.3 DPM for total beta emitters. and the reproducibility limit was (± 2.32 DPM) and (±1.41 DPM) for total alpha and beta emitters respectively, and the repeatability limit was (±2.19 DPM) and (±1.11 DPM) for total alpha and beta emitters respectively. The method is easy and fast because of the simple preparation steps and the large number of samples that can be measured at the same time. In addition, many real samples and standard samples were analyzed by the method and showed accurate results so it was concluded that the method can be used with various water samples. (author)

Coupling methods for multistage sampling

OpenAIRE

Chauvet, Guillaume

2015-01-01

Multistage sampling is commonly used for household surveys when there exists no sampling frame, or when the population is scattered over a wide area. Multistage sampling usually introduces a complex dependence in the selection of the final units, which makes asymptotic results quite difficult to prove. In this work, we consider multistage sampling with simple random without replacement sampling at the first stage, and with an arbitrary sampling design for further stages. We consider coupling ...

An improved correlated sampling method for calculating correction factor of detector

International Nuclear Information System (INIS)

Wu Zhen; Li Junli; Cheng Jianping

2006-01-01

In the case of a small size detector lying inside a bulk of medium, there are two problems in the correction factors calculation of the detectors. One is that the detector is too small for the particles to arrive at and collide in; the other is that the ratio of two quantities is not accurate enough. The method discussed in this paper, which combines correlated sampling with modified particle collision auto-importance sampling, and has been realized on the MCNP-4C platform, can solve these two problems. Besides, other 3 variance reduction techniques are also combined with correlated sampling respectively to calculate a simple calculating model of the correction factors of detectors. The results prove that, although all the variance reduction techniques combined with correlated sampling can improve the calculating efficiency, the method combining the modified particle collision auto-importance sampling with the correlated sampling is the most efficient one. (authors)

Standard methods for sampling freshwater fishes: Opportunities for international collaboration

Science.gov (United States)

Bonar, Scott A.; Mercado-Silva, Norman; Hubert, Wayne A.; Beard, Douglas; Dave, Göran; Kubečka, Jan; Graeb, Brian D. S.; Lester, Nigel P.; Porath, Mark T.; Winfield, Ian J.

2017-01-01

With publication of Standard Methods for Sampling North American Freshwater Fishes in 2009, the American Fisheries Society (AFS) recommended standard procedures for North America. To explore interest in standardizing at intercontinental scales, a symposium attended by international specialists in freshwater fish sampling was convened at the 145th Annual AFS Meeting in Portland, Oregon, in August 2015. Participants represented all continents except Australia and Antarctica and were employed by state and federal agencies, universities, nongovernmental organizations, and consulting businesses. Currently, standardization is practiced mostly in North America and Europe. Participants described how standardization has been important for management of long-term data sets, promoting fundamental scientific understanding, and assessing efficacy of large spatial scale management strategies. Academics indicated that standardization has been useful in fisheries education because time previously used to teach how sampling methods are developed is now more devoted to diagnosis and treatment of problem fish communities. Researchers reported that standardization allowed increased sample size for method validation and calibration. Group consensus was to retain continental standards where they currently exist but to further explore international and intercontinental standardization, specifically identifying where synergies and bridges exist, and identify means to collaborate with scientists where standardization is limited but interest and need occur.

Sampling methods for the study of pneumococcal carriage: a systematic review.

Science.gov (United States)

Gladstone, R A; Jefferies, J M; Faust, S N; Clarke, S C

2012-11-06

Streptococcus pneumoniae is an important pathogen worldwide. Accurate sampling of S. pneumoniae carriage is central to surveillance studies before and following conjugate vaccination programmes to combat pneumococcal disease. Any bias introduced during sampling will affect downstream recovery and typing. Many variables exist for the method of collection and initial processing, which can make inter-laboratory or international comparisons of data complex. In February 2003, a World Health Organisation working group published a standard method for the detection of pneumococcal carriage for vaccine trials to reduce or eliminate variability. We sought to describe the variables associated with the sampling of S. pneumoniae from collection to storage in the context of the methods recommended by the WHO and those used in pneumococcal carriage studies since its publication. A search of published literature in the online PubMed database was performed on the 1st June 2012, to identify published studies that collected pneumococcal carriage isolates, conducted after the publication of the WHO standard method. After undertaking a systematic analysis of the literature, we show that a number of differences in pneumococcal sampling protocol continue to exist between studies since the WHO publication. The majority of studies sample from the nasopharynx, but the choice of swab and swab transport media is more variable between studies. At present there is insufficient experimental data that supports the optimal sensitivity of any standard method. This may have contributed to incomplete adoption of the primary stages of the WHO detection protocol, alongside pragmatic or logistical issues associated with study design. Consequently studies may not provide a true estimate of pneumococcal carriage. Optimal sampling of carriage could lead to improvements in downstream analysis and the evaluation of pneumococcal vaccine impact and extrapolation to pneumococcal disease control therefore

A faster sample preparation method for determination of polonium-210 in fish

International Nuclear Information System (INIS)

Sadi, B.B.; Jing Chen; Kochermin, Vera; Godwin Tung; Sorina Chiorean

2016-01-01

In order to facilitate Health Canada’s study on background radiation levels in country foods, an in-house radio-analytical method has been developed for determination of polonium-210 ( 210 Po) in fish samples. The method was validated by measurement of 210 Po in a certified reference material. It was also evaluated by comparing 210 Po concentrations in a number of fish samples by another method. The in-house method offers faster sample dissolution using an automated digestion system compared to currently used wet-ashing on a hot plate. It also utilizes pre-packed Sr-resin® cartridges for rapid and reproducible separation of 210 Po versus time-consuming manually packed Sr-resin® columns. (author)

Comparison of DNA preservation methods for environmental bacterial community samples.

Science.gov (United States)

Gray, Michael A; Pratte, Zoe A; Kellogg, Christina A

2013-02-01

Field collections of environmental samples, for example corals, for molecular microbial analyses present distinct challenges. The lack of laboratory facilities in remote locations is common, and preservation of microbial community DNA for later study is critical. A particular challenge is keeping samples frozen in transit. Five nucleic acid preservation methods that do not require cold storage were compared for effectiveness over time and ease of use. Mixed microbial communities of known composition were created and preserved by DNAgard(™), RNAlater(®), DMSO-EDTA-salt (DESS), FTA(®) cards, and FTA Elute(®) cards. Automated ribosomal intergenic spacer analysis and clone libraries were used to detect specific changes in the faux communities over weeks and months of storage. A previously known bias in FTA(®) cards that results in lower recovery of pure cultures of Gram-positive bacteria was also detected in mixed community samples. There appears to be a uniform bias across all five preservation methods against microorganisms with high G + C DNA. Overall, the liquid-based preservatives (DNAgard(™), RNAlater(®), and DESS) outperformed the card-based methods. No single liquid method clearly outperformed the others, leaving method choice to be based on experimental design, field facilities, shipping constraints, and allowable cost. © 2012 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

Probability Sampling Method for a Hidden Population Using Respondent-Driven Sampling: Simulation for Cancer Survivors.

Science.gov (United States)

Jung, Minsoo

2015-01-01

When there is no sampling frame within a certain group or the group is concerned that making its population public would bring social stigma, we say the population is hidden. It is difficult to approach this kind of population survey-methodologically because the response rate is low and its members are not quite honest with their responses when probability sampling is used. The only alternative known to address the problems caused by previous methods such as snowball sampling is respondent-driven sampling (RDS), which was developed by Heckathorn and his colleagues. RDS is based on a Markov chain, and uses the social network information of the respondent. This characteristic allows for probability sampling when we survey a hidden population. We verified through computer simulation whether RDS can be used on a hidden population of cancer survivors. According to the simulation results of this thesis, the chain-referral sampling of RDS tends to minimize as the sample gets bigger, and it becomes stabilized as the wave progresses. Therefore, it shows that the final sample information can be completely independent from the initial seeds if a certain level of sample size is secured even if the initial seeds were selected through convenient sampling. Thus, RDS can be considered as an alternative which can improve upon both key informant sampling and ethnographic surveys, and it needs to be utilized for various cases domestically as well.

OPTIMAL METHOD FOR PREPARATION OF SILICATE ROCK SAMPLES FOR ANALYTICAL PURPOSES

Directory of Open Access Journals (Sweden)

Maja Vrkljan

2004-12-01

Full Text Available The purpose of this study was to determine an optimal dissolution method for silicate rock samples for further analytical purposes. Analytical FAAS method of determining cobalt, chromium, copper, nickel, lead and zinc content in gabbro sample and geochemical standard AGV-1 has been applied for verification. Dissolution in mixtures of various inorganic acids has been tested, as well as Na2CO3 fusion technique. The results obtained by different methods have been compared and dissolution in the mixture of HNO3 + HF has been recommended as optimal.

