Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 91
Filter
1.
J Forensic Sci ; 68(4): 1162-1177, 2023 Jul.
Article in English | MEDLINE | ID: mdl-37357497

ABSTRACT

The 4- Aminophenol (4-AP) colorimetric test is a fast, easy-to-use, and cost-effective presumptive assay of cannabis plant material producing different chromophores with THC-rich cannabis (blue color) and with CBD-rich cannabis (pink color). The main drawback of the 4-AP test is a brief observation window where the color rapidly changes to black, limiting the utility of the test. We now report for the first time, the identification of the product chromophores between 4-AP and CBD/THC as well as propose an explanation and a solution for the color degradation of the chromophores. The identification of the chromophores is provided by spectroscopic (UV-Vis), chromatography, and mass spectrometry (TLC and LC-QToF-MS). Oxidation of excess 4-AP (Reagent A) in the presence of NaOH (Reagent B) produces the black color observed for the previously reported 4-AP tests and reported in the literature. The adjustment of reactants concentrations and volumes of 4-AP:THC/CBD to a 1:1 ratio significantly reduces the black oxidation by-product and increases the observation window up to 2 h instead of the previously reported 5-10 min. For the first time, mass spectrometry and chromatography confirmed that the reaction of THC and CBD with 4-AP produced chromophores with m/z (M + H) = 420, consistent with proposed indophenol structures. The TLC method developed confirmed the separation between CBD and THC chromophores. The specificity of the test is also reported, showing false positive results for the presence of THC (blue color) for samples of thyme and oregano. LDA and SIMCA models showed that the optimized 4-AP procedure performs better than the previously reported 4-AP color test.


Subject(s)
Cannabidiol , Cannabinoids , Cannabis , Hallucinogens , Cannabis/chemistry , Cannabinoids/analysis , Aminophenols , Colorimetry , Dronabinol/analysis , Cannabidiol/analysis
2.
J Forensic Sci ; 68(5): 1504-1519, 2023 Sep.
Article in English | MEDLINE | ID: mdl-37310108

ABSTRACT

Synthetic opioids such as fentanyl account for over 71,000 of the approximately 107,000 overdose deaths reported in the United States in 2021. Fentanyl remains the fourth most identified drug by state and local forensic laboratories, and the second most identified drug by federal laboratories. The unambiguous identification of fentanyl-related substances (FRS) is challenging due to the absence or low abundance of a molecular ion in a typical gas chromatography-mass spectrometry (GC-MS) analysis and due to a low number of fragment ions that are similar among the many potential isomers of FRS. This study describes the utility of a previously reported gas chromatography-infrared (GC-IR) library for the identification of FRS within a blind, interlaboratory study (ILS) involving seven forensic laboratories. Twenty FRS reference materials, including those with isomer pairs in the library, were selected based on either their presence in the NIST library and/or some similarity of the mass spectra information produced. The ILS participants were requested to use the Florida International University (FIU) GC-MS and GC-IR libraries supplied by FIU to search for matches to their unknown spectra generated from in-house GC-MS and GC-IR analysis. The laboratories reported improvement in the positive identification of unknown FRS from ~75% using GC-MS alone to 100% correct identification using GC-IR analysis. One laboratory participant used solid phase IR analysis, which produced spectra incompatible with the vapor phase GC-IR library to generate a good comparison spectrum. However, this improved when searched against a solid phase IR library.


