Aerosol Analysis Using Handheld Raman Spectrometer: On-site Quantification of Trace Crystalline Silica in Workplace Atmospheres

2021 ◽  
Author(s):  
Shijun Wei ◽  
Belinda Johnson ◽  
Michael Breitenstein ◽  
Lina Zheng ◽  
John Snawder ◽  
...  
Keyword(s):  
Crystalline Silica ◽  
Breathing Zone ◽  
Sample Collection ◽  
Short Term ◽  
Limit Of Quantification ◽  
Measurement Capability ◽  
Matrix Interferences ◽  
Raman Spectrometer ◽  
Quantitative Measurements ◽  
Shift Analysis

Abstract A method for aerosol chemical analysis using handheld Raman spectrometer has been developed and its application to measurement of crystalline silica concentration in workplace atmosphere is described. The approach involves collecting aerosol as a spot sample using a wearable optical aerosol monitor, followed by direct-on-filter quantitative analysis of the spot sample for crystalline silica using handheld Raman spectrometer. The filter cassette of a commercially available optical aerosol monitor (designed to collect aerosol for post-shift analysis) was modified to collect 1.5-mm-diameter spot sample, which provided adequate detection limits for short-term measurements over a few tens of minutes or hours. The method was calibrated using aerosolized α-quartz standard reference material in the laboratory. Two Raman spectrometers were evaluated, one a handheld unit (weighing less than 410 g) and the other a larger probe-based field-portable unit (weighing about 5 kg). The lowest limit of quantification for α-quartz of 16.6 μg m−3 was obtained using the handheld Raman unit at a sample collection time of 1 h at 0.4 l min−1. Short-term measurement capability and sensitivity of the Raman method were demonstrated using a transient simulated workplace aerosol. Workplace air and personal breathing zone concentrations of crystalline silica of workers at a hydraulic fracturing worksite were measured using the Raman method. The measurements showed good agreement with the co-located samples analyzed using the standard X-ray powder diffraction (XRD) method, agreeing within 0.15–23.2% of each other. This magnitude of difference was comparable to the inter- and intra-laboratory analytical precision of established XRD and infrared methods. The pilot study shows that for silica-containing materials studied in this work it is possible to obtain quantitative measurements with good analytical figures of merit using handheld or portable Raman spectrometers. Further studies will be needed to assess matrix interferences and measurement uncertainty for several other types of particle matrices to assess the broader applicability of the method.

scholarly journals Evaluation of Saliva Stability for NMR Metabolomics: Collection and Handling Protocols

Metabolites ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 515
Author(s):  
Daniela Duarte ◽  
Beatriz Castro ◽  
Joana Leonor Pereira ◽  
Joana Faria Marques ◽  
Ana Luísa Costa ◽  
...  
Keyword(s):  
Metabolic Profile ◽  
Room Temperature ◽  
Clinical Laboratory ◽  
Sample Collection ◽  
Short Term ◽  
General Stability ◽  
Sample Stability ◽  
Choline Esters ◽  
Different Temperatures ◽  
Term Storage

Maintaining a salivary metabolic profile upon sample collection and preparation is determinant in metabolomics. Nuclear magnetic resonance (NMR) spectroscopy was used to identify metabolite changes during short-term storage, at room temperature (RT)/4 °C/−20 °C, and after sample preparation, at RT/4 °C (mimicking typical clinical/laboratory settings). Interestingly, significant metabolic inter-individual and inter-day variability were noted, probably determining sample stability to some extent. After collection, no changes were noted at −20 °C (at least for 4 weeks). RT storage induced decreases in methylated macromolecules (6 h); lactate (8 h); alanine (12 h); galactose, hypoxanthine, pyruvate (24 h); sarcosine, betaine, choline, N-acetyl-glycoproteins (48 h), while acetate increased (48 h). Less, but different, changes were observed at 4 °C, suggesting different oral and microbial status at different temperatures (with a possible contribution from inter-individual and inter-day variability), and identifying galactose, hypoxanthine, and possibly, choline esters, as potential general stability indicators. After preparation, addition of NaN3 did not impact significantly on saliva stabilization, neither at RT nor at 4 °C, although its absence was accompanied by slight increases in fucose (6.5 h) and proline (8 h) at RT, and in xylose (24 h) at 4 °C. The putative metabolic origins of the above variations are discussed, with basis on the salivary microbiome. In summary, after collection, saliva can be stored at RT/4 °C for up to 6 h and at −20 °C for at least 4 weeks. Upon preparation for NMR analysis, samples are highly stable at 25 °C up to 8 h and at 4 °C up to 48 h, with NaN3 addition preventing possible early changes in fucose, proline (6–8 h), and xylose (24 h) levels.