A generalized transmission method for gamma-efficiency determinations in soil samples

International Nuclear Information System (INIS)

Bolivar, J.P.; Garcia-Tenorio, R.; Garcia-Leon, M.

1994-01-01

In this paper, a generalization of the γ-ray transmission method which is useful for measurements on soil samples, for example, is presented. The correction factor, f, is given, which is a function of the apparent density of the soil and the γ-ray energy. With this method, the need for individual determinations of f, for each energy and apparent soil density is avoided. Although the method has been developed for soils, the general philosophy can be applied to other sample matrices, such as water or vegetables for example. (author)

Rock sampling. [method for controlling particle size distribution

Science.gov (United States)

Blum, P. (Inventor)

1971-01-01

A method for sampling rock and other brittle materials and for controlling resultant particle sizes is described. The method involves cutting grooves in the rock surface to provide a grouping of parallel ridges and subsequently machining the ridges to provide a powder specimen. The machining step may comprise milling, drilling, lathe cutting or the like; but a planing step is advantageous. Control of the particle size distribution is effected primarily by changing the height and width of these ridges. This control exceeds that obtainable by conventional grinding.

Interval estimation methods of the mean in small sample situation and the results' comparison

International Nuclear Information System (INIS)

Wu Changli; Guo Chunying; Jiang Meng; Lin Yuangen

2009-01-01

The methods of the sample mean's interval estimation, namely the classical method, the Bootstrap method, the Bayesian Bootstrap method, the Jackknife method and the spread method of the Empirical Characteristic distribution function are described. Numerical calculation on the samples' mean intervals is carried out where the numbers of the samples are 4, 5, 6 respectively. The results indicate the Bootstrap method and the Bayesian Bootstrap method are much more appropriate than others in small sample situation. (authors)

Security of patient data when decommissioning ultrasound systems.

Science.gov (United States)

Moggridge, James

2017-02-01

Although ultrasound systems generally archive to Picture Archiving and Communication Systems (PACS), their archiving workflow typically involves storage to an internal hard disk before data are transferred onwards. Deleting records from the local system will delete entries in the database and from the file allocation table or equivalent but, as with a PC, files can be recovered. Great care is taken with disposal of media from a healthcare organisation to prevent data breaches, but ultrasound systems are routinely returned to lease companies, sold on or donated to third parties without such controls. In this project, five methods of hard disk erasure were tested on nine ultrasound systems being decommissioned: the system's own delete function; full reinstallation of system software; the manufacturer's own disk wiping service; open source disk wiping software for full and just blank space erasure. Attempts were then made to recover data using open source recovery tools. All methods deleted patient data as viewable from the ultrasound system and from browsing the disk from a PC. However, patient identifiable data (PID) could be recovered following the system's own deletion and the reinstallation methods. No PID could be recovered after using the manufacturer's wiping service or the open source wiping software. The typical method of reinstalling an ultrasound system's software may not prevent PID from being recovered. When transferring ownership, care should be taken that an ultrasound system's hard disk has been wiped to a sufficient level, particularly if the scanner is to be returned with approved parts and in a fully working state.

Validation of curve-fitting method for blood retention of 99mTc-GSA. Comparison with blood sampling method

International Nuclear Information System (INIS)

Ha-Kawa, Sang Kil; Suga, Yutaka; Kouda, Katsuyasu; Ikeda, Koshi; Tanaka, Yoshimasa

1997-01-01

We investigated a curve-fitting method for the rate of blood retention of 99m Tc-galactosyl serum albumin (GSA) as a substitute for the blood sampling method. Seven healthy volunteers and 27 patients with liver disease underwent 99m Tc-GSA scanning. After normalization of the y-intercept as 100 percent, a biexponential regression curve for the precordial time-activity curve provided the percent injected dose (%ID) of 99m Tc-GSA in the blood without blood sampling. The discrepancy between %ID obtained by the curve-fitting method and that by the multiple blood samples was minimal in normal volunteers 3.1±2.1% (mean±standard deviation, n=77 sampling). Slightly greater discrepancy was observed in patients with liver disease (7.5±6.1%, n=135 sampling). The %ID at 15 min after injection obtained from the fitted curve was significantly greater in patients with liver cirrhosis than in the controls (53.2±11.6%, n=13; vs. 31.9±2.8%, n=7, p 99m Tc-GSA and the plasma retention rate for indocyanine green (r=-0.869, p 99m Tc-GSA and could be a substitute for the blood sampling method. (author)

Simulated Tempering Distributed Replica Sampling, Virtual Replica Exchange, and Other Generalized-Ensemble Methods for Conformational Sampling.

Science.gov (United States)

Rauscher, Sarah; Neale, Chris; Pomès, Régis

2009-10-13

Generalized-ensemble algorithms in temperature space have become popular tools to enhance conformational sampling in biomolecular simulations. A random walk in temperature leads to a corresponding random walk in potential energy, which can be used to cross over energetic barriers and overcome the problem of quasi-nonergodicity. In this paper, we introduce two novel methods: simulated tempering distributed replica sampling (STDR) and virtual replica exchange (VREX). These methods are designed to address the practical issues inherent in the replica exchange (RE), simulated tempering (ST), and serial replica exchange (SREM) algorithms. RE requires a large, dedicated, and homogeneous cluster of CPUs to function efficiently when applied to complex systems. ST and SREM both have the drawback of requiring extensive initial simulations, possibly adaptive, for the calculation of weight factors or potential energy distribution functions. STDR and VREX alleviate the need for lengthy initial simulations, and for synchronization and extensive communication between replicas. Both methods are therefore suitable for distributed or heterogeneous computing platforms. We perform an objective comparison of all five algorithms in terms of both implementation issues and sampling efficiency. We use disordered peptides in explicit water as test systems, for a total simulation time of over 42 μs. Efficiency is defined in terms of both structural convergence and temperature diffusion, and we show that these definitions of efficiency are in fact correlated. Importantly, we find that ST-based methods exhibit faster temperature diffusion and correspondingly faster convergence of structural properties compared to RE-based methods. Within the RE-based methods, VREX is superior to both SREM and RE. On the basis of our observations, we conclude that ST is ideal for simple systems, while STDR is well-suited for complex systems.

Evaluation of the point-centred-quarter method of sampling ...

African Journals Online (AJOL)

-quarter method.The parameter which was most efficiently sampled was species composition relativedensity) with 90% replicate similarity being achieved with 100 point-centred-quarters. However, this technique cannot be recommended, even ...

An Optimized Method for Quantification of Pathogenic Leptospira in Environmental Water Samples.

Science.gov (United States)

Riediger, Irina N; Hoffmaster, Alex R; Casanovas-Massana, Arnau; Biondo, Alexander W; Ko, Albert I; Stoddard, Robyn A

2016-01-01

Leptospirosis is a zoonotic disease usually acquired by contact with water contaminated with urine of infected animals. However, few molecular methods have been used to monitor or quantify pathogenic Leptospira in environmental water samples. Here we optimized a DNA extraction method for the quantification of leptospires using a previously described Taqman-based qPCR method targeting lipL32, a gene unique to and highly conserved in pathogenic Leptospira. QIAamp DNA mini, MO BIO PowerWater DNA and PowerSoil DNA Isolation kits were evaluated to extract DNA from sewage, pond, river and ultrapure water samples spiked with leptospires. Performance of each kit varied with sample type. Sample processing methods were further evaluated and optimized using the PowerSoil DNA kit due to its performance on turbid water samples and reproducibility. Centrifugation speeds, water volumes and use of Escherichia coli as a carrier were compared to improve DNA recovery. All matrices showed a strong linearity in a range of concentrations from 106 to 10° leptospires/mL and lower limits of detection ranging from Leptospira in environmental waters (river, pond and sewage) which consists of the concentration of 40 mL samples by centrifugation at 15,000×g for 20 minutes at 4°C, followed by DNA extraction with the PowerSoil DNA Isolation kit. Although the method described herein needs to be validated in environmental studies, it potentially provides the opportunity for effective, timely and sensitive assessment of environmental leptospiral burden.

A self-sampling method to obtain large volumes of undiluted cervicovaginal secretions.

