26 results
Search Results
2. CannibiSenS: an on-demand rapid screen for THC in human saliva.
- Author
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Churcher, Nathan Kodjo Mintah, Dhamu, Vikram Narayanan, and Prasad, Shalini
- Subjects
SALIVA ,CANNABIDIOL ,SURFACE plasmon resonance ,SUBSTANCE abuse - Abstract
Management of substances that possess high potential for abuse requires a comprehensive understanding of the temporal effects of a corresponding volume of intake. Cannabis is deemed as one of the most widely used drugs in the United States and studies related to the primary psychoactive compound present in it, Δ-9-tetrahydrocannabinol (THC), have revealed that it causes adverse health effects. In this study, we present a field-deployable electrochemical sensing system that can detect THC at the 5 ng mL
−1 cut-off level with a dynamic range of 0.1–100 ng mL−1 in human saliva. Considering the complexity of the human saliva matrix, the specificity study demonstrated selectivity towards THC with minimum interactions with ethanol and cannabidiol (CBD). Surface Plasmon Resonance (SPR) has been implemented to visualize and validate the capture probe as a means for THC detection. A robust, compatible binary classifier model has been shown in this work to effectively group samples into THC+ (high) and THC− (low) groups from human saliva with an accuracy greater than 90% considering a limited dataset. Hence, we demonstrate the potential of an innovative end-to-end system to effectively regulate cannabis use and prevent substance abuse in our surroundings. [ABSTRACT FROM AUTHOR]- Published
- 2023
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- View/download PDF
3. Conversion of plastic waste into high-value lubricants: techno-economic analysis and life cycle assessment.
- Author
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Cappello, Vincenzo, Sun, Pingping, Zang, Guiyan, Kumar, Shishir, Hackler, Ryan, Delgado, Hernan E., Elgowainy, Amgad, Delferro, Massimiliano, and Krause, Theodore
- Subjects
PRODUCT life cycle assessment ,PLASTIC scrap ,HIGH density polyethylene ,CIRCULAR economy ,MONETARY incentives ,PLASTIC recycling ,LUBRICATION & lubricants - Abstract
Given the low recycling rate of plastic waste in the United States due to low economic incentives, it is of great interest to develop a technology to upgrade plastic waste with favorable economics. Plastic upcycling to valuable chemicals could ensure a circular economy for plastics and reduce the environmental burden caused by their end use cycle and disposal. A conceptual facility to convert 250 metric ton (MT) per day of plastic waste was modeled; the main product was a high-quality liquid (HQL) with a similar performance to polyalphaolefin (PAO) lubricants. The modeled process had a lubricant yield of up to 90% based on the experimental results at the laboratory scale. Techno-economic analysis (TEA) and life cycle assessment (LCA) were also performed to evaluate the process economics and its environmental impact. By using a mixture of colored and natural high-density polyethylene (HDPE), the production cost was in the range of $0.6–$1.98 per kg of lubricant, depending on the operating conditions. The life cycle emissions were in the range of 0.48–1.2 kg
CO kg2e Lub −1 showing, for the best case scenario, a 52% reduction relative to the emissions for petroleum lubricants, and a 74% reduction relative to the emissions for PAO lubricants. The impacts of the lubricant yield, the catalyst amount, and reaction time were evaluated, and their effect on the final production cost was discussed. [ABSTRACT FROM AUTHOR]- Published
- 2022
- Full Text
- View/download PDF
4. Developments toward a low-cost approach for long-term, unattended vapor intrusion monitoring.
- Author
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Patel, Sanjay V. and Tolley, William K.