Subject(s)
Fentanyl , Humans , Gas Chromatography-Mass Spectrometry/methods , Mass Spectrometry , Isomerism , Spectrum Analysis
3.
Forensic Sci Int ; 349: 111735, 2023 Aug.
Article in English | MEDLINE | ID: mdl-37276771

ABSTRACT

The forensic comparison of glass aims to compare a glass sample of an unknown source with a control glass sample of a known source. In this work, we use multi-elemental features from Laser Ablation Inductively Coupled Plasma with Mass Spectrometry (LA-ICP-MS) to compute a likelihood ratio. This calculation is a complex procedure that generally requires a probabilistic model including the within-source and between-source variabilities of the features. Assuming the within-source variability to be normally distributed is a practical premise with the available data. However, the between-source variability is generally assumed to follow a much more complex distribution, typically described with a kernel density function. In this work, instead of modeling distributions with complex densities, we propose the use of simpler models and the introduction of a data pre-processing step consisting on the Gaussianization of the glass features. In this context, to obtain a better fit of the features with the Gaussian model assumptions, we explore the use of different normalization techniques of the LA-ICP-MS glass features, namely marginal Gaussianization based on histogram matching, marginal Gaussianization based on Yeo-Johnson transformation and a more complex joint Gaussianization using normalizing flows. We report an improvement in the performance of the Likelihood Ratios computed with the previously Gaussianized feature vectors, particularly relevant in their calibration, which implies a more reliable forensic glass comparison.

4.
J Forensic Sci ; 68(2): 629-637, 2023 Mar.
Article in English | MEDLINE | ID: mdl-36715133

ABSTRACT

A new, fast, and ultra-sensitive headspace sampling method using the Capillary Microextraction of Volatiles (CMV) device is demonstrated for the analysis of ignitable liquid residues (ILRs) in fire debris. This headspace sampling method involves the use of a heated can (60°C) to aid in the recovery of volatile organic compounds (VOCs) from medium and heavy petroleum distillates. Our group has previously reported the utility of CMV to extract gasoline at ambient temperature in less than 5 min in the field. This work evaluates the recovery and analysis of low mass loadings (tens of ng) of VOCs from charcoal lighter fluid, kerosene, and diesel fuel. Nonane, decane, undecane, tridecane, tetradecane, and pentadecane were selected for evaluation of recovery to represent these ILR classes. The face-down heated can headspace sampling technique was compared to the previously reported, non-heated, paper cup headspace sampling technique. Mass recovery improvements of 50%-200% for five of the six target compounds in diesel fuel were achieved compared to the non-heated sampling method. The average relative standard deviation (reported as % RSD) between the replicate trials decreased from an average of 28% to 6% when using the heated can method. Ignitable liquids were spiked onto burned debris in a live burn exercise and sampled using the heated can and paper cup headspace sampling techniques. The heated sampling technique reported here, for the first time, demonstrates an effective extraction method that when coupled to a portable GC-MS instrument allows for a sampling and analysis protocol in the field in less than 30 min.

6.
Front Med (Lausanne) ; 9: 815783, 2022.
Article in English | MEDLINE | ID: mdl-35280865

ABSTRACT

Multimorbidity has received much attention and there is a growing number of original studies. However, randomized controlled trials (RCTs) have failed to demonstrate effectiveness of interventions aimed at improving outcomes for patient with multimorbidity in primary care. The purpose of this article is to synthesize and analyze the most recent RCTs to identify the factors that may have contribute to the success or lack of success in order to draw lessons to inform further development in intervention research. A scoping review was conducted to include current up-to-date state-of-the-art studies in primary care published from 2019. Nine articles reporting on six RCTs studies were included in the review. The findings were mixed, with primary outcomes showing no differences between intervention and control groups in four of the six but differences in secondary outcomes in all six. All studies involved family practice patients but interventions took place at different sites, and the time between the beginning of the intervention and the time of evaluation of outcomes varied across studies. Authors reported issues regarding the need for training of care teams, the roles and composition of the teams, the selection of patients and implementation barriers of the complex interventions in trying contexts with not enough time for the changes required. The randomized controlled design may not be the best evaluation design given the complexity of the interventions, and alternative designs should be considered in which qualitative components are included. Further attention to outcome measures and to equity issues is recommended.