Science.gov (United States)

Boskey, Elizabeth R; Moench, Thomas R; Hees, Paul S; Cone, Richard A

2003-02-01

Studies of vaginal physiology and pathophysiology sometime require larger volumes of undiluted cervicovaginal secretions than can be obtained by current methods. A convenient method for self-sampling these secretions outside a clinical setting can facilitate such studies of reproductive health. The goal was to develop a vaginal self-sampling method for collecting large volumes of undiluted cervicovaginal secretions. A menstrual collection device (the Instead cup) was inserted briefly into the vagina to collect secretions that were then retrieved from the cup by centrifugation in a 50-ml conical tube. All 16 women asked to perform this procedure found it feasible and acceptable. Among 27 samples, an average of 0.5 g of secretions (range, 0.1-1.5 g) was collected. This is a rapid and convenient self-sampling method for obtaining relatively large volumes of undiluted cervicovaginal secretions. It should prove suitable for a wide range of assays, including those involving sexually transmitted diseases, microbicides, vaginal physiology, immunology, and pathophysiology.

Method for evaluation of radiative properties of glass samples

Energy Technology Data Exchange (ETDEWEB)

Mohelnikova, Jitka [Faculty of Civil Engineering, Brno University of Technology, Veveri 95, 602 00 Brno (Czech Republic)], E-mail: mohelnikova.j@fce.vutbr.cz

2008-04-15

The paper presents a simple calculation method which serves for an evaluation of radiative properties of window glasses. The method is based on a computer simulation model of the energy balance of a thermally insulated box with selected glass samples. A temperature profile of the air inside of the box with a glass sample exposed to affecting radiation was determined for defined boundary conditions. The spectral range of the radiation was considered in the interval between 280 and 2500 nm. This interval is adequate to the spectral range of solar radiation affecting windows in building facades. The air temperature rise within the box was determined in a response to the affecting radiation in the time between the beginning of the radiation exposition and the time of steady-state thermal conditions. The steady state temperature inside of the insulated box serves for the evaluation of the box energy balance and determination of the glass sample radiative properties. These properties are represented by glass characteristics as mean values of transmittance, reflectance and absorptance calculated for a defined spectral range. The data of the computer simulations were compared to experimental measurements on a real model of the insulated box. Results of both the calculations and measurements are in a good compliance. The method is recommended for preliminary evaluation of window glass radiative properties which serve as data for energy evaluation of buildings.

PhyloChip™ microarray comparison of sampling methods used for coral microbial ecology

Science.gov (United States)

Kellogg, Christina A.; Piceno, Yvette M.; Tom, Lauren M.; DeSantis, Todd Z.; Zawada, David G.; Andersen, Gary L.

2012-01-01

Interest in coral microbial ecology has been increasing steadily over the last decade, yet standardized methods of sample collection still have not been defined. Two methods were compared for their ability to sample coral-associated microbial communities: tissue punches and foam swabs, the latter being less invasive and preferred by reef managers. Four colonies of star coral, Montastraea annularis, were sampled in the Dry Tortugas National Park (two healthy and two with white plague disease). The PhyloChip™ G3 microarray was used to assess microbial community structure of amplified 16S rRNA gene sequences. Samples clustered based on methodology rather than coral colony. Punch samples from healthy and diseased corals were distinct. All swab samples clustered closely together with the seawater control and did not group according to the health state of the corals. Although more microbial taxa were detected by the swab method, there is a much larger overlap between the water control and swab samples than punch samples, suggesting some of the additional diversity is due to contamination from water absorbed by the swab. While swabs are useful for noninvasive studies of the coral surface mucus layer, these results show that they are not optimal for studies of coral disease.

A Proteomics Sample Preparation Method for Mature, Recalcitrant Leaves of Perennial Plants

Science.gov (United States)

Na, Zhang; Chengying, Lao; Bo, Wang; Dingxiang, Peng; Lijun, Liu

2014-01-01

Sample preparation is key to the success of proteomics studies. In the present study, two sample preparation methods were tested for their suitability on the mature, recalcitrant leaves of six representative perennial plants (grape, plum, pear, peach, orange, and ramie). An improved sample preparation method was obtained: Tris and Triton X-100 were added together instead of CHAPS to the lysis buffer, and a 20% TCA-water solution and 100% precooled acetone were added after the protein extraction for the further purification of protein. This method effectively eliminates nonprotein impurities and obtains a clear two-dimensional gel electrophoresis array. The method facilitates the separation of high-molecular-weight proteins and increases the resolution of low-abundance proteins. This method provides a widely applicable and economically feasible technology for the proteomic study of the mature, recalcitrant leaves of perennial plants. PMID:25028960

A proteomics sample preparation method for mature, recalcitrant leaves of perennial plants.

Directory of Open Access Journals (Sweden)

Deng Gang

Full Text Available Sample preparation is key to the success of proteomics studies. In the present study, two sample preparation methods were tested for their suitability on the mature, recalcitrant leaves of six representative perennial plants (grape, plum, pear, peach, orange, and ramie. An improved sample preparation method was obtained: Tris and Triton X-100 were added together instead of CHAPS to the lysis buffer, and a 20% TCA-water solution and 100% precooled acetone were added after the protein extraction for the further purification of protein. This method effectively eliminates nonprotein impurities and obtains a clear two-dimensional gel electrophoresis array. The method facilitates the separation of high-molecular-weight proteins and increases the resolution of low-abundance proteins. This method provides a widely applicable and economically feasible technology for the proteomic study of the mature, recalcitrant leaves of perennial plants.

A Sequential Kriging reliability analysis method with characteristics of adaptive sampling regions and parallelizability

International Nuclear Information System (INIS)

Wen, Zhixun; Pei, Haiqing; Liu, Hai; Yue, Zhufeng

2016-01-01

The sequential Kriging reliability analysis (SKRA) method has been developed in recent years for nonlinear implicit response functions which are expensive to evaluate. This type of method includes EGRA: the efficient reliability analysis method, and AK-MCS: the active learning reliability method combining Kriging model and Monte Carlo simulation. The purpose of this paper is to improve SKRA by adaptive sampling regions and parallelizability. The adaptive sampling regions strategy is proposed to avoid selecting samples in regions where the probability density is so low that the accuracy of these regions has negligible effects on the results. The size of the sampling regions is adapted according to the failure probability calculated by last iteration. Two parallel strategies are introduced and compared, aimed at selecting multiple sample points at a time. The improvement is verified through several troublesome examples. - Highlights: • The ISKRA method improves the efficiency of SKRA. • Adaptive sampling regions strategy reduces the number of needed samples. • The two parallel strategies reduce the number of needed iterations. • The accuracy of the optimal value impacts the number of samples significantly.

Sample processing method for the determination of perchlorate in milk

International Nuclear Information System (INIS)

Dyke, Jason V.; Kirk, Andrea B.; Kalyani Martinelango, P.; Dasgupta, Purnendu K.

2006-01-01

In recent years, many different water sources and foods have been reported to contain perchlorate. Studies indicate that significant levels of perchlorate are present in both human and dairy milk. The determination of perchlorate in milk is particularly important due to its potential health impact on infants and children. As for many other biological samples, sample preparation is more time consuming than the analysis itself. The concurrent presence of large amounts of fats, proteins, carbohydrates, etc., demands some initial cleanup; otherwise the separation column lifetime and the limit of detection are both greatly compromised. Reported milk processing methods require the addition of chemicals such as ethanol, acetic acid or acetonitrile. Reagent addition is undesirable in trace analysis. We report here an essentially reagent-free sample preparation method for the determination of perchlorate in milk. Milk samples are spiked with isotopically labeled perchlorate and centrifuged to remove lipids. The resulting liquid is placed in a disposable centrifugal ultrafilter device with a molecular weight cutoff of 10 kDa, and centrifuged. Approximately 5-10 ml of clear liquid, ready for analysis, is obtained from a 20 ml milk sample. Both bovine and human milk samples have been successfully processed and analyzed by ion chromatography-mass spectrometry (IC-MS). Standard addition experiments show good recoveries. The repeatability of the analytical result for the same sample in multiple sample cleanup runs ranged from 3 to 6% R.S.D. This processing technique has also been successfully applied for the determination of iodide and thiocyanate in milk

A Method for Microalgae Proteomics Analysis Based on Modified Filter-Aided Sample Preparation.