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POLLUTION ,ENVIRONMENTAL monitoring ,POLLUTANTS ,POLLUTION risk assessment ,POLLUTION & economics ,ECOLOGICAL restoration monitoring ,GAS chromatography ,MATHEMATICAL models - Abstract
There are over 450 000 sites contaminated by chemicals in the US. This large number of contaminated sites and the speed of subsurface migration of chemicals pose considerable risk to nearby residences and commercial buildings. The high costs for monitoring around these sites stem from the labor involved in placing and replacing the passive sorbent vapor samplers and the resultant laboratory analysis. This monitoring produces sparse data sets that do not track temporal changes well. To substantially reduce costs and better track exposures, less costly, unattended systems for monitoring soil gases and vapor intrusion into homes and businesses are desirable to aid in the remediation of contaminated sites. This paper describes progress toward the development of an inexpensive system specifically for monitoring vapor intrusion; the system can operate repeatedly without user intervention with low detection limits (1 × 10
−9 , or 1 part-per-billion). Targeted analytes include chlorinated hydrocarbons (dichloroethylene, trichloroethane, trichloroethylene, and perchloroethylene) and benzene. The system consists of a trap-and-purge preconcentrator for vapor collection in conjunction with a compact gas chromatography instrument to separate individual compounds. Chemical detection is accomplished with an array of chemicapacitors and a metal-oxide semiconductor combustibles sensor. Both the preconcentrator and the chromatography column are resistively heated. All components are compatible with ambient air, which serves as the carrier gas for the gas chromatography and detectors. [ABSTRACT FROM AUTHOR]- Published
- 2014
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- View/download PDF
5. Detection and classification of fentanyl and its precursors by surface-enhanced Raman spectroscopy.
- Author
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Mirsafavi, Rustin, Moskovits, Martin, and Meinhart, Carl
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RAMAN spectroscopy ,FENTANYL ,VIBRATIONAL spectra ,CHEMICAL precursors ,MICROFLUIDIC devices ,NARCOTICS ,PARTIAL least squares regression - Abstract
Fentanyl and its analogs have been at the center of the opioid epidemic currently wreaking havoc in the United States. One major element in the opioid crisis is the growing number of clandestine fentanyl labs being reported by enforcement agencies. The development of new analytical methods for detecting and identifying fentanyl and its congeners is among the useful tools in our goal to limit the use of this dangerous family of narcotics. Herein we describe an analytical technique using surface-enhanced Raman spectroscopy (SERS) and a microfluidic device, for detecting fentanyl and two of its chemical precursors, despropionylfentanyl (4ANPP) and N-phenethyl-4-piperidinone (NPP). The vibrational spectra of this family of analytes are very similar, making them difficult to distinguish by traditional means. In addition to taking advantage of the sensitivity provided by SERS, we developed a chemometric approach utilizing a hierarchical partial least squares-discriminant analysis algorithm that allowed us to distinguish spectra that possess many similar features. [ABSTRACT FROM AUTHOR]
- Published
- 2020
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6. Nanoparticle modification of microfluidic cell separation for cancer cell detection and isolation.
- Author
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Zhou, Yun, Dong, Ziye, Andarge, Hermella, Li, Wei, and Pappas, Dimitri
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CELL separation ,EARLY detection of cancer ,CANCER cells ,MICROFLUIDIC devices ,SILICA nanoparticles ,CELL lines - Abstract
Cancer is a major health problem in the United States with extremely high mortality. The detection and isolation of cancer cells are becoming increasingly important for cancer diagnosis. We describe a microfluidic device modified with silica nanoparticles to enhance the isolation of cancer cells using affinity separation. The isolation of seven different cancer cell lines spiked into liquid biopsies was demonstrated and compared with unmodified separation devices. Cancer cells were isolated using CD71 which has already been demonstrated to be a widespread "net" for capturing cancer cells of any phenotype as the affinity target. The capture efficiency of our nanoparticle (NP)-modified HB chip showed significant differences compared with the normal HB chip, exhibiting an average increase of 16%. The cell enrichment increased by a factor of 2 over unmodified chips. Patient-derived ALL cells, COG-LL-332, were spiked into blood with concentrations ranging from 1% to 20% of total leukocytes, and isolated with the purity of 41%–65%. The results of this study demonstrated that the increase of cell–chip interactions after nanoparticle modification improved capture efficiency and capture purity, and can be applied to a wide range of cell separations. [ABSTRACT FROM AUTHOR]
- Published
- 2020
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- View/download PDF
7. A simple but highly sensitive and selective colorimetric and fluorescent probe for Cu2 aqueous mediaElectronic supplementary information (ESI) available: Further experimental results and the characterization of compounds (NMR, HRMS spectra). See DOI: 10.1039/c0an00682c
- Author
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Yamin Li, Xiaoling Zhang, Baocun Zhu, Juan Xue, Zhi Zhu, and Weihong Tan
- Subjects
COPPER ions ,FLUORESCENT probes ,METAL quenching ,COLORIMETRIC analysis ,NUCLEAR magnetic resonance spectroscopy - Abstract
In this paper, CN-DPAwas prepared as an effective colorimetric and fluorescent probe for copper ions (Cu2) in aqueous solution. It exhibits good sensitivity and selectivity for Cu2ꋷ other metal ions both in aqueous solution and on a simple colorimetric paper-made test kit. Upon addition of Cu2, a remarkable color change from purple to colorless was easily observed by the naked eye, and a fluorescence quenching was also determined. Furthermore, CN-DPAcan be used to quantitatively detect Cu2. The linear range was 0â5 μM determined by absorption spectrometry. All these selective and sensitive results indicate that CN-DPAcould meet the selective requirements for biomedical and environmental application and be sensitive enough to detect Cu2 environmental water samples, even in drinking water, which has a limit of 20 μM defined by the U.S. Environmental Protection Agency. [ABSTRACT FROM AUTHOR]