Short-term stability of free metanephrines in plasma and whole blood

2020 ◽  
Vol 58 (5) ◽  
pp. 753-757 ◽  
Author(s):  
Elisa Danese ◽  
Martina Montagnana ◽  
Claudio Brentegani ◽  
Giuseppe Lippi
Keyword(s):  
Whole Blood ◽  
Repeated Measures ◽  
Sample Collection ◽  
Short Term ◽  
Total Change ◽  
Term Stability ◽  
Before And After ◽  
Liquid Chromatography Tandem Mass ◽  
The Mean ◽  
The Stability

AbstractBackgroundAnalysis of plasma metanephrine (MN) and normetanephrine (NMN) with liquid chromatography tandem mass spectrometry (LC-MS/MS) is the gold standard for the screening of pheochromocytomas and paragangliomas (PPGLs). As scarce information is available on the stability of MNs in diagnostic samples, this study was aimed at analyzing the short-term stability of plasma free MNs in whole blood and plasma, using LC-MS/MS.MethodsThe stability of plasma MNs was evaluated after sample collection at 1, 2 and 3 h in whole blood, and at 2, 4 and 6 h in centrifuged samples. Both studies were performed while maintaining the samples at room temperature (RT) and at 4 °C. The ClinMass Complete Kit (Recipe, Munchen, Germany) was used for measuring MNs with LC-MS/MS (Nexera X2 UHPLC-4500MD Sciex). Differences from the baseline (T0) were assessed using repeated measures one-way ANOVA, Students’ paired t-test and a comparison of the mean percentage changes with the total change limit (TCL).ResultsStatistically significant differences from T0 were found for both MNs (p < 0.001) in whole blood stored at RT, and for NMN (p = 0.028) but not MN (p = 0.220) at 4 °C. The mean difference exceeded the TCL after 1 h and 3 h at RT for MN, and after 1 h at RT for NMN. Statistically significant differences from T0 were only observed in the plasma samples for NMN at RT (p = 0.012), but the variation was within the TCL.ConclusionsMN and NMN displayed different patterns of stability before and after centrifugation. Even short-time storage at RT in whole blood should hence be avoided.

Cortisol and β-endorphin responses to physical and psychological stressors in lambs

1997 ◽  
Vol 77 (4) ◽  
pp. 689-694 ◽  
Author(s):  
G. J. Mears ◽  
F. A. Brown
Keyword(s):  
Stress Responses ◽  
Plasma Cortisol ◽  
Plasma Concentrations ◽  
Sample Collection ◽  
Short Term ◽  
Psychological Stressors ◽  
Tail Docking ◽  
Cortisol Responses ◽  
Ram Lambs ◽  
Potential Use