Science.gov (United States)

Li, Song; Cao, Xupeng; Wang, Yan; Zhu, Zhen; Zhang, Haowei; Xue, Song; Tian, Jing

2017-11-01

With the fast development of microalgal biofuel researches, the proteomics studies of microalgae increased quickly. A filter-aided sample preparation (FASP) method is widely used proteomics sample preparation method since 2009. Here, a method of microalgae proteomics analysis based on modified filter-aided sample preparation (mFASP) was described to meet the characteristics of microalgae cells and eliminate the error caused by over-alkylation. Using Chlamydomonas reinhardtii as the model, the prepared sample was tested by standard LC-MS/MS and compared with the previous reports. The results showed mFASP is suitable for most of occasions of microalgae proteomics studies.

Fast egg collection method greatly improves randomness of egg sampling in Drosophila melanogaster

DEFF Research Database (Denmark)

Schou, Mads Fristrup

2013-01-01

When obtaining samples for population genetic studies, it is essential that the sampling is random. For Drosophila, one of the crucial steps in sampling experimental flies is the collection of eggs. Here an egg collection method is presented, which randomizes the eggs in a water column...... and diminishes environmental variance. This method was compared with a traditional egg collection method where eggs are collected directly from the medium. Within each method the observed and expected standard deviations of egg-to-adult viability were compared, whereby the difference in the randomness...... and to obtain a representative collection of genotypes, the method presented here is strongly recommended when collecting eggs from Drosophila....

Adaptive cluster sampling: An efficient method for assessing inconspicuous species

Science.gov (United States)

Andrea M. Silletti; Joan Walker

2003-01-01

Restorationistis typically evaluate the success of a project by estimating the population sizes of species that have been planted or seeded. Because total census is raely feasible, they must rely on sampling methods for population estimates. However, traditional random sampling designs may be inefficient for species that, for one reason or another, are challenging to...

A distance limited method for sampling downed coarse woody debris

Science.gov (United States)

Jeffrey H. Gove; Mark J. Ducey; Harry T. Valentine; Michael S. Williams

2012-01-01

A new sampling method for down coarse woody debris is proposed based on limiting the perpendicular distance from individual pieces to a randomly chosen sample point. Two approaches are presented that allow different protocols to be used to determine field measurements; estimators for each protocol are also developed. Both protocols are compared via simulation against...

A novel heterogeneous training sample selection method on space-time adaptive processing

Science.gov (United States)

Wang, Qiang; Zhang, Yongshun; Guo, Yiduo

2018-04-01

The performance of ground target detection about space-time adaptive processing (STAP) decreases when non-homogeneity of clutter power is caused because of training samples contaminated by target-like signals. In order to solve this problem, a novel nonhomogeneous training sample selection method based on sample similarity is proposed, which converts the training sample selection into a convex optimization problem. Firstly, the existing deficiencies on the sample selection using generalized inner product (GIP) are analyzed. Secondly, the similarities of different training samples are obtained by calculating mean-hausdorff distance so as to reject the contaminated training samples. Thirdly, cell under test (CUT) and the residual training samples are projected into the orthogonal subspace of the target in the CUT, and mean-hausdorff distances between the projected CUT and training samples are calculated. Fourthly, the distances are sorted in order of value and the training samples which have the bigger value are selective preference to realize the reduced-dimension. Finally, simulation results with Mountain-Top data verify the effectiveness of the proposed method.

Comparing two sampling methods to engage hard-to-reach communities in research priority setting.

Science.gov (United States)

Valerio, Melissa A; Rodriguez, Natalia; Winkler, Paula; Lopez, Jaime; Dennison, Meagen; Liang, Yuanyuan; Turner, Barbara J

2016-10-28

Effective community-partnered and patient-centered outcomes research needs to address community priorities. However, optimal sampling methods to engage stakeholders from hard-to-reach, vulnerable communities to generate research priorities have not been identified. In two similar rural, largely Hispanic communities, a community advisory board guided recruitment of stakeholders affected by chronic pain using a different method in each community: 1) snowball sampling, a chain- referral method or 2) purposive sampling to recruit diverse stakeholders. In both communities, three groups of stakeholders attended a series of three facilitated meetings to orient, brainstorm, and prioritize ideas (9 meetings/community). Using mixed methods analysis, we compared stakeholder recruitment and retention as well as priorities from both communities' stakeholders on mean ratings of their ideas based on importance and feasibility for implementation in their community. Of 65 eligible stakeholders in one community recruited by snowball sampling, 55 (85 %) consented, 52 (95 %) attended the first meeting, and 36 (65 %) attended all 3 meetings. In the second community, the purposive sampling method was supplemented by convenience sampling to increase recruitment. Of 69 stakeholders recruited by this combined strategy, 62 (90 %) consented, 36 (58 %) attended the first meeting, and 26 (42 %) attended all 3 meetings. Snowball sampling recruited more Hispanics and disabled persons (all P research, focusing on non-pharmacologic interventions for management of chronic pain. Ratings on importance and feasibility for community implementation differed only on the importance of massage services (P = 0.045) which was higher for the purposive/convenience sampling group and for city improvements/transportation services (P = 0.004) which was higher for the snowball sampling group. In each of the two similar hard-to-reach communities, a community advisory board partnered with researchers

Ionizing radiation as optimization method for aluminum detection from drinking water samples

International Nuclear Information System (INIS)

Bazante-Yamguish, Renata; Geraldo, Aurea Beatriz C.; Moura, Eduardo; Manzoli, Jose Eduardo

2013-01-01

The presence of organic compounds in water samples is often responsible for metal complexation; depending on the analytic method, the organic fraction may dissemble the evaluation of the real values of metal concentration. Pre-treatment of the samples is advised when organic compounds are interfering agents, and thus sample mineralization may be accomplished by several chemical and/or physical methods. Here, the ionizing radiation was used as an advanced oxidation process (AOP), for sample pre-treatment before the analytic determination of total and dissolved aluminum by ICP-OES in drinking water samples from wells and spring source located at Billings dam region. Before irradiation, the spring source and wells' samples showed aluminum levels of 0.020 mg/l and 0.2 mg/l respectively; after irradiation, both samples showed a 8-fold increase of aluminum concentration. These results are discussed considering other physical and chemical parameters and peculiarities of sample sources. (author)

Solvent extraction method for rapid separation of strontium-90 in milk and food samples

International Nuclear Information System (INIS)

Hingorani, S.B.; Sathe, A.P.

1991-01-01

A solvent extraction method, using tributyl phosphate, for rapid separation of strontium-90 in milk and other food samples has been presented in this report in view of large number of samples recieved after Chernobyl accident for checking radioactive contamination. The earlier nitration method in use for the determination of 90 Sr through its daughter 90 Y takes over two weeks for analysis of a sample. While by this extraction method it takes only 4 to 5 hours for sample analysis. Complete estimation including initial counting can be done in a single day. The chemical recovery varies between 80-90% compared to nitration method which is 65-80%. The purity of the method has been established by following the decay of yttrium-90 separated. Some of the results obtained by adopting this chemical method for food analysis are included. The method is, thus, found to be rapid and convenient for accurate estimation of strontium-90 in milk and food samples. (author). 2 tabs., 1 fig

Mapping species distributions with MAXENT using a geographically biased sample of presence data: a performance assessment of methods for correcting sampling bias.

Science.gov (United States)

Fourcade, Yoan; Engler, Jan O; Rödder, Dennis; Secondi, Jean

2014-01-01

MAXENT is now a common species distribution modeling (SDM) tool used by conservation practitioners for predicting the distribution of a species from a set of records and environmental predictors. However, datasets of species occurrence used to train the model are often biased in the geographical space because of unequal sampling effort across the study area. This bias may be a source of strong inaccuracy in the resulting model and could lead to incorrect predictions. Although a number of sampling bias correction methods have been proposed, there is no consensual guideline to account for it. We compared here the performance of five methods of bias correction on three datasets of species occurrence: one "virtual" derived from a land cover map, and two actual datasets for a turtle (Chrysemys picta) and a salamander (Plethodon cylindraceus). We subjected these datasets to four types of sampling biases corresponding to potential types of empirical biases. We applied five correction methods to the biased samples and compared the outputs of distribution models to unbiased datasets to assess the overall correction performance of each method. The results revealed that the ability of methods to correct the initial sampling bias varied greatly depending on bias type, bias intensity and species. However, the simple systematic sampling of records consistently ranked among the best performing across the range of conditions tested, whereas other methods performed more poorly in most cases. The strong effect of initial conditions on correction performance highlights the need for further research to develop a step-by-step guideline to account for sampling bias. However, this method seems to be the most efficient in correcting sampling bias and should be advised in most cases.