7.
Article in English | MEDLINE | ID: mdl-34924688

ABSTRACT

Consensus concentration values for seventeen (17) major and trace elements typically present in soda-lime glass manufactured using the "float " process and used in the quantitative analysis and forensic comparison of glass samples were determined using laser ablation (LA) micro sampling coupled to inductively coupled plasma mass spectrometry (ICP-MS). This is the first reporting of the chemical characterization of a new set of float glass intended for use as matrix-matched calibration standards in the forensic analysis and comparison of glass by LA-ICP-MS using a standard test method (ASTM E2927-16e1). Three Corning Float Glass Standards (CFGS) were manufactured at low, medium, and high concentrations of 32 elements typically encountered in float glass samples as found in forensic casework. This work describes an international collaboration among seven (7) laboratories to evaluate the homogeneity of the three glass materials and reports the consensus concentrations values of 17 elements at three concentration levels. Eight (8) sets of independent results from LA-ICP-MS analysis using the standard test method of analysis and one set of micro-X-ray Fluorescence Spectrometry (µXRF) data (using method ASTM E2926-17) resulted in typically <3% relative standard deviation (RSD) within each lab and < 5% RSDs among all labs participating in the study for the concentration ranges using sampling spots between 50 µm - 100 µm in diameter. These results suggest that the new calibration standards are homogeneous for most elements at the small sampling volumes (~ 90 µm deep by ~80 µm in diameter) reported and show excellent agreement among the different participating labs. Consensus concentration values are determined using a previously reported calibration standard (FGS 2) and checked with a NIST 1831 SRM®. A collaboration with National Institute of Standards and Technology (NIST) scientists to certify these glasses as SRMs, including the certification of the quantitative analysis of the minor and trace element content, for future distribution by NIST is ongoing.

8.
J Multimorb Comorb ; 11: 26335565211039780, 2021.
Article in English | MEDLINE | ID: mdl-34820337

ABSTRACT

CONTEXT: Interventions for people with multimorbidity have obtained mixed results. We aimed to document the long-term effect of an intervention for people with multimorbidity. METHODS: 284 patients (18-80 years) presenting three or more chronic conditions were recruited from seven family medicine groups in the Saguenay-Lac St-Jean region, Quebec, Canada. The patient-centered intervention was based on motivational approach and self-management support. Outcomes were evaluated in a one-year pre-post study design with questionnaires that included the Health Education Questionnaire (heiQ), the Self-Efficacy for Managing Chronic Diseases, the Veteran RAND-12 Health Survey (VR-12), the EuroQoL 5-Domains questionnaire, the Kessler six item Psychological Stress Scale, and measures of smoking habit, physical activity, healthy eating and alcohol consumption. Subgroup analyses by age, number of conditions, sex, and income were also conducted. RESULTS: The heiQ domain of emotional wellbeing improved significantly. Improvement was also observed for the VR-12 and the K6. Among the health behaviours, only healthy eating was improved. Subgroup analyses in this exploratory study suggest that younger patients, those with lower number of chronic conditions or higher incomes may respond better in relation to self-management, health status and health behaviours. CONCLUSION: One year after the intervention, participants significantly improved a variety of outcomes. Subgroup analyses suggest that younger patients, those with lower number of chronic conditions or higher incomes may respond better in relation to self-management, health status and health behaviours. This suggests that future interventions should be tailored to patients' characteristics including age, sex, income and number of conditions.