Plasma cortisol, β-endorphin, T3 and T4 were determined in lambs before, during and after exposure to stress in order to evaluate the potential use of these hormones to objectively measure stress responses. Lambs were exposed to tail-docking, castration, weaning, isolation, and restraint stress. Twelve ewe and 24 ram lambs were assigned to the experiment, with 12 of the ram lambs surgically castrated when 3-wk old. Tail docking within 24 h of birth did not (P > 0.05) elevate either plasma cortisol or β-endorphin. Castration markedly elevated (P < 0.001) plasma cortisol and β-endorphin within 15 min of surgery. Both hormones were highly elevated for the first 4 h. Plasma cortisol returned to control levels by 24 h whereas β-endorphin was still elevated (P < 0.05) 24 h after castration. Plasma cortisol levels were elevated for the first 60 min following weaning (P < 0.005) and again at 24 h after dam removal (P < 0.001). Plasma β-endorphin was not elevated (P > 0.05) any time during the 72 h following weaning. Plasma cortisol (P < 0.001) and β-endorphin (P < 0.05) were elevated during the first 60 min following the start of 1 h of isolation. Results were similar for partial and total isolation. No effects of isolation were found for the next 23 h. Plasma cortisol (P < 0.005) was elevated during the first 30 min following 4 min of shearing-like restraint, whereas plasma β-endorphin was elevated only at 7 min (P < 0.05) after restraint began. No further effects of restraint were found prior to termination of sample collection at 24 h. None of the stressors employed affected plasma concentrations of T3 and T4. This study has shown that measurements of plasma cortisol and β-endorphin in blood samples obtained before, during and after stress are useful in assessing stress in lambs. The painful stressor, castration, induced marked and prolonged elevations of both hormones, whereas psychological stressors elicited graded, short-term cortisol responses and limited β-endorphin responses. Key words: Cortisol, β-endorphin, physical stress, psychological stress, lambs

scholarly journals The Carbon Isotope Ratio of Breath Is Elevated by Short and Long-Term Added Sugar and Animal Protein Intake in a Controlled Feeding Study

2021 ◽  
Vol 5 (Supplement_2) ◽  
pp. 1069-1069
Author(s):  
Diane O'Brien ◽  
Natasha Tasevska ◽  
Virag Sagi-Kiss ◽  
Susana A Palma-Duran ◽  
Brian Barrett ◽  
...  
Keyword(s):  
Carbon Isotope ◽  
Isotope Ratio ◽  
Carbon Isotope Ratio ◽  
Animal Protein ◽  
Sample Collection ◽  
Short Term ◽  
Added Sugar ◽  
Feeding Study ◽  
Short And Long Term

Abstract Objectives Objective biomarkers would help to clarify relationships between added sugar (AS) intake and chronic disease. A recent study identified the breath carbon isotope ratio (CIR) as a potential short-term AS biomarker. To further evaluate the biomarker potential of the breath CIR, we evaluate the effects of both short and longer-term intakes of AS in the context of normal dietary intake patterns, and also evaluate animal protein (AP), another dietary factor known to influence CIR. Methods We conducted a 15-d controlled feeding study of 100 adults (age 18–70, 55% women) in Phoenix, AZ. Participants were provided individualized diets that approximated habitual food intakes and recorded the time that all foods were consumed throughout each day. Three breath samples were collected on each of 3 nonconsecutive, randomly selected study days: one fasting sample, one “morning” sample (collected 10:00–14:00) and one “evening” sample (collected 14:00–20:00). We used a linear mixed model to evaluate the effects of AS and AP intake in each of 8 hours preceding collection of the breath sample (t1 = 0–1 hour prior, t2 = 1–2 hours prior, etc.). Besides daily intake, models also included 15-d mean AS and AP intake, as well as sex, age and BMI. Coefficients are presented as (β (SE), P). Results Mean (±SD) intakes of AS and AP in our study were 67 ± 34 and 73 ± 30 g/d, respectively. The breath CIR was increased by AS consumed 1–4 hours prior to sample collection (βt2 = 0.014 (0.005), P = 0.0025; βt3 = 0.0094 (0.004), P = 0.02; βt4 = 0.012 (0.005), P = 0.02) and AP consumed 3–6 hours prior to sample collection (βt4 = 0.012 (0.005), P = 0.03; βt5 = 0.0092 (0.004), P = 0.03; βt6 = 0.010 (0.006), P = 0.09). In addition, the breath CIR increased with higher 15-d intakes of both AS and AP (βAS = 0.012 (0.003), P &lt; 0.0001 and βAP = 0.014 (0.004), P = 0.0003, respectively). Conclusions Both short-term and longer-term intakes of AS and AP increased the breath CIR. Short-term AS intake had a more rapid effect on the breath CIR than short-term AP intake, although effects were of similar size. Furthermore, the size of short-term effects were similar to the size of long-term effects. Thus, breath CIR is influenced by both short and long-term intakes of AS and AP and could have potential for evaluating dietary patterns. Funding Sources This work was funded by NIH U01 CA197902.