Sampling for Patient Exit Interviews: Assessment of Methods Using Mathematical Derivation and Computer Simulations.

Science.gov (United States)

Geldsetzer, Pascal; Fink, Günther; Vaikath, Maria; Bärnighausen, Till

2018-02-01

(1) To evaluate the operational efficiency of various sampling methods for patient exit interviews; (2) to discuss under what circumstances each method yields an unbiased sample; and (3) to propose a new, operationally efficient, and unbiased sampling method. Literature review, mathematical derivation, and Monte Carlo simulations. Our simulations show that in patient exit interviews it is most operationally efficient if the interviewer, after completing an interview, selects the next patient exiting the clinical consultation. We demonstrate mathematically that this method yields a biased sample: patients who spend a longer time with the clinician are overrepresented. This bias can be removed by selecting the next patient who enters, rather than exits, the consultation room. We show that this sampling method is operationally more efficient than alternative methods (systematic and simple random sampling) in most primary health care settings. Under the assumption that the order in which patients enter the consultation room is unrelated to the length of time spent with the clinician and the interviewer, selecting the next patient entering the consultation room tends to be the operationally most efficient unbiased sampling method for patient exit interviews. © 2016 The Authors. Health Services Research published by Wiley Periodicals, Inc. on behalf of Health Research and Educational Trust.

Sampling Methods for Detection and Monitoring of the Asian Citrus Psyllid (Hemiptera: Psyllidae).

Science.gov (United States)

Monzo, C; Arevalo, H A; Jones, M M; Vanaclocha, P; Croxton, S D; Qureshi, J A; Stansly, P A

2015-06-01

The Asian citrus psyllid (ACP), Diaphorina citri Kuwayama is a key pest of citrus due to its role as vector of citrus greening disease or "huanglongbing." ACP monitoring is considered an indispensable tool for management of vector and disease. In the present study, datasets collected between 2009 and 2013 from 245 citrus blocks were used to evaluate precision, sensitivity for detection, and efficiency of five sampling methods. The number of samples needed to reach a 0.25 standard error-mean ratio was estimated using Taylor's power law and used to compare precision among sampling methods. Comparison of detection sensitivity and time expenditure (cost) between stem-tap and other sampling methodologies conducted consecutively at the same location were also assessed. Stem-tap sampling was the most efficient sampling method when ACP densities were moderate to high and served as the basis for comparison with all other methods. Protocols that grouped trees near randomly selected locations across the block were more efficient than sampling trees at random across the block. Sweep net sampling was similar to stem-taps in number of captures per sampled unit, but less precise at any ACP density. Yellow sticky traps were 14 times more sensitive than stem-taps but much more time consuming and thus less efficient except at very low population densities. Visual sampling was efficient for detecting and monitoring ACP at low densities. Suction sampling was time consuming and taxing but the most sensitive of all methods for detection of sparse populations. This information can be used to optimize ACP monitoring efforts. © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Computational methods and modeling. 1. Sampling a Position Uniformly in a Trilinear Hexahedral Volume

International Nuclear Information System (INIS)

Urbatsch, Todd J.; Evans, Thomas M.; Hughes, H. Grady

2001-01-01

Monte Carlo particle transport plays an important role in some multi-physics simulations. These simulations, which may additionally involve deterministic calculations, typically use a hexahedral or tetrahedral mesh. Trilinear hexahedrons are attractive for physics calculations because faces between cells are uniquely defined, distance-to-boundary calculations are deterministic, and hexahedral meshes tend to require fewer cells than tetrahedral meshes. We discuss one aspect of Monte Carlo transport: sampling a position in a tri-linear hexahedron, which is made up of eight control points, or nodes, and six bilinear faces, where each face is defined by four non-coplanar nodes in three-dimensional Cartesian space. We derive, code, and verify the exact sampling method and propose an approximation to it. Our proposed approximate method uses about one-third the memory and can be twice as fast as the exact sampling method, but we find that its inaccuracy limits its use to well-behaved hexahedrons. Daunted by the expense of the exact method, we propose an alternate approximate sampling method. First, calculate beforehand an approximate volume for each corner of the hexahedron by taking one-eighth of the volume of an imaginary parallelepiped defined by the corner node and the three nodes to which it is directly connected. For the sampling, assume separability in the parameters, and sample each parameter, in turn, from a linear pdf defined by the sum of the four corner volumes at each limit (-1 and 1) of the parameter. This method ignores the quadratic portion of the pdf, but it requires less storage, has simpler sampling, and needs no extra, on-the-fly calculations. We simplify verification by designing tests that consist of one or more cells that entirely fill a unit cube. Uniformly sampling complicated cells that fill a unit cube will result in uniformly sampling the unit cube. Unit cubes are easily analyzed. The first problem has four wedges (or tents, or A frames) whose

A direct sampling method for inverse electromagnetic medium scattering

KAUST Repository

Ito, Kazufumi; Jin, Bangti; Zou, Jun

2013-01-01

In this paper, we study the inverse electromagnetic medium scattering problem of estimating the support and shape of medium scatterers from scattered electric/magnetic near-field data. We shall develop a novel direct sampling method based

Geostatistical Sampling Methods for Efficient Uncertainty Analysis in Flow and Transport Problems

Science.gov (United States)

Liodakis, Stylianos; Kyriakidis, Phaedon; Gaganis, Petros

2015-04-01

In hydrogeological applications involving flow and transport of in heterogeneous porous media the spatial distribution of hydraulic conductivity is often parameterized in terms of a lognormal random field based on a histogram and variogram model inferred from data and/or synthesized from relevant knowledge. Realizations of simulated conductivity fields are then generated using geostatistical simulation involving simple random (SR) sampling and are subsequently used as inputs to physically-based simulators of flow and transport in a Monte Carlo framework for evaluating the uncertainty in the spatial distribution of solute concentration due to the uncertainty in the spatial distribution of hydraulic con- ductivity [1]. Realistic uncertainty analysis, however, calls for a large number of simulated concentration fields; hence, can become expensive in terms of both time and computer re- sources. A more efficient alternative to SR sampling is Latin hypercube (LH) sampling, a special case of stratified random sampling, which yields a more representative distribution of simulated attribute values with fewer realizations [2]. Here, term representative implies realizations spanning efficiently the range of possible conductivity values corresponding to the lognormal random field. In this work we investigate the efficiency of alternative methods to classical LH sampling within the context of simulation of flow and transport in a heterogeneous porous medium. More precisely, we consider the stratified likelihood (SL) sampling method of [3], in which attribute realizations are generated using the polar simulation method by exploring the geometrical properties of the multivariate Gaussian distribution function. In addition, we propose a more efficient version of the above method, here termed minimum energy (ME) sampling, whereby a set of N representative conductivity realizations at M locations is constructed by: (i) generating a representative set of N points distributed on the

Comparing two sampling methods to engage hard-to-reach communities in research priority setting

Directory of Open Access Journals (Sweden)

Melissa A. Valerio

2016-10-01

Full Text Available Abstract Background Effective community-partnered and patient-centered outcomes research needs to address community priorities. However, optimal sampling methods to engage stakeholders from hard-to-reach, vulnerable communities to generate research priorities have not been identified. Methods In two similar rural, largely Hispanic communities, a community advisory board guided recruitment of stakeholders affected by chronic pain using a different method in each community: 1 snowball sampling, a chain- referral method or 2 purposive sampling to recruit diverse stakeholders. In both communities, three groups of stakeholders attended a series of three facilitated meetings to orient, brainstorm, and prioritize ideas (9 meetings/community. Using mixed methods analysis, we compared stakeholder recruitment and retention as well as priorities from both communities’ stakeholders on mean ratings of their ideas based on importance and feasibility for implementation in their community. Results Of 65 eligible stakeholders in one community recruited by snowball sampling, 55 (85 % consented, 52 (95 % attended the first meeting, and 36 (65 % attended all 3 meetings. In the second community, the purposive sampling method was supplemented by convenience sampling to increase recruitment. Of 69 stakeholders recruited by this combined strategy, 62 (90 % consented, 36 (58 % attended the first meeting, and 26 (42 % attended all 3 meetings. Snowball sampling recruited more Hispanics and disabled persons (all P < 0.05. Despite differing recruitment strategies, stakeholders from the two communities identified largely similar ideas for research, focusing on non-pharmacologic interventions for management of chronic pain. Ratings on importance and feasibility for community implementation differed only on the importance of massage services (P = 0.045 which was higher for the purposive/convenience sampling group and for city improvements

Two methods of self-sampling compared to clinician sampling to detect reproductive tract infections in Gugulethu, South Africa

NARCIS (Netherlands)

van de Wijgert, Janneke; Altini, Lydia; Jones, Heidi; de Kock, Alana; Young, Taryn; Williamson, Anna-Lise; Hoosen, Anwar; Coetzee, Nicol

2006-01-01

To assess the validity, feasibility, and acceptability of 2 methods of self-sampling compared to clinician sampling during a speculum examination. To improve screening for reproductive tract infections (RTIs) in resource-poor settings. In a public clinic in Cape Town, 450 women underwent a speculum

Nonhazardous solvent composition and method for cleaning metal surfaces

International Nuclear Information System (INIS)

Googin, J.M.; Simandl, R.F.; Thompson, L.M.