9.
Forensic Chem ; 222021 Mar.
Article in English | MEDLINE | ID: mdl-34485765

ABSTRACT

Seventeen laboratories participated in three interlaboratory exercises to assess the performance of refractive index, micro X-ray Fluorescence Spectroscopy (µXRF), and Laser Induced Breakdown Spectroscopy (LIBS) data for the forensic comparison of glass samples. Glass fragments from automotive windshields were distributed to the participating labs as blind samples and participants were asked to compare the glass samples (known vs. questioned) and report their findings as they would in casework. For samples that originated from the same source, the overall correct association rate was greater than 92% for each of the three techniques (refractive index, µXRF, and LIBS). For samples that originated from different vehicles, an overall correct exclusion rate of 82%, 96%, and 87% was observed for refractive index, µXRF, and LIBS, respectively. Special attention was given to the reporting language used by practitioners as well as the use of verbal scales and/or databases to assign a significance to the evidence. Wide variations in the reported conclusions exist between different laboratories, demonstrating a need for the standardization of the reporting language used by practitioners. Moreover, few labs used a verbal scale and/or a database to provide a weight to the evidence. It is recommended that forensic practitioners strive to incorporate the use of a verbal scale and/or a background database, if available, to provide a measure of significance to glass forensic evidence (i.e., the strength of an association or exclusion).

10.
Ann Fam Med ; 19(2): 126-134, 2021.
Article in English | MEDLINE | ID: mdl-33685874

ABSTRACT

PURPOSE: To measure the effectiveness of a 4-month interdisciplinary multifaceted intervention based on a change in care delivery for patients with multimorbidity in primary care practices. METHODS: A pragmatic randomized controlled trial with a mixed-methods design in patients aged 18 to 80 years with 3 or more chronic conditions from 7 family medicine groups (FMGs) in Quebec, Canada. Health care professionals (nurses, nutritionists, kinesiologists) from the FMGs were trained to deliver the patient-centered intervention based on a motivational approach and self-management support. Primary outcomes: self-management (Health Education Impact Questionnaire); and self-efficacy. SECONDARY OUTCOMES: health status, quality of life, and health behaviors. Quantitative analyses used multi-level mixed effects and generalized linear mixed models controlling for clustering within FMGs. We also conducted in-depth interviews with patients, family members, and health care professionals. RESULTS: The trial randomized 284 patients (144 in intervention group, 140 in control group). The groups were comparable. After 4 months, the intervention showed a neutral effect for the primary outcomes. There was significant improvement in 2 health behaviors (healthy eating with odds ratios [OR] 4.36; P = .006, and physical activity with OR 3.43; P = .023). The descriptive qualitative evaluation revealed that the patients reinforced their self-efficacy and improved their self-management which was divergent from the quantitative results. CONCLUSIONS: Quantitatively, this intervention showed a neutral effect on the primary outcomes and substantial improvement in 2 health behaviors as secondary outcomes. Qualitatively, the intervention was evaluated as positive. The combination of qualitative and quantitative designs proved to be a good design for evaluating this complex intervention.


Subject(s)
Interprofessional Relations , Multimorbidity , Patient-Centered Care , Quality of Life , Adolescent , Adult , Aged , Aged, 80 and over , Chronic Disease , Female , Humans , Male , Middle Aged , Primary Health Care
11.
J Comorb ; 10: 2235042X20965283, 2020.
Article in English | MEDLINE | ID: mdl-33110764

ABSTRACT

CONTEXT: Multimorbidity is frequently seen in primary care. We aimed to identify and analyze publications on multimorbidity, including those that most influenced this field. METHOD: A bibliometric analysis of publications from 2005 to 2019 in the PubMed database containing "multimorbidity" or "multi-morbidity" identified with the tool iCite. We analyzed the number of publications, total citations, the article-level metric Relative Citation Ratio (RCR), type of study, and journals with the most cited articles. RESULTS: The number of publications using "multimorbidity" has continuously increased since 2005 (2005-2009: 138; 2010-2014: 823; 2015-2019: 3068). The median number of total citations per article was 3. The median RCR was 1.04. Articles with RCR at or above the 97th percentile (RCR = 7.43) were analyzed in detail (n = 104). In 34 publications of this subgroup (33%), the word multimorbidity was used but was not the subject of study. The remaining top 70 publications included 32 observational studies, 22 reviews, five guideline statements, three analysis papers, two randomized trials, three qualitative studies, two measurement development reports, and one conceptual framework development report. The publications were produced by authors from 32 countries. They were published in 37 different journals, ranging from one to four articles in the same journal. CONCLUSIONS: We found a continuous increase in the number of publications about multimorbidity since 2005. However, our study suggests that the numbers should be considered only a general trend because multimorbidity was not the main subject in 33% of publications in a subgroup of 104 analyzed in detail.