- Published
- 2011
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- View/download PDF
8. Paul Bohn, University of Notre Dame, USA.
- Subjects
EDITORS ,UNIVERSITIES & colleges - Abstract
The Analystprofiles the new Editor for the Americas, Paul Bohn from the University of Notre Dame. [ABSTRACT FROM AUTHOR]
- Published
- 2007
9. 2009 spring conferences.
- Subjects
MEETINGS ,LABORATORIES ,CONFERENCES & conventions - Abstract
The article offers information on the conference to be held in the U.S. in March 2009 including annual meeting on laboratory science, American Physical Society (APS) meeting and 237th American Chemical Society (ACS) National Meeting & Exposition.
- Published
- 2009
10. Study of analyte dissociation and diffusion in laser-induced plasmas: implications for laser-induced breakdown spectroscopyPlasma-Analyte Interaction Working Group (PAIWG) is a collaborative effort of the University of Florida (USA), Federal Institute of Material Research and Testing (BAM) in Berlin (Germany), and ISAS-Institute for Analytical Sciences in Dortmund (Germany), jointly funded by NSF (Grant #CHE-0822469) and DFG.
- Author
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Prasoon K. Diwakar, Sebastian Groh, Kay Niemax, and David W. Hahn
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DISSOCIATION (Chemistry) ,DIFFUSION ,LASER-induced breakdown spectroscopy ,INDUCTIVELY coupled plasma atomic emission spectrometry ,HYDROGEN ,MASS transfer - Abstract
Plasma–particle interactions are explored through the introduction of single microdroplets into laser-induced plasmas. Both spectroscopic analysis and direct imaging of analyte atomic emission are used to provide insight into the various fundamental processes, namely desolvation, atomization, and atomic diffusion. By doping the 50 µm droplets with Lu, Mg or Ca, the analyte excitation temperature and the ion-to-neutral emission ratio are explored as a function of plasma residence time following breakdown. The data suggest a change in the local plasma conditions about the analyte atoms around 15–20 µs following breakdown, which may be interpreted as an overall transition from localized (i.e.perturbed) plasma conditions to the global (i.e.bulk) plasma conditions. A direct assessment of the hydrogen atomic diffusion coefficient following analyte desolvation reveals a value of 1.7 m2s−1in the first 250–500 ns. This value is in good overall agreement with a theoretical analysis and with an analytical treatment of a surface source of hydrogen atoms. In contrast, calcium emission is only observed beyond about 1 µs, with a diffusion coefficient at least an order of magnitude below the hydrogen value. The temporal H and Ca emission data suggest that water vaporizes first, leaving an ever increasing Ca analyte concentration until finally, with nearly all water desorbed, the Ca fraction is vaporized. Overall, the data support the conclusion that finite time-scales of heat and mass transfer play an important role in localized plasma perturbations in the vicinity of the analyte, which has important implications for the LIBS analyte signal. [ABSTRACT FROM AUTHOR]
- Published
- 2010
- Full Text
- View/download PDF
11. Cell lysis and DNA extraction of gram-positive and gram-negative bacteria from whole blood in a disposable microfluidic chip.