1993-01-01

A solvent composition for displacing greasy and oily contaminants as well as water and/or aqueous residue from metallic surfaces, especially surfaces of radioactive materials so that such surfaces can be wiped clean of the displaced contaminants, water and/or aqueous residue. The solvent composition consists essentially of a blend of nonpolar aliphatic hydrocarbon solvent having a minimum flash point of about 140 F and 2 to 25 volume percent of a polar solvent having a flash point sufficiently high so as to provide the solvent composition with a minimum flash point of at least 140 F. The solvent composition is nonhazardous so that when it is used to clean the surfaces of radioactive materials the waste in the form of paper or cloth wipes, lab coats and the like used in the cleaning operation is not considered to be mixed waste composed of a hazardous solvent and a radioactive material

The use of physical methods for elemental analysis of ecological samples

International Nuclear Information System (INIS)

Kudryashov, V.I.; Zhuravleva, E.L.; Maslov, O.D.

1996-01-01

The possibility of the application of difference X-ray and instrumental activation methods elemental analysis of rock ice, snow, water, soil and other natural samples was investigated. The content of some elements in ice samples from the glaciers of the Pamirs-Alaj mountain system for period 1973-1984 years has been determined. The recommendations for the choice of analysis methods with the aim of the environmental control have been given. (author). 10 refs., 6 figs., 1 tab

Application of WSP method in analysis of environmental samples

International Nuclear Information System (INIS)

Stacho, M.; Slugen, V.; Hinca, R.; Sojak, S.; Krnac, S.

2014-01-01

Detection of activity in natural samples is specific especially because of its low level and high background interferences. Reduction of background interferences could be reached using low background chamber. Measurement geometry in shape of Marinelli beaker is commonly used according to low level of activity in natural samples. The Peak Net Area (PNA) method is the world-wide accepted technique for analysis of gamma-ray spectra. It is based on the net area calculation of the full energy peak, therefore, it takes into account only a fraction of measured gamma-ray spectrum. On the other hand, the Whole Spectrum Processing (WSP) approach to the gamma analysis makes possible to use entire information being in the spectrum. This significantly raises efficiency and improves energy resolution of the analysis. A principal step for the WSP application is building up the suitable response operator. Problems are put in an appearance when suitable standard calibration sources are unavailable. It may be occurred in the case of large volume samples and/or in the analysis of high energy range. Combined experimental and mathematical calibration may be a suitable solution. Many different detectors have been used to register the gamma ray and its energy. HPGe detectors produce the highest resolution commonly available today. Therefore they are they the most often used detectors in natural samples activity analysis. Scintillation detectors analysed using PNA method could be also used in simple cases, but for complicated spectra are practically inapplicable. WSP approach improves resolution of scintillation detectors and expands their applicability. WSP method allowed significant improvement of the energetic resolution and separation of "1"3"7Cs 661 keV peak from "2"1"4Bi 609 keV peak. At the other hand the statistical fluctuations in the lower part of the spectrum highlighted by background subtraction causes that this part is still not reliably analyzable. (authors)

A fast learning method for large scale and multi-class samples of SVM

Science.gov (United States)

Fan, Yu; Guo, Huiming

2017-06-01

A multi-class classification SVM(Support Vector Machine) fast learning method based on binary tree is presented to solve its low learning efficiency when SVM processing large scale multi-class samples. This paper adopts bottom-up method to set up binary tree hierarchy structure, according to achieved hierarchy structure, sub-classifier learns from corresponding samples of each node. During the learning, several class clusters are generated after the first clustering of the training samples. Firstly, central points are extracted from those class clusters which just have one type of samples. For those which have two types of samples, cluster numbers of their positive and negative samples are set respectively according to their mixture degree, secondary clustering undertaken afterwards, after which, central points are extracted from achieved sub-class clusters. By learning from the reduced samples formed by the integration of extracted central points above, sub-classifiers are obtained. Simulation experiment shows that, this fast learning method, which is based on multi-level clustering, can guarantee higher classification accuracy, greatly reduce sample numbers and effectively improve learning efficiency.

Statistical methods for detecting differentially abundant features in clinical metagenomic samples.

Directory of Open Access Journals (Sweden)

James Robert White

2009-04-01

Full Text Available Numerous studies are currently underway to characterize the microbial communities inhabiting our world. These studies aim to dramatically expand our understanding of the microbial biosphere and, more importantly, hope to reveal the secrets of the complex symbiotic relationship between us and our commensal bacterial microflora. An important prerequisite for such discoveries are computational tools that are able to rapidly and accurately compare large datasets generated from complex bacterial communities to identify features that distinguish them.We present a statistical method for comparing clinical metagenomic samples from two treatment populations on the basis of count data (e.g. as obtained through sequencing to detect differentially abundant features. Our method, Metastats, employs the false discovery rate to improve specificity in high-complexity environments, and separately handles sparsely-sampled features using Fisher's exact test. Under a variety of simulations, we show that Metastats performs well compared to previously used methods, and significantly outperforms other methods for features with sparse counts. We demonstrate the utility of our method on several datasets including a 16S rRNA survey of obese and lean human gut microbiomes, COG functional profiles of infant and mature gut microbiomes, and bacterial and viral metabolic subsystem data inferred from random sequencing of 85 metagenomes. The application of our method to the obesity dataset reveals differences between obese and lean subjects not reported in the original study. For the COG and subsystem datasets, we provide the first statistically rigorous assessment of the differences between these populations. The methods described in this paper are the first to address clinical metagenomic datasets comprising samples from multiple subjects. Our methods are robust across datasets of varied complexity and sampling level. While designed for metagenomic applications, our software

Effect of the absolute statistic on gene-sampling gene-set analysis methods.

Science.gov (United States)

Nam, Dougu

2017-06-01

Gene-set enrichment analysis and its modified versions have commonly been used for identifying altered functions or pathways in disease from microarray data. In particular, the simple gene-sampling gene-set analysis methods have been heavily used for datasets with only a few sample replicates. The biggest problem with this approach is the highly inflated false-positive rate. In this paper, the effect of absolute gene statistic on gene-sampling gene-set analysis methods is systematically investigated. Thus far, the absolute gene statistic has merely been regarded as a supplementary method for capturing the bidirectional changes in each gene set. Here, it is shown that incorporating the absolute gene statistic in gene-sampling gene-set analysis substantially reduces the false-positive rate and improves the overall discriminatory ability. Its effect was investigated by power, false-positive rate, and receiver operating curve for a number of simulated and real datasets. The performances of gene-set analysis methods in one-tailed (genome-wide association study) and two-tailed (gene expression data) tests were also compared and discussed.

Microbial diversity in fecal samples depends on DNA extraction method

DEFF Research Database (Denmark)

Mirsepasi, Hengameh; Persson, Søren; Struve, Carsten

2014-01-01

was to evaluate two different DNA extraction methods in order to choose the most efficient method for studying intestinal bacterial diversity using Denaturing Gradient Gel Electrophoresis (DGGE). FINDINGS: In this study, a semi-automatic DNA extraction system (easyMag®, BioMérieux, Marcy I'Etoile, France......BACKGROUND: There are challenges, when extracting bacterial DNA from specimens for molecular diagnostics, since fecal samples also contain DNA from human cells and many different substances derived from food, cell residues and medication that can inhibit downstream PCR. The purpose of the study...... by easyMag® from the same fecal samples. Furthermore, DNA extracts obtained using easyMag® seemed to contain inhibitory compounds, since in order to perform a successful PCR-analysis, the sample should be diluted at least 10 times. DGGE performed on PCR from DNA extracted by QIAamp DNA Stool Mini Kit DNA...