12.
Forensic Sci Int Synerg ; 2: 404-415, 2020.
Article in English | MEDLINE | ID: mdl-33385139

ABSTRACT

This review paper covers the forensic-relevant literature in paint and glass evidence from 2016 to 2019 as a part of the 19th Interpol International Forensic Science Managers Symposium. The review papers are also available at the Interpol website at: https://www.interpol.int/content/download/14458/file/Interpol%20Review%20Papers%202019.pdf.

13.
Forensic Sci Int ; 301: 426-434, 2019 Aug.
Article in English | MEDLINE | ID: mdl-31229846

ABSTRACT

Computing the likelihood ratio (LR), as a measure of weight of evidence, has traditionally been difficult for multi-element evidence. A solution based on multivariate random effects models has been adopted by the forensic community but suffers from instability and has a tendency toward extreme values. This problem is magnified by increasing the number of variables. In this study, we consider reducing the dimensionality of the problem using principal component analysis (PCA) and a post-hoc calibration step suggested by van Es et al. [1] and evaluate the performance of this method using multi-element data collected from electrical tapes with up to 18 elements measured. A set of 90 tapes known to originate from different sources were analyzed by LA-ICP-MS. We used additive log-ratio transformation with respect to the signal of 208Pb to transform the 18-dimensional data. This transformation altered the scale of the signals and more importantly, the transformed signals exhibited characteristics similar to a normal distribution. We used scores of the first five principal components (PCs) as input to the LR formula given by Aitken and Lucy [2] where we assumed multivariate normal between-sources distribution (LR MVN) to compare the tapes. We observed that the calculated LRs were extremely positive and negative and did not conform with the definition of well-calibrated LRs. Thus, we used the post-hoc calibration method given by van Es et al. [1] to calibrate the likelihood ratios. The calibrated LRs were obtained within an appropriate range. Five scenarios, each related to the number of principal components used to compare the samples formed part of this study. The first scenario made the comparisons using only the first PC, the second scenario used the first two PCs together and so on. The last scenario, LR5, used 5 PCs for the comparisons. Comparing the results of these 5 scenarios provided an understanding around sensitivity of the method based on the percentage of information used for the comparisons. The lowest false exclusion (Type I) and false inclusion (Type II) error rates were obtained for LR5 scenario in comparison to all the other scenarios. False inclusion and false exclusion error rates of 3.7% and 2.2% were reported by using only 5 out of 17 PCs. False exclusion error rates of 2.2% indicated that only two same-source comparisons had LR<1. The proposed method overcomes the problem of using highly-dimensional data for the comparisons, while using a high percentage of information present in the original data.