scholarly journals Evaluation of Occupational Exposure to Silica Dust in Mining Workers in Eastern Iran

2019 ◽  
Vol 12 (1) ◽  
pp. 1-6 ◽  
Author(s):  
Farideh Golbabaei ◽  
Abdollah Gholami ◽  
Gholamheidar Teimori-Boghsani ◽  
Mehdi Yaseri ◽  
Mojtaba Kianmehr
Keyword(s):  
Occupational Safety ◽  
Cross Sectional Study ◽  
Silica Content ◽  
Crystalline Silica ◽  
Respirable Dust ◽  
Breathing Zone ◽  
Mining Operations ◽  
Cross Sectional ◽  
Silica Dust ◽  
Free Silica

Background and Objective: Silica dust is present in almost all mining operations and can cause various health problems such as silicosis in workers. The present study aimed to determine the total and respirable dust levels and the crystalline silica content of the soil in the breathing zone of workers in Iranian mines. Methods: This cross-sectional study was carried out in 2016-2017 on six Iranian silica mines. Dust sampling was performed according to the National Institute of Occupational Safety and Health (NIOSH) method No. 0600. The samples were collected from the respiratory zone of workers at 114 stations in different units of the mines. The silica content was measured using the standard NIOSH method No. 7601. The crystalline silica content in bulk samples collected from the soil was determined by using the X-Ray Diffraction (XRD) spectroscopy method. Results: The highest concentration of crystalline silica dust was 2.81±0.49 mg/m3 and was observed in the air of crushing unit of mine no. 6, and the lowest was 0.08±0.208 mg/m3 and was measured in the management/administration unit of mine no.1. The mean silica content in the solid surface of the mines was 91%. The total and respirable dust levels in all units of the mines except management/administration were higher than the permissible limit. The free silica content of all collected samples was substantially higher than the permissible limits, and in some cases, it was as much as 100 times above the standard level, which reflects the extremely high risk of working in these mines. Conclusion: Exposure of workers with crystalline silica dust in all units was higher than the standard recommended limits. It is imperative to adopt immediate measures based on technical, managerial, and personal protection solutions to reduce the exposure of workers to silica.

scholarly journals Fifth-Generation Digital Immunoassay for Prostate-Specific Antigen by Single Molecule Array Technology

2011 ◽  
Vol 57 (12) ◽  
pp. 1712-1721 ◽  
Author(s):  
David H Wilson ◽  
David W Hanlon ◽  
Gail K Provuncher ◽  
Lei Chang ◽  
Linan Song ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Radical Prostatectomy ◽  
Prostate Specific Antigen ◽  
Single Molecule ◽  
Specific Antigen ◽  
Analytical Performance ◽  
Response To Treatment ◽  
Serum Samples ◽  
Limit Of Quantification ◽  
Measurement Capability

BACKGROUND Measurement of prostate-specific antigen (PSA) in prostate cancer patients following radical prostatectomy (RP) has been hindered by the limit of quantification of available assays. Because radical prostatectomy removes the tissue responsible for PSA production, postsurgical PSA is typically undetectable with current assay methods. Evidence suggests, however, that more sensitive determination of PSA status following RP could improve assessment of patient prognosis and response to treatment and better target secondary therapy for those who may benefit most. We developed an investigational digital immunoassay with a limit of quantification 2 logs lower than current ultrasensitive third-generation PSA assays. METHODS We developed reagents for a bead-based ELISA for use with high-density arrays of femtoliter-volume wells. Anti-PSA capture beads with immunocomplexes and associated enzyme labels were singulated within the wells of the arrays and interrogated for the presence of enzymatic product. We characterized analytical performance, compared its accuracy with a commercially available test, and analyzed longitudinal serum samples from a pilot study of 33 RP patients. RESULTS The assay exhibited a functional sensitivity (20% interassay CV) &lt;0.05 pg/mL, total imprecision &lt;10% from 1 to 50 pg/mL, and excellent agreement with the comparator method. All RP samples were well within the assay measurement capability. PSA concentrations following surgery were found to be predictive of prostate cancer recurrence risk over 5 years. CONCLUSIONS The robust 2-log improvement in limit of quantification relative to current ultrasensitive assays and the validated analytical performance of the assay allow for accurate assessment of PSA status after RP.