Detection and monitoring of invasive exotic plants: a comparison of four sampling methods

Science.gov (United States)

Cynthia D. Huebner

2007-01-01

The ability to detect and monitor exotic invasive plants is likely to vary depending on the sampling method employed. Methods with strong qualitative thoroughness for species detection often lack the intensity necessary to monitor vegetation change. Four sampling methods (systematic plot, stratified-random plot, modified Whittaker, and timed meander) in hemlock and red...

Evaluation of Stress Loaded Steel Samples Using Selected Electromagnetic Methods

International Nuclear Information System (INIS)

Chady, T.

2004-01-01

In this paper the magnetic leakage flux and eddy current method were used to evaluate changes of materials' properties caused by stress. Seven samples made of ferromagnetic material with different level of applied stress were prepared. First, the leakage magnetic fields were measured by scanning the surface of the specimens with GMR gradiometer. Next, the same samples were evaluated using an eddy current sensor. A comparison between results obtained from both methods was carried out. Finally, selected parameters of the measured signal were calculated and utilized to evaluate level of the applied stress. A strong coincidence between amount of the applied stress and the maximum amplitude of the derivative was confirmed

Suitability of the line intersect method for sampling hardwood logging residues

Science.gov (United States)

A. Jeff Martin

1976-01-01

The line intersect method of sampling logging residues was tested in Appalachian hardwoods and was found to provide unbiased estimates of the volume of residue in cubic feet per acre. Thirty-two chains of sample line were established on each of sixteen 1-acre plots on cutover areas in a variety of conditions. Estimates from these samples were then compared to actual...

Transuranic waste characterization sampling and analysis methods manual. Revision 1

International Nuclear Information System (INIS)

Suermann, J.F.

1996-04-01

This Methods Manual provides a unified source of information on the sampling and analytical techniques that enable Department of Energy (DOE) facilities to comply with the requirements established in the current revision of the Transuranic Waste Characterization Quality Assurance Program Plan (QAPP) for the Waste Isolation Pilot Plant (WIPP) Transuranic (TRU) Waste Characterization Program (the Program) and the WIPP Waste Analysis Plan. This Methods Manual includes all of the testing, sampling, and analytical methodologies accepted by DOE for use in implementing the Program requirements specified in the QAPP and the WIPP Waste Analysis Plan. The procedures in this Methods Manual are comprehensive and detailed and are designed to provide the necessary guidance for the preparation of site-specific procedures. With some analytical methods, such as Gas Chromatography/Mass Spectrometry, the Methods Manual procedures may be used directly. With other methods, such as nondestructive characterization, the Methods Manual provides guidance rather than a step-by-step procedure. Sites must meet all of the specified quality control requirements of the applicable procedure. Each DOE site must document the details of the procedures it will use and demonstrate the efficacy of such procedures to the Manager, National TRU Program Waste Characterization, during Waste Characterization and Certification audits

Empirical method for matrix effects correction in liquid samples

International Nuclear Information System (INIS)

Vigoda de Leyt, Dora; Vazquez, Cristina

1987-01-01

A simple method for the determination of Cr, Ni and Mo in stainless steels is presented. In order to minimize the matrix effects, the conditions of liquid system to dissolve stainless steels chips has been developed. Pure element solutions were used as standards. Preparation of synthetic solutions with all the elements of steel and also mathematic corrections are avoided. It results in a simple chemical operation which simplifies the method of analysis. The variance analysis of the results obtained with steel samples show that the three elements may be determined from the comparison with the analytical curves obtained with the pure elements if the same parameters in the calibration curves are used. The accuracy and the precision were checked against other techniques using the British Chemical Standards of the Bureau of Anlysed Samples Ltd. (England). (M.E.L.) [es

Small Body GN and C Research Report: G-SAMPLE - An In-Flight Dynamical Method for Identifying Sample Mass [External Release Version

Science.gov (United States)

Carson, John M., III; Bayard, David S.

2006-01-01

G-SAMPLE is an in-flight dynamical method for use by sample collection missions to identify the presence and quantity of collected sample material. The G-SAMPLE method implements a maximum-likelihood estimator to identify the collected sample mass, based on onboard force sensor measurements, thruster firings, and a dynamics model of the spacecraft. With G-SAMPLE, sample mass identification becomes a computation rather than an extra hardware requirement; the added cost of cameras or other sensors for sample mass detection is avoided. Realistic simulation examples are provided for a spacecraft configuration with a sample collection device mounted on the end of an extended boom. In one representative example, a 1000 gram sample mass is estimated to within 110 grams (95% confidence) under realistic assumptions of thruster profile error, spacecraft parameter uncertainty, and sensor noise. For convenience to future mission design, an overall sample-mass estimation error budget is developed to approximate the effect of model uncertainty, sensor noise, data rate, and thrust profile error on the expected estimate of collected sample mass.

Effect of sample preparation methods on photometric determination of the tellurium and cobalt content in the samples of copper concentrates

Directory of Open Access Journals (Sweden)

Viktoriya Butenko

2016-03-01

Full Text Available Methods of determination of cobalt and nickel in copper concentrates currently used in factory laboratories are very labor intensive and time consuming. The limiting stage of the analysis is preliminary chemical sample preparation. Carrying out the decomposition process of industrial samples with concentrated mineral acids in open systems does not allow to improve the metrological characteristics of the methods, for this reason improvement the methods of sample preparation is quite relevant and has a practical interest. The work was dedicated to the determination of the optimal conditions of preliminary chemical preparation of copper concentrate samples for the subsequent determination of cobalt and tellurium in the obtained solution using tellurium-spectrophotometric method. Decomposition of the samples was carried out by acid dissolving in individual mineral acids and their mixtures by heating in an open system as well as by using ultrasonification and microwave radiation in a closed system. In order to select the optimal conditions for the decomposition of the samples in a closed system the phase contact time and ultrasonic generator’s power were varied. Intensification of the processes of decomposition of copper concentrates with nitric acid (1:1, ultrasound and microwave radiation allowed to transfer quantitatively cobalt and tellurium into solution spending 20 and 30 min respectively. This reduced the amount of reactants used and improved the accuracy of determination by running the process in strictly identical conditions.

Estimating sample size for a small-quadrat method of botanical ...

African Journals Online (AJOL)

Reports the results of a study conducted to determine an appropriate sample size for a small-quadrat method of botanical survey for application in the Mixed Bushveld of South Africa. Species density and grass density were measured using a small-quadrat method in eight plant communities in the Nylsvley Nature Reserve.

Method for analysing radium in powder samples and its application to uranium prospecting

International Nuclear Information System (INIS)

Gong Xinxi; Hu Minzhi.

1987-01-01

The decayed daughter of Rn released from the power sample (soil) in a sealed bottle were collected on a piece of copper and the radium in the sample can be measured by counting α-particles with an Alphameter for uranium prospection, thus it is called the radium method. This method has many advantages, such as high sensitivity (the lowest limit of detection for radium sample per gram is 2.7 x 10 -15 g), high efficiency, low cost and easy to use. On the basis of measuring more than 700 samples taken along 20 sections in 8 deposits, the results show that the radium method is better than γ-measurement and equal to 210 Po method for the capability to descover anomalies. The author also summarizes the anomaly intensities of radium method, 210 Po method and γ-measurement respectively at the surface with deep blind ores, with or without surficial mineralization, and the figures of their profiles and the variation of Ra/ 210 Po ratios. According to the above-mentioned distinguishing features, the uranium mineralization located in deep and/or shallow parts can be distinguishd. The combined application of radium, 210 Po and γ-measurement methods may be regarded as one of the important methods used for anomaly assessment. Based on the experiments of the radium measurements with 771 stream sediments samples in an area of 100 km 2 , it is demonstrated that the radium mehtod can be used in the stages of uranium reconnaissance and prospecting

Comparison of vapor sampling system (VSS) and in situ vapor sampling (ISVS) methods on Tanks C-107, BY-108, and S-102

International Nuclear Information System (INIS)

Huckaby, J.L.; Edwards, J.A.; Evans, J.C.

1996-05-01

The objective of this report is to evaluate the equivalency of two methods used to sample nonradioactive gases and vapors in the Hanford Site high-level waste tank headspaces. In addition to the comparison of the two sampling methods, the effects of an in-line fine particle filter on sampling results are also examined to determine whether results are adversely affected by its presence. This report discusses data from a January 1996 sampling

Optimization of fecal cytology in the dog: comparison of three sampling methods.