14.
BMC Fam Pract ; 20(1): 53, 2019 04 22.
Article in English | MEDLINE | ID: mdl-31010425

ABSTRACT

BACKGROUND: Limited studies exist on successful interventions for patients with multimorbidity. Even more limited is the knowledge on how socioeconomic factors have an impact on these interventions. The objective of this study was to analyze the effect of a multidisciplinary self-management intervention among patients with multimorbidity and the impact of socioeconomic factors on the results. METHODS: Secondary data analysis limited to multimorbid patients from of a pragmatic randomized trial evaluating an intervention that included patients (18 to 75 yrs.) from eight primary care practices in Quebec, Canada. The intervention included self-management support and patient-centred motivational approaches. Self-management was evaluated using the Health Education Impact Questionnaire (heiQ) which measures eight different domains. Changes in heiQ were analyzed following the three-month intervention with univariate and multivariate logistic regressions. RESULTS: Participants with three or more chronic conditions (n = 281), randomized to intervention or control groups, were included in this analysis. The effect of the intervention on the likelihood of an improvement in self-management was significant in six heiQ domains in the univariate analysis (Odd ratio; 95% CI): Health-directed behaviour (2.03; 1.16-3.55), Emotional well-being (1.97; 1.05-3.68), Self-monitoring and insight (2.35; 1.02-5.40), Constructive attitudes and approaches (2.91; 1.45-5.84), Skill and technique acquisition (1.96; 1.13-3.39), and Health services navigation (2.52; 1.21-5.21). After controlling for age and gender the results remained essentially the same. After additional adjustments for family income, education and self-perceived financial status, the likelihood of an improvement was no longer significant in the domains Emotional well-being and Self-monitoring and insight. CONCLUSIONS: The intervention produced significant improvements in multimorbid patients for most domains of self-management. Socioeconomic factors had a minor impact on the results. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT01319656.


Subject(s)
Economic Status , Educational Status , Income , Multiple Chronic Conditions/therapy , Patient-Centered Care , Self-Management/education , Adult , Age Factors , Aged , Female , Health Behavior , Humans , Logistic Models , Male , Mental Health , Middle Aged , Motivation , Multimorbidity , Multivariate Analysis , Patient Education as Topic , Randomized Controlled Trials as Topic , Self-Management/methods , Sex Factors , Social Participation , Socioeconomic Factors
15.
Health Psychol ; 38(9): 783-790, 2019 Sep.
Article in English | MEDLINE | ID: mdl-31021126

ABSTRACT

OVERVIEW: The presence of multiple concurrent medical conditions (also known as multimorbidity) is now a common phenomenon, hence the importance of its measurement. OBJECTIVE: The purpose of this paper is to review the multimorbidity measures that have been published in the literature to date and that are available for use in future research studies. METHOD: Two main groups of measures of multimorbidity could be distinguished. The first group of measures is constituted by a simple count from various lists of chronic conditions. The second group of measures introduces a weighting for included chronic conditions thus creating a "weighted index" of multimorbidity. These groups are not mutually exclusive as the list of medical conditions in some weighted indices can be used as a list of conditions without weighting. This article includes a review of the multimorbidity literature to date that has reported these groups of measurements, showing the variety of existing measurements and highlighting their differences to provide an overview of the possibilities that are available to a researcher intending to measure multimorbidity. CONCLUSION: Finally, we outline some guidelines for the choice of a measurement of multimorbidity for research studies. We hope that this review of the existing literature will help inform the careful use of these tools by researchers moving forward. In addition to this review, it is advised that readers attempt to keep updated on the ever-increasing multimorbidity literature. (PsycINFO Database Record (c) 2019 APA, all rights reserved).


Subject(s)
Multimorbidity/trends , Chronic Disease , Humans
16.
Talanta ; 186: 655-661, 2018 Aug 15.
Article in English | MEDLINE | ID: mdl-29784417

ABSTRACT

Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry (LA-ICP-MS) has been shown to be an excellent technique for the discrimination of glass originating from different sources and for the association of glass originating from the same source. Typically, a match criterion is used to compare the elemental profile of the known sample to a questioned sample and if the glass samples are determined to "match" this may be followed by the use of a verbal scale to report the forensic practitioner's conclusion. This approach has several disadvantages: a fixed match criterion suffers from the "fall-off-the-cliff effect," the rarity of an elemental profile is not taken into account, and the use of a verbal scale to assign a weight of evidence may be considered as subjective and can vary by examiner. An alternative approach includes the use of a continuous likelihood ratio that provides a quantitative measure of the value of the evidence in support of any hypothesis and accounts for the rarity of an elemental profile through the use of a glass database. In the present study, two glass databases were used to evaluate the performance of the likelihood ratio; the first database includes 420 automotive windshield samples, while the second database includes 385 glass samples from casework. The multivariate kernel model was used for the calculation of the likelihood ratio. However, this model led to unreasonably large (or small) likelihood ratios. Thus, a calibration step, using the Pool Adjacent Violators (PAV) algorithm, was necessary in order to limit the likelihood ratio to reasonable values. The calibrated likelihood ratio presented rates of misleading evidence of <1.5% (for LRs<1 when objects came from the same source), and of <1.0% (for LRs>1 when objects came from different sources), which improved over the analogous ASTM false inclusion and false exclusion rates previously reported. In addition, the likelihood ratio limited the magnitude of the misleading evidence, providing only weak to moderate support for the incorrect hypothesis. Finally, most of the pairs found to present LR>1 when objects originated from different sources were explained by similarity of manufacturer of the glass source.