- Author
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Madhumita Mahalanabis, Hussam Al-Muayad, M. Dominika Kulinski, Dave Altman, and Catherine M. Klapperich
- Subjects
CELL death ,DNA ,GRAM-positive bacteria ,GRAM-negative bacteria ,MICROFLUIDICS ,INTEGRATED circuits ,SOLID phase extraction - Abstract
Sepsis caused by gram positive and gram negative bacteria is the leading cause of death in noncoronary ICUs and the tenth leading cause of death in the United States. We have developed a microfluidic sample preparation platform for rapid on-chip detection of infectious organisms for point-of-care diagnostics. The microfluidic chips are made of a robust thermoplastic and can be easily multiplexed for high throughput applications. Bacteria are lysed on-chip viahybrid chemical/mechanical method. Once lysed, the bacterial DNA is isolated using a microscale silica bead/polymer composite solid-phase-extraction (SPE) column. Lysis was confirmed using off-chip real time PCR. We isolated and detected both gram-negative (Escherichia coli) and gram-positive (Bacillussubtilisand Enterococcus faecalis)bacterial genomic DNA from microliter scale spiked whole human blood samples. The system performs better for gram-negative bacteria than it does for gram-positive bacteria, with limits of detection at 102CFU/ml and 103–104CFU/ml, respectively. Total extraction times are less than one hour and can be further decreased by altering the channel geometry and pumping configuration. [ABSTRACT FROM AUTHOR]
- Published
- 2009
12. Colorimetric Hg2+detection with a label-free and fully DNA-structured sensor assembly incorporating G-quadruplex halvesElectronic supplementary information (ESI) available: method for LOD determination, control experiments testing possible influences of Hg2+on the peroxidase activities of hemin and the complex formed between hemin and a G-quadruplex. See DOI: 10.1039/b908018j
- Author
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Na Lu, Congying Shao, and Zhaoxiang Deng
- Subjects
COLORIMETRY ,DNA ,MERCURY ,MOLECULAR recognition ,CHEMICAL detectors ,CONTAMINATION of drinking water ,NUCLEOTIDE sequence ,QUADRUPLEX nucleic acids - Abstract
A sensitive and fully DNA-structured ion sensor was built by integrating polyT sequences for highly selective Hg2+recognitions and two flanking G-quadruplex halves for allosteric signal transductions. The construction of this sensor was very easy that allowed a cost-effective detection of Hg2+with a limit of detection of 4.5 nM, which was lower than the 10 nM toxic level for drinkable water as regulated by the US's EPA. The strategy employed for the construction of this sensor may be further extended to other sensors through a rational structural fusion between re-engineered aptameric and enzymic DNA sequences. [ABSTRACT FROM AUTHOR]
- Published
- 2009
- Full Text
- View/download PDF
13. Initial performance metrics of a new custom-designed ArF excimer LA-ICPMS system coupled to a two-volume laser-ablation cellPresented at the 2008 Winter Conference on Plasma Spectrochemistry, Temecula, CA, USA, January 7–12, 2008.
- Author
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Wolfgang Müller, Michael Shelley, Pascal Miller, and Sergey Broude
- Subjects
INDUSTRIAL lasers ,LASER ablation ,UNITED States on television - Abstract
A new custom-built excimer (193 nm) laser-ablation system with two-volume laser-ablation cell coupled to a quadrupole ICPMS is described, which combines rapid (10000 cps/ppm for mid-high m/z, 55 μm, 5 Hz). An application of reconstructing medieval Pb exposure highlights the need for rapid signal washout in unravelling strongly varying Pb peaks in well-preserved archaeological tooth enamel. [ABSTRACT FROM AUTHOR]
- Published
- 2009
- Full Text
- View/download PDF
14. Coordination chemistry and biology of chelators for the treatment of iron overload disorders.
- Author
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Paul V. Bernhardt
- Subjects
IRON chelates - Abstract
Treatment of the medical condition generally referred to as iron overload through the delivery of chelators has recently received a major boost. In 2005 Novartis gained FDA approval for the drug deferasirox, which may be taken orally. Until this time most patients with Fe overload have had to endure long periods of subcutaneous infusions of the orally ineffective drug desferrioxamine (desferal) which has led to major problems with patient compliance. An effective Fe chelator must possess a number of properties for it to be able to complex Fe in vivo and be excreted intact. This Perspective will provide an overview of the current state of chelators for Fe overload; both those currently approved and those undergoing preclinical development. [ABSTRACT FROM AUTHOR]
- Published
- 2007
- Full Text
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15. Association of acrylamide hemoglobin biomarkers with chronic obstructive pulmonary disease in the general population in the US: NHANES 2013-2016.