scholarly journals Validation and Clinical Evaluation of a Novel Method To Measure Miltefosine in Leishmaniasis Patients Using Dried Blood Spot Sample Collection

2016 ◽  
Vol 60 (4) ◽  
pp. 2081-2089 ◽  
Author(s):  
A. E. Kip ◽  
H. Rosing ◽  
M. J. X. Hillebrand ◽  
S. Blesson ◽  
B. Mengesha ◽  
...  
Keyword(s):  
Venous Blood ◽  
Dried Blood Spot ◽  
Patient Specific ◽  
Pharmacokinetic Studies ◽  
Sample Collection ◽  
Limit Of Quantification ◽  
Simple Method ◽  
Linear Effect ◽  
Combination Treatments ◽  
Blood Spot

ABSTRACTTo facilitate future pharmacokinetic studies of combination treatments against leishmaniasis in remote regions in which the disease is endemic, a simple cheap sampling method is required for miltefosine quantification. The aims of this study were to validate a liquid chromatography-tandem mass spectrometry method to quantify miltefosine in dried blood spot (DBS) samples and to validate its use with Ethiopian patients with visceral leishmaniasis (VL). Since hematocrit (Ht) levels are typically severely decreased in VL patients, returning to normal during treatment, the method was evaluated over a range of clinically relevant Ht values. Miltefosine was extracted from DBS samples using a simple method of pretreatment with methanol, resulting in >97% recovery. The method was validated over a calibration range of 10 to 2,000 ng/ml, and accuracy and precision were within ±11.2% and ≤7.0% (≤19.1% at the lower limit of quantification), respectively. The method was accurate and precise for blood spot volumes between 10 and 30 μl and for Ht levels of 20 to 35%, although a linear effect of Ht levels on miltefosine quantification was observed in the bioanalytical validation. DBS samples were stable for at least 162 days at 37°C. Clinical validation of the method using paired DBS and plasma samples from 16 VL patients showed a median observed DBS/plasma miltefosine concentration ratio of 0.99, with good correlation (Pearson'sr= 0.946). Correcting for patient-specific Ht levels did not further improve the concordance between the sampling methods. This successfully validated method to quantify miltefosine in DBS samples was demonstrated to be a valid and practical alternative to venous blood sampling that can be applied in future miltefosine pharmacokinetic studies with leishmaniasis patients, without Ht correction.

Variability in snow-urine assays

1995 ◽  
Vol 73 (3) ◽  
pp. 427-432 ◽  
Author(s):  
P. J. White ◽  
R. A. Garrott ◽  
D. M. Heisey
Keyword(s):  
Dietary Intake ◽  
Urinary Metabolites ◽  
Accurate Estimate ◽  
Urine Samples ◽  
Total Variance ◽  
Sample Collection ◽  
Short Term ◽  
Urea Nitrogen ◽  
Measurement Variability ◽  
Dilution Effects

Urea nitrogen: creatinine ratios in snow urine have become popular for assessing the extent of winter nutritional deprivation in ungulates. During winter 1992 – 1993, we collected 10–17 sequential snow-urine samples (402 total) from 27 individually identifiable free-ranging adult female elk. Within-animal variance accounted for 91% of the total variance (351.66 mg2/dL2) in creatinine, 86% of the total variance (637.03 mg2/dL2) in urea nitrogen, and 82% of the total variance (0.56) in urea nitrogen: creatinine ratios. This substantial within-animal variability was unexpected and led to experiments that examined whether the variability was due to sample collection and measurement technique or actually reflected biological variability. Factors examined included dilution effects, measurement (assay) repeatability, and short-term (<24 h) within-animal constancy in metabolite excretion. No dilution effects were detected when the initial concentrations of snow-urine samples were diluted <75% with water. Measurement variability accounted for 0.78, 0.37, and 27.7% of the total variance in creatinine, urea nitrogen, and urea nitrogen: creatinine ratios, respectively. Within-animal metabolite excretion was reasonably constant within 24 h, suggesting that creatinine provides a valid index for comparing urinary metabolites. We conclude that variability in urea nitrogen: creatinine ratios due to dilution, measurement variability, and short-term temporal variability in metabolite excretion was small compared with the total within-animal variance. Urea nitrogen: creatinine ratios should provide an accurate estimate of the true ratios of these metabolites in an elk's bladder urine. However, the interpretation of urea nitrogen: creatinine ratios is often complex, since they reflect the immediate dynamics between fat depletion, protein catabolism, and dietary intake. Differences in ratios between collections may be partially due to variations in recent dietary intake or restriction, in addition to true differences in long-term nutritional status. The best method for statistically analyzing snow-urine data remains unresolved.