Science.gov (United States)

Frezoulis, Petros S; Angelidou, Elisavet; Diakou, Anastasia; Rallis, Timoleon S; Mylonakis, Mathios E

2017-09-01

Dry-mount fecal cytology (FC) is a component of the diagnostic evaluation of gastrointestinal diseases. There is limited information on the possible effect of the sampling method on the cytologic findings of healthy dogs or dogs admitted with diarrhea. We aimed to: (1) establish sampling method-specific expected values of selected cytologic parameters (isolated or clustered epithelial cells, neutrophils, lymphocytes, macrophages, spore-forming rods) in clinically healthy dogs; (2) investigate if the detection of cytologic abnormalities differs among methods in dogs admitted with diarrhea; and (3) investigate if there is any association between FC abnormalities and the anatomic origin (small- or large-bowel diarrhea) or the chronicity of diarrhea. Sampling with digital examination (DE), rectal scraping (RS), and rectal lavage (RL) was prospectively assessed in 37 healthy and 34 diarrheic dogs. The median numbers of isolated ( p = 0.000) or clustered ( p = 0.002) epithelial cells, and of lymphocytes ( p = 0.000), differed among the 3 methods in healthy dogs. In the diarrheic dogs, the RL method was the least sensitive in detecting neutrophils, and isolated or clustered epithelial cells. Cytologic abnormalities were not associated with the origin or the chronicity of diarrhea. Sampling methods differed in their sensitivity to detect abnormalities in FC; DE or RS may be of higher sensitivity compared to RL. Anatomic origin or chronicity of diarrhea do not seem to affect the detection of cytologic abnormalities.

An adaptive sampling method for variable-fidelity surrogate models using improved hierarchical kriging

Science.gov (United States)

Hu, Jiexiang; Zhou, Qi; Jiang, Ping; Shao, Xinyu; Xie, Tingli

2018-01-01

Variable-fidelity (VF) modelling methods have been widely used in complex engineering system design to mitigate the computational burden. Building a VF model generally includes two parts: design of experiments and metamodel construction. In this article, an adaptive sampling method based on improved hierarchical kriging (ASM-IHK) is proposed to refine the improved VF model. First, an improved hierarchical kriging model is developed as the metamodel, in which the low-fidelity model is varied through a polynomial response surface function to capture the characteristics of a high-fidelity model. Secondly, to reduce local approximation errors, an active learning strategy based on a sequential sampling method is introduced to make full use of the already required information on the current sampling points and to guide the sampling process of the high-fidelity model. Finally, two numerical examples and the modelling of the aerodynamic coefficient for an aircraft are provided to demonstrate the approximation capability of the proposed approach, as well as three other metamodelling methods and two sequential sampling methods. The results show that ASM-IHK provides a more accurate metamodel at the same simulation cost, which is very important in metamodel-based engineering design problems.

A novel sampling method for multiple multiscale targets from scattering amplitudes at a fixed frequency

Science.gov (United States)

Liu, Xiaodong

2017-08-01

A sampling method by using scattering amplitude is proposed for shape and location reconstruction in inverse acoustic scattering problems. Only matrix multiplication is involved in the computation, thus the novel sampling method is very easy and simple to implement. With the help of the factorization of the far field operator, we establish an inf-criterion for characterization of underlying scatterers. This result is then used to give a lower bound of the proposed indicator functional for sampling points inside the scatterers. While for the sampling points outside the scatterers, we show that the indicator functional decays like the bessel functions as the sampling point goes away from the boundary of the scatterers. We also show that the proposed indicator functional continuously depends on the scattering amplitude, this further implies that the novel sampling method is extremely stable with respect to errors in the data. Different to the classical sampling method such as the linear sampling method or the factorization method, from the numerical point of view, the novel indicator takes its maximum near the boundary of the underlying target and decays like the bessel functions as the sampling points go away from the boundary. The numerical simulations also show that the proposed sampling method can deal with multiple multiscale case, even the different components are close to each other.

Method validation and uncertainty evaluation of organically bound tritium analysis in environmental sample.

Science.gov (United States)

Huang, Yan-Jun; Zeng, Fan; Zhang, Bing; Chen, Chao-Feng; Qin, Hong-Juan; Wu, Lian-Sheng; Guo, Gui-Yin; Yang, Li-Tao; Shang-Guan, Zhi-Hong

2014-08-01

The analytical method for organically bound tritium (OBT) was developed in our laboratory. The optimized operating conditions and parameters were established for sample drying, special combustion, distillation, and measurement on a liquid scintillation spectrometer (LSC). Selected types of OBT samples such as rice, corn, rapeseed, fresh lettuce and pork were analyzed for method validation of recovery rate reproducibility, the minimum detection concentration, and the uncertainty for typical low level environmental sample was evaluated. The combustion water recovery rate of different dried environmental sample was kept at about 80%, the minimum detection concentration of OBT ranged from 0.61 to 0.89 Bq/kg (dry weight), depending on the hydrogen content. It showed that this method is suitable for OBT analysis of environmental sample with stable recovery rate, and the combustion water yield of a sample with weight about 40 g would provide sufficient quantity for measurement on LSC. Copyright © 2014 Elsevier Ltd. All rights reserved.

A Novel Method to Handle the Effect of Uneven Sampling Effort in Biodiversity Databases

Science.gov (United States)

Pardo, Iker; Pata, María P.; Gómez, Daniel; García, María B.

2013-01-01

How reliable are results on spatial distribution of biodiversity based on databases? Many studies have evidenced the uncertainty related to this kind of analysis due to sampling effort bias and the need for its quantification. Despite that a number of methods are available for that, little is known about their statistical limitations and discrimination capability, which could seriously constrain their use. We assess for the first time the discrimination capacity of two widely used methods and a proposed new one (FIDEGAM), all based on species accumulation curves, under different scenarios of sampling exhaustiveness using Receiver Operating Characteristic (ROC) analyses. Additionally, we examine to what extent the output of each method represents the sampling completeness in a simulated scenario where the true species richness is known. Finally, we apply FIDEGAM to a real situation and explore the spatial patterns of plant diversity in a National Park. FIDEGAM showed an excellent discrimination capability to distinguish between well and poorly sampled areas regardless of sampling exhaustiveness, whereas the other methods failed. Accordingly, FIDEGAM values were strongly correlated with the true percentage of species detected in a simulated scenario, whereas sampling completeness estimated with other methods showed no relationship due to null discrimination capability. Quantifying sampling effort is necessary to account for the uncertainty in biodiversity analyses, however, not all proposed methods are equally reliable. Our comparative analysis demonstrated that FIDEGAM was the most accurate discriminator method in all scenarios of sampling exhaustiveness, and therefore, it can be efficiently applied to most databases in order to enhance the reliability of biodiversity analyses. PMID:23326357

Survey research with a random digit dial national mobile phone sample in Ghana: Methods and sample quality.

Science.gov (United States)

L'Engle, Kelly; Sefa, Eunice; Adimazoya, Edward Akolgo; Yartey, Emmanuel; Lenzi, Rachel; Tarpo, Cindy; Heward-Mills, Nii Lante; Lew, Katherine; Ampeh, Yvonne

2018-01-01

Generating a nationally representative sample in low and middle income countries typically requires resource-intensive household level sampling with door-to-door data collection. High mobile phone penetration rates in developing countries provide new opportunities for alternative sampling and data collection methods, but there is limited information about response rates and sample biases in coverage and nonresponse using these methods. We utilized data from an interactive voice response, random-digit dial, national mobile phone survey in Ghana to calculate standardized response rates and assess representativeness of the obtained sample. The survey methodology was piloted in two rounds of data collection. The final survey included 18 demographic, media exposure, and health behavior questions. Call outcomes and response rates were calculated according to the American Association of Public Opinion Research guidelines. Sample characteristics, productivity, and costs per interview were calculated. Representativeness was assessed by comparing data to the Ghana Demographic and Health Survey and the National Population and Housing Census. The survey was fielded during a 27-day period in February-March 2017. There were 9,469 completed interviews and 3,547 partial interviews. Response, cooperation, refusal, and contact rates were 31%, 81%, 7%, and 39% respectively. Twenty-three calls were dialed to produce an eligible contact: nonresponse was substantial due to the automated calling system and dialing of many unassigned or non-working numbers. Younger, urban, better educated, and male respondents were overrepresented in the sample. The innovative mobile phone data collection methodology yielded a large sample in a relatively short period. Response rates were comparable to other surveys, although substantial coverage bias resulted from fewer women, rural, and older residents completing the mobile phone survey in comparison to household surveys. Random digit dialing of mobile

Survey research with a random digit dial national mobile phone sample in Ghana: Methods and sample quality.