- Author
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Liu S, Ben X, Liang H, Fei Q, Guo X, Weng X, Wu Y, Wen L, Wang R, Chen J, and Jing C
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- Adult, Aged, Aged, 80 and over, Biomarkers blood, Female, Humans, Male, Middle Aged, United States, Acrylamide blood, Hemoglobins metabolism, Nutrition Surveys methods, Pulmonary Disease, Chronic Obstructive blood
- Abstract
Background : Acrylamide is a well-known potential carcinogenic compound formed as an intermediate in the Maillard reaction during heat treatment, mainly from high-temperature frying, and is found in baked goods and coffee, as well as resulting from water treatment, textiles and paper processing. The effects of acrylamide on lung disease in humans remains unclear. We aimed to investigate the association between blood acrylamide and glycidamide and chronic obstructive pulmonary disease (COPD) in the United States of America (U.S.) population using PROC logistic regression models. Results : 2744 participants aged 20 to 80 from the 2013-2016 National Health and Nutrition Examination Survey (NHANES) were enrolled. After adjusting for demographic data, health factors and serum cotinine, the ratio of HbGA to HbAA (HbGA/HbAA) significantly increased the risk of COPD ( P for trend = 0.022). The odds ratio (OR) with a 95% confidence interval (95% CI) for HbGA/HbAA in the third tile was 2.45 (1.12-5.31), compared with the lowest tile. The restricted cubic spline (RCS) curve showed a positive linear correlation between the log (HbGA/HbAA) and the risk of COPD ( P = 0.030). Conclusion : The ratio of glycidamide and acrylamide (HbGA/HbAA) was associated with COPD. This association was more prominent in males, obese individuals, people with a poverty income ratio (PIR) < 1.85 or people who never exercise. However, null associations were observed between HbAA, HbGA and HbAA + HbGA, and COPD.
- Published
- 2021
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16. Regulations applicable to plant food supplements and related products in the European Union.
- Author
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Silano V, Coppens P, Larrañaga-Guetaria A, Minghetti P, and Roth-Ehrang R
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- Consumer Product Safety legislation & jurisprudence, Food Labeling legislation & jurisprudence, Herbal Medicine, Humans, Phytotherapy adverse effects, United States, Dietary Supplements adverse effects, Dietary Supplements analysis, European Union, Legislation, Food, Plant Preparations adverse effects, Plant Preparations chemistry, Plants, Edible adverse effects, Plants, Edible chemistry
- Abstract
This paper deals with the current regulatory and legal settings of traditional plant food supplements and herbal medicinal products in the European Union (EU). Marketing of botanicals in foods and food supplements in the EU is subject to several provisions of food law, which cover aspects of safety, production, labelling and product composition, including the use of additives and maximum levels of contaminants and residues. However, due to limited harmonization at the EU level, specific national regulations adopted at a Member State level also apply and mutual recognition is the mechanism through which such products can be marketed in EU countries other than those of origin. Unlike food supplements, marketing of traditional herbal medicinal products is regulated by an ad hoc Directive (i.e. Directive 2004/24/EC) covering in detail all the relevant aspects of these products, including a facilitated registration procedure at national level. However, by distinguishing traditional herbal medicinal products from plant food supplements and establishing selective marketing modalities for these two product categories, the EU has been confronted with implementation difficulties for traditional herbal medicinal products and a lack of homogeneity in the regulatory approaches adopted in different EU Member States. In fact, currently the nature of the commercial botanical products made available to consumers as traditional medicinal products or food supplements, depends largely on the EU Member State under consideration as a consequence of how competent National Authorities and manufacturing companies interpret and apply current regulations rather than on the intrinsic properties of the botanical products and their constituents. When the EU approach is compared with approaches adopted in some non-European countries to regulate these product categories, major differences become evident.
- Published
- 2011
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17. Passive ammonia monitoring in the United States: comparing three different sampling devices.