Development and Clinical Evaluation of a High-Throughput LC–MS/MS Assay for Vitamin B6 in Human Plasma and Serum

2020 ◽  
Author(s):  
Mark M Kushnir ◽  
Boya Song ◽  
Evelyn Yang ◽  
Elizabeth L Frank
Keyword(s):  
Clinical Evaluation ◽  
High Throughput ◽  
Vitamin B6 ◽  
Multiple Reaction Monitoring ◽  
Internal Standard ◽  
Analysis Time ◽  
Mode Analysis ◽  
Enzymatic Reactions ◽  
Sample Collection ◽  
Limit Of Quantification

Abstract Background Pyridoxal 5′-phosphate (PLP) is the primary circulatory form of vitamin B6, an essential cofactor for numerous biochemical enzymatic reactions. Conventional PLP analysis using high-performance liquid chromatography (HPLC) with fluorescence requires derivatization and long injection-to-injection time. Development of high-throughput LC–MS/MS assays is desirable. Methods Stable isotope labeled internal standard was added to aliquots of samples, proteins were precipitated using trichloroacetic acid, and supernatants were analyzed by multiple reaction monitoring using LC–MS/MS in positive ion mode. Analysis time for PLP was 3.0 min using single column HPLC separation and 2.4 min using alternating column regeneration (ACR). Clinical evaluation of the method included review of results (n = 102 386) from routine performance of the assay. Results The assay was linear to 500 nmol/L; limit of quantification was 5 nmol/L. Imprecision (CV) of the assay was &lt;5%. Equivalent performance was observed for single HPLC column and ACR. In 62% of routinely analyzed patient samples, PLP concentrations were within the reference interval; higher PLP concentrations were observed in samples from males than from females. Vitamin B6 deficiency was lowest in children and highest in elderly adults. Lower PLP concentrations were observed in samples collected during winter/spring than during summer/fall. We observed lower concentrations in plasma collected in lithium heparin tubes, suggesting PLP degradation caused by the anticoagulant. Conclusions This LC–MS/MS method allows PLP determination using simple sample preparation and short analysis time. We observed association of PLP concentrations with age, sex, and season of sample collection. Our data indicate that lithium heparin anticoagulant tubes reduce measured PLP concentration.

Slow Education From a Homeschooling Perspective

2021 ◽  
pp. 49-64
Author(s):  
Rozanne Dioso-Lopez
Keyword(s):  
Mass Distribution ◽  
Traditional Education ◽  
Time Constraints ◽  
Home Education ◽  
Children And Families ◽  
Short Term ◽  
Mass Data ◽  
Quantitative Measurements ◽  
Time Period ◽  
Slow Learning

This chapter explores one mother's perspective on homeschooling when there are no time constraints to learning. Home education provides an alternative to this fast-paced lifestyle. It is an antidote to a system that rewards conformity and provides stress to families and children. The home is where slow learning can thrive, thereby encouraging individuality, creativity, and curiosity. By abandoning the rush, families adapt to a natural rhythm for learning. Traditional education systems, mechanistic in their mass distribution design, have transformed learning into time-restricted activities, placing pressure and stress on children and families. Learning is short-term and its purpose is externally motivated. When learning is evaluated solely by quantitative measurements in a specified time period, the impetus for going deeper into a subject is eliminated or a curious interest in a subject is subverted. Mass data cannot be analyzed when individuals are assessed based on inherent qualities of true learning like transference of skills and knowledge, creativity, and curiosity.

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