17.
Talanta ; 186: 670-677, 2018 Aug 15.
Article in English | MEDLINE | ID: mdl-29784419

ABSTRACT

Milk has been reported as one of the most adulterated foodstuffs in the developed and developing world. One way to detect adulteration is to determine whether the country of origin on the label could be the actual country of origin. Such profiling may be accomplished through the use of elemental analysis techniques, however this is a preliminary study and this goal is not yet met. In this study, a laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) method was developed for the analysis of solid milk powder and compared to k0-instrumental neutron activation analysis (k0-INAA) for a reference milk material (IAEA-153) as well as several milk samples from different countries. The analytical figures of merit for both the LA-ICP-MS and the k0-INAA analysis are reported. Precision of ~ 10% RSD or better was achieved for most elements for both techniques and bias of ~ 10% was achieved for both techniques for most elements with LA-ICP-MS producing lower limits of detection (~ 1 mg/kg) for Sr. The comparison of LA-ICP-MS to k0-INAA showed overlap of the 95% confidence intervals for all comparison samples. A total of 68 authentic milk powder samples representing 5 different countries (Argentina, Russia, Singapore, Slovenia, and the United States) were analyzed to determine whether multivariate elemental differences between the countries were sufficiently larger than within country differences in order to visualize groupings by country. Principle component analysis (PCA) using Na, Mg, Ca, Rb, and Sr show different groups for the United States, Argentina, Singapore, and Slovenia samples of limited representation for each country. However the large number and geographic distribution of samples from Russia were not able to be distinguished from the samples from the United States and Slovenia.


Subject(s)
Lasers , Milk/chemistry , Powders/analysis , Animals , Mass Spectrometry , Principal Component Analysis
18.
Anal Chim Acta ; 1014: 27-40, 2018 Jul 19.
Article in English | MEDLINE | ID: mdl-29523249

ABSTRACT

A novel phenyl modified PDMS (PhPDMS) sol-gel adsorption phase was developed for use with the capillary microextraction of volatiles (CMV) device, and determined to provide significant enhancement in BTEX recoveries when sampling trace (ng) amounts of these volatiles at ambient conditions. The previously reported reusable PDMS-CMV device has been demonstrated to rapidly and efficiently extract target compound's vapors in forensic and environmental applications. An improved recovery for VOCs was achieved with a cryofocusing system while extracting at -10 °C, but it was found to be impractical for field sampling. This report details a modification to the CMV's chemistry, by the successful introduction of phenyl groups to the PDMS sol-gel adsorption phase, allowing enhanced performance at ambient extraction conditions. Higher average recoveries, determined through a broad concentration range, were demonstrated for PhPDMS-CMV over its original PDMS-CMV, from cans simulating a closed space set-up. Within 7.8 (±10%) and 3.5 (±6%) folds higher for benzene and toluene, respectively and 2 (±2%) folds for ethylbenzene and xylenes. Significant higher retaining capabilities were demonstrated also at the more challenging set-up, simulating an open space environment. Whereas, benzene had completely breakthrough the PDMS-CMV, its reliable detection was still confirmed with PhPDMS-CMV pumping at 2 L or 6 L air, concentration dependent. At least 50 folds (±26%) more toluene was retained with PhPDMS-CMV at 6 L air than with PDMS-CMV. The enhanced overall performance lead to determination of trace LODs with the new CMV of 0.002, 0.00035 and 0.00015 ppm for benzene, toluene, ethyl benzene and xylenes, respectively. As proof of concept, for the first time solvent extraction is presented for the new CMV as an alternative to thermal desorption extraction. Extraction efficiencies of 60% for TEX, and lower concentration dependent for benzene, were demonstrated with the ease and rapid application of 100 µL acetone through the device. The improvements described in this study continues to build on the potential for the use of the reusable new CMV device by expanding its possible potential applications for fast and sensitive air sampling of VOCs. The solvent extraction step may offer compatibility with LC-based systems.