- Author
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Puchalski MA, Sather ME, Walker JT, Lehmann CM, Gay DA, Mathew J, and Robarge WP
- Subjects
- Calibration, Environmental Monitoring instrumentation, Limit of Detection, Linear Models, Models, Chemical, Reproducibility of Results, United States, Air Pollutants analysis, Air Pollution analysis, Ammonia analysis, Environmental Monitoring methods
- Abstract
The need for ambient gaseous ammonia (NH(3)) measurements has increased in the last decade as reactive NH(3) concentrations and deposition fluxes show little change even with tightening standards on nitrogen oxides (NO(x)) emissions. Currently, there are several networks developing methods for adding NH(3) measurements in the U.S. Gaseous NH(3) measurements will provide scientists and policymakers data which can be used to estimate ecosystem inputs, validate air quality models including trends and regional variability, and evaluate changes to the environment based on additional emission reduction requirements and estimates of critical nitrogen load exceedances. The passive samplers described in this paper were deployed in duplicate or triplicate and collocated with annular denuders or continuous instruments to determine their accuracy. The samplers assessed included the Adapted Low-Cost Passive High Absorption (ALPHA), Radiello(®), and Ogawa passive samplers. The median relative percent differences (MRPD) between the reference method and passive samplers for the ALPHA, Radiello(®) and Ogawa were -2.4%, -37% and -44%, respectively. The precision between duplicate samplers for the ALPHA and Ogawa samplers, was 7% and 6%, respectively. Triplicate Radiello(®) precision was assessed using the coefficient of variation (CV). The CV for the Radiello(®) samplers was 10%. This article discusses the statistical results from these studies.
- Published
- 2011
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18. A new USP Class VI-compliant substrate for manufacturing disposable microfluidic devices.
- Author
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Kuo JS, Ng L, Yen GS, Lorenz RM, Schiro PG, Edgar JS, Zhao Y, Lim DS, Allen PB, Jeffries GD, and Chiu DT
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- Biocompatible Materials chemistry, Methacrylates chemistry, Microscopy, Electron, Scanning, Polyurethanes chemistry, Spectrophotometry, Ultraviolet, Substrate Specificity, Surface Properties, United States, Commerce instrumentation, Equipment Design instrumentation, Microfluidic Analytical Techniques instrumentation, Microfluidics instrumentation, Pharmacopoeias as Topic standards
- Abstract
As microfluidic systems transition from research tools to disposable clinical-diagnostic devices, new substrate materials are needed to meet both the regulatory requirement as well as the economics of disposable devices. This paper introduces a UV-curable polyurethane-methacrylate (PUMA) substrate that has been qualified for medical use and meets all of the challenges of manufacturing microfluidic devices. PUMA is optically transparent, biocompatible, and exhibits high electroosmotic mobility without surface modification. We report two production processes that are compatible with the existing methods of rapid prototyping and present characterizations of the resultant PUMA microfluidic devices.
- Published
- 2009
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- View/download PDF
19. Equivalency of a personal dust monitor to the current United States coal mine respirable dust sampler.
- Author
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Page SJ, Volkwein JC, Vinson RP, Joy GJ, Mischler SE, Tuchman DP, and McWilliams LJ
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- Inhalation Exposure analysis, Occupational Exposure analysis, United States, Air Pollutants, Occupational analysis, Coal Mining, Dust analysis, Environmental Monitoring instrumentation
- Abstract
The United States National Institute for Occupational Safety and Health, through an informal partnership with industry, labor, and the United States Mine Safety and Health Administration, has developed and tested a new instrument known as the Personal Dust Monitor (PDM). The new dust monitor is an integral part of the cap lamp that coal miners normally carry to work and provides continuous information about the concentration of respirable coal mine dust within the breathing zone of that individual. Previous laboratory testing demonstrated that there is a 95% confidence that greater than 95% of individual PDM measurements fall within +/-25% of reference measurements. The work presented in this paper focuses on the relationship between the PDM and respirable dust concentrations currently measured by a coal mine dust personal sampler unit utilizing a 10 mm Dorr-Oliver nylon cyclone. The United Kingdom Mining Research Establishment instrument, used as the basis for coal mine respirable dust standards, had been designed specifically to match the United Kingdom British Medical Research Council (BMRC) criterion. The personal sampler is used with a 1.38 multiplier to convert readings to the BMRC criterion. A stratified random sampling design incorporating a proportionate allocation strategy was used to select a sample of mechanized mining units representative of all US underground coal mines. A sample of 180 mechanized mining units was chosen, representing approximately 20% of the mechanized mining units in production at the time the sample was selected. A total of 129 valid PDM/personal sampler dust sample sets were obtained. A weighted linear regression analysis of this data base shows that, in comparison with the personal sampler, the PDM requires a mass equivalency conversion multiplier of 1.05 [95% C.I.=(1.03, 1.08)] when the small intercept term is removed from the analysis. Removal of the intercept term results in a personal sampler-equivalent concentration increase of 2.9% at a PDM measurement of 2.0 mg m(-3).
- Published
- 2008
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20. Nanomaterials and the environment: uses, methods and measurement.
- Author
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Carl Englert B
- Subjects
- Particle Size, Surface Properties, United States, United States Environmental Protection Agency, United States Food and Drug Administration, Environmental Monitoring methods, Nanostructures
- Abstract
Nanotechnology has emerged as a field of science and engineering which offers many new product possibilities and potential solutions for a variety of problems. Nanomaterials come in many shapes and forms and contribute to potential products that do everything from sense analytes on a molecular level to function as self cleaning surfaces. With new and significant applications, it is likely that nanomaterial containing products may replace many of the products we use on a daily basis, leading to an increased presence of these materials in the environment. This will result in new needs and requirements from detection tools. It is likely that the analytical methods used to monitor nanomaterials in the environment will be very different than those used in risk assessment and exposure studies. This paper briefly outlines the history, impacts, and uses of nanomaterials and discusses possible methods of detection and quantification for environmental samples. The discussions in this article are specific to those matrices relating to wastewaters and sludge.
- Published
- 2007
- Full Text
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21. Trends analysis of ambient 8 hour ozone and precursor monitoring data in the south central U.S.
- Author
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Sather ME and Cavender K
- Subjects
- United States, Environmental Monitoring statistics & numerical data, Ozone analysis
- Abstract
For the south central U.S., lower tropospheric ozone pollution has been a persistent and challenging problem. This paper provides long-term trends analyses of the ozone and precursor monitoring data collected over the past 20 years in four south central U.S. cities. The results of these analyses should be useful to air quality scientists, managers, planners, and modelers in assessing the effectiveness of ozone pollution control strategies being implemented or being planned for the future. Results of the data analyses show that all areas have monitored significant decreases in ozone and precursor concentrations over the past 20 years, especially in El Paso, Texas. Continuing challenges include the reduction of the percentage of time that monitors record 8 hour ozone concentrations over the U.S. 8 hour ozone standard, and the future control of highly reactive volatile organic compounds.
- Published
- 2007
- Full Text
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22. The US National Cancer Institute's natural products repository; origins and utility.
- Author
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Brown EC and Newman DJ
- Subjects
- United States, Biological Products, National Institutes of Health (U.S.)
- Abstract
The US National Cancer Institute's natural products collection program has been running since 1986 and over the years the materials collected and processed have been stored in a repository that as a result of initial planning, has permitted the establishment of a national resource that is now being utilized as a drug discovery tool for any disease of interest to the NIH by researchers world-wide. This paper describes the history of the program.
- Published
- 2006
- Full Text
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23. Evaluation of the NIOSH draft method 5525 for determination of the total reactive isocyanate group (TRIG) for aliphatic isocyanates in autobody repair shops. National Institute for Occupational Safety and Health.
- Author
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Bello D, Streicher RP, and Woskie SR
- Subjects
- Automobiles, Hydrogen-Ion Concentration, Reproducibility of Results, Sensitivity and Specificity, United States, Air Pollution, Indoor analysis, Isocyanates analysis, National Institute for Occupational Safety and Health, U.S. legislation & jurisprudence, Occupational Exposure
- Abstract
This paper evaluates the performance of the NIOSH draft method 5525 for analysis of monomeric and TRIG aliphatic isocyanates in autobody repair shops. It was found that an optimized pH gradient enhanced noticeably the resolution and, therefore, identification of aliphatic isocyanates. Samples proved to be very stable for at least a year when stored at -13 degrees C in the freezer, and no major stability problems were found for the MAP reagent. The detector response factor RSD for selected MAP ureas was 40% in the fluorescence (FLD), 3% in the UV at 254 nm (UV254), and 1% in the UV at 370 nm (UV370). The mean FLD/UV254 and UV254/UV370 detector response ratios of standards were 31.7 (RSD = 37.8) and 17.1 (RSD = 5.4), respectively. The FLD/UV254 ratio in bulks varied from 0.41 to 1.97 times the HDI monomer ratio. The mean UV254/UV370 ratio in bulks was 16.1 (range 14.1 to 19.2, N = 38). Mean (range) recovery of 92 (91.2-93.2)% was found for the N3300 (isocyanurate) spiked on 25 mm quartz fiber filters in the range 0.07 to 2.2 microg NCO ml(-1). Mean (range) recovery for impingers was 100.7 (91.7-106.0)% for N3300 in the concentration range of 0.018 to 2.5 microg NCO ml(-1) and 81.0 (76.1-89.1)% for IPDI in the concentration range of 0.016 to 1.87 microg NCO ml(-1). Analytical method precision was 3.4% and mean bias 7.4% (range = 0-25%). The NIOSH draft method 5525 provides flexibility, enhanced sensitivity and specificity, powerful resolution, and very small compound-to-compound variability in the UV254, resulting in a more reliable identification and quantification of aliphatic isocyanates.