19.
J Forensic Sci ; 63(1): 66-79, 2018 Jan.
Article in English | MEDLINE | ID: mdl-28542948

ABSTRACT

This study applies Raman microspectroscopy to differentiate the chemical components in printing inks of different brands, colors, and type using the 532 nm and 785 nm excitation wavelengths. Spectra were collected from 319 inks (78 inkjet, 76 toner, 79 offset, and 86 intaglio) representing various colors. Comparisons were performed to calculate discrimination capability percentages for each ink type. Overall, Raman microspectroscopy differentiates according to the following hierarchy: intaglio (96%), inkjet (92%), offset (90%), and toner (61%). The ability of Raman microspectroscopy to differentiate between same-colored inks from different brands was dependent on the color and ink analyzed. Based on ink color, the discrimination capability ranged from 75 to 94% (inkjet), 0 to 86% (toner), and 0 to 77% (offset). Copper phthalocyanine was detected in cyan inks and various intaglio inks, while carbon black was identified in black inkjet, offset, and intaglio inks.

20.
CMAJ Open ; 5(3): E729-E733, 2017 Sep 25.
Article in English | MEDLINE | ID: mdl-28947426

ABSTRACT

BACKGROUND: Various data sources may be used to document the presence of chronic medical conditions. This study examined the agreement between self-reported and health administrative data. METHODS: A randomly selected cohort of participants aged 25-75 years recruited by telephone from the general population of Quebec reported on the presence of 1 or more chronic conditions from a candidate list of 12 conditions: diabetes, hypertension, thyroid disorder, any cardiac disease, cancer diagnosis in the previous 5 years (including melanoma but excluding other skin cancers), asthma, osteoarthritis, rheumatoid arthritis or lupus, osteoporosis, chronic obstructive pulmonary disease, intestinal disease and hypercholesterolemia. We also used health administrative data from Quebec's universal health insurance provider to identify participants' chronic conditions. Unique identifiers allowed linkage of both data sources to the individual participant. The frequencies of the 12 conditions and the prevalence of multimorbidity (≥ 2, ≥ 3 and ≥ 4 conditions) were analyzed for each data source. RESULTS: We analyzed data for 1177 participants (mean age 53 [standard deviation 12.4] yr; 684 women [58.1%]). We found low (but varied) agreement between the 2 data sources, with the poorest agreement for hypercholesterolemia (κ = 0.04 [95% confidence interval (CI) 0.01 to 0.07]) and the best for diabetes (κ = 0.82 [95% CI 0.76 to 0.88]). Prevalence estimates of multimorbidity obtained with health administrative data were lower than those obtained with self-reported data regardless of the operational definition used. Most participants with multimorbidity were identified by self-report. INTERPRETATION: We argue for the use of self-reported chronic conditions in the study of multimorbidity, as health administrative data based on the billing system in Quebec seem to underestimate the prevalence of many chronic conditions, which results in biased estimates of multimorbidity.

SELECTION OF CITATIONS
SEARCH DETAIL