- Published
- 2002
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24. Public environmental information: access or excess?
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Sharpe M
- Subjects
- Benchmarking, Cultural Characteristics, Environmental Exposure, Environmental Monitoring, Europe, Humans, International Cooperation, Public Health, United States, Community-Institutional Relations, Environmental Pollution, Information Services, Public Opinion
- Abstract
Amongst the mass of academic papers and policy reports it is easy to forget that scientists and regulators are not the only ones concerned about the environment. The public has an interest too. Aided by modern technology and increasing legal rights, the man in the street has access to environmental information as never before. In this article we review recent developments in public assess and what these mean for 'the experts'.
- Published
- 1999
- Full Text
- View/download PDF
25. Elemental carbon-based method for occupational monitoring of particulate diesel exhaust: methodology and exposure issues.
- Author
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Birch ME and Cary RA
- Subjects
- Environmental Monitoring methods, Humans, National Institute for Occupational Safety and Health, U.S., Particle Size, United States, Air Pollutants, Occupational analysis, Carbon, Chemistry Techniques, Analytical methods, Occupational Exposure, Vehicle Emissions analysis
- Abstract
Diesel exhaust has been classified a probable human carcinogen, and the National Institute for Occupational Safety and Health (NIOSH) has recommended that employers reduce workers' exposures. Because diesel exhaust is a chemically complex mixture containing thousands of compounds, some measure of exposure must be selected. Previously used methods involving gravimetry or analysis of the soluble organic fraction of diesel soot lack adequate sensitivity and selectivity for low-level determination of particulate diesel exhaust; a new analytical approach was therefore needed. In this paper, results of investigation of a thermal-optical technique for the analysis of the carbonaceous fraction of particulate diesel exhaust are discussed. With this technique, speciation of organic and elemental carbon is accomplished through temperature and atmosphere control and by an optical feature that corrects for pyrolytically generated carbon, or "char,' which is formed during the analysis of some materials. The thermal-optical method was selected because the instrument has desirable design features not present in other carbon analysers. Although various carbon types are determined by the method, elemental carbon is the superior marker of diesel particulate matter because elemental carbon constitutes a large fraction of the particulate mass, it can be quantified at low levels and its only significant source in most workplaces is the diesel engine. Exposure-related issues and sampling methods for particulate diesel exhaust also are discussed.
- Published
- 1996
- Full Text
- View/download PDF
26. Summary of the NIOSH guidelines for air sampling and analytical method development and evaluation.
- Author
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Kennedy ER, Fischbach TJ, Song R, Eller PM, and Shulman SA
- Subjects
- Chemistry Techniques, Analytical methods, Humans, National Institute for Occupational Safety and Health, U.S., United States, Air Pollutants, Occupational analysis, Chemistry Techniques, Analytical standards, Occupational Health
- Abstract
Suggested guidelines for the development and evaluation of sampling and analytical methods for industrial hygiene monitoring have recently been published in a NIOSH technical report. These guidelines are based in part on various published approaches for method development and evaluation and serve as an attempt at a more unified experimental approach. This paper presents some salient features of this unified approach for method development and evaluation. The basic goal of the approach is to determine if the method under study meets the criterion to produce a result that fell within 25% of the true value 95 times out of 100 on average, although other factors of method performance are evaluated. The experiments proposed for the evaluation of method performance include determination of analytical recovery from the sampler, sampler capacity, storage stability of samples and effect of environmental factors. Evaluation criteria for the experimental data and procedures for the calculation of method bias, precision and accuracy are also included.
- Published
- 1996
- Full Text
- View/download PDF
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