Historically, blood alcohol concentration (BAC) studies utilized a 1% concentration of the preservative sodium fluoride (NaF), leaving an information gap supporting usage of lower concentrations of ...NaF to preserve ethanol. As many forensic laboratories utilize Becton, Dickinson and Company 6‐mL gray‐top tubes (0.25% NaF), statistical comparisons were conducted to determine whether significant differences exist between BAC values obtained from 6‐mL tubes versus 10‐mL tubes (1% NaF). Whole blood was spiked at three concentrations, (0.04, 0.08, and 0.15 g/100 mL) and aliquoted into tubes at “low,” “medium,” and “high” fill volumes. Tubes were split into refrigerated or ambient storage and analyzed after 1, 3, 5, 7, and 30 days, using headspace gas chromatography. Each 6‐mL and 10‐mL tube pair, prepared, stored, and analyzed under identical conditions, was compared by t‐test (95% confidence level). For refrigerated tubes, 32 of 45‐tube pairs did not reject the null hypothesis (that 6‐mL and 10‐mL tubes yield equivalent BACs), and 31 of 45 ambient stored tube pairs did not reject the null hypothesis. Analysis of variance (ANOVA) found no significant differences between 6‐mL and 10‐mL gray‐top tubes for 0.04 and 0.15 g/100 mL concentrations over 30 days; significant differences were observed for 0.08 g/100 mL concentration tubes, which warrants further study. Paired t‐tests of grouped samples found no significant differences between 6‐mL and 10‐mL tubes at any concentration.
Acute Behavioral Tolerance to Alcohol Comley, R. Edward; Dry, Matthew J
Experimental and clinical psychopharmacology,
02/2020, Volume:
28, Issue:
1
Journal Article
Peer reviewed
Although the strength of the effect produced by alcohol is generally dose dependent, its effect on behavior cannot be reliably predicted by the dose alone because the dose effect has been shown to ...vary. Acute behavioral tolerance is a rapid decrease in the dose effect of alcohol, seen to occur within the duration of a single dose. Numerous research paradigms have been used to examine acute behavioral tolerance, across an array of different behavioral measures. We have reviewed studies that used a research paradigm appropriate to test for acute behavioral tolerance. The primary aim was to examine the different paradigms that have been used to identify what empirical evidence of the effect has been found. The additional aims were to identify domains of behavior in which acute tolerance has been shown to occur and ascertain which conditions have been shown to influence it. Findings of acute tolerance were prevalent. Seven different research paradigms were identified, and each found evidence of acute behavioral tolerance in at least 1 study. The effect was not uniform across all behavioral measures. Subjective measures reliably showed the effect, but objective measures of behavior were less reliable, providing evidence that particular aspects of task performance are more sensitive to acute tolerance than others. The dose effect of alcohol for behavioral measures is often shown to decrease within the duration of a single dose. Investigations into, and considerations of, the effects of alcohol on behavior need to consider temporal changes in the dose effect.
Public Health Significance
The effect of alcohol on behavioral measures has often been found to decrease within the duration of a dose. This decrease is not universal and was seen to vary between different behavioral measures. Subjective measures more reliably show acute tolerance than objective measures, and this difference between behavioral domains raises concerns regarding issues like binge drinking and drinking and driving. Guidance for responsible drinking and future research into the effects of alcohol should consider the demonstrated decrease in the effect of alcohol and the variability in the dose effect between different domains of behavior.
Addition of ethanol in human serum albumin decelerates the protein dynamic process upon temperature jump.
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•Addition of ethanol in human serum albumin decelerates the protein ...dynamics.•The effect of alcohol is weakened at slightly hyperthermic temperatures.•Understanding the role of alcohol in perturbing HSA at the molecular level.
The addition of ethanol at concentrations ≤ 1.0 vol% in human serum albumin (HSA) at the physiological concentration (ca. 47 mg L−1) does not influence the secondary structure but decelerates the protein dynamic process of HSA upon thermal stimulus probed by fluorescent temperature jump technique. The biological implication may be that inebriated persons are less sensitive to environmental stimuli because their HSA molecules may act more slowly when interacting with chemicals in the blood. This result provides an alternative perspective on the role of alcohol in perturbing the biological function of HSA at the molecular level.
We estimate the distribution of random parameters in a distributed parameter model with unbounded input and output for the transdermal transport of ethanol. The underlying model is a diffusion ...equation with input: blood alcohol concentration and output: transdermal alcohol concentration. We reformulate the dynamical system so that the random parameters are treated as additional space variables. When the distribution to be estimated is absolutely continuous with a joint density, estimating the distribution is equivalent to estimating the diffusivity in a multi-dimensional diffusion equation. Well-established finite dimensional approximation schemes, functional analytic based convergence arguments, optimization techniques, and computational methods may be employed. We use our technique to estimate a bivariate normal distribution based on data for multiple drinking episodes from a single subject.
We develop an approach to estimate a blood alcohol signal from a transdermal alcohol signal using physics-informed neural networks (PINNs). Specifically, we use a generative adversarial network (GAN) ...with a residual-augmented loss function to estimate the distribution of unknown parameters in a diffusion equation model for transdermal transport of alcohol in the human body. We design another PINN for the deconvolution of the blood alcohol signal from the transdermal alcohol signal. Based on the distribution of the unknown parameters, this network is able to estimate the blood alcohol signal and quantify the uncertainty in the form of conservative error bands. Finally, we show how a posterior latent variable can be used to sharpen these conservative error bands. We apply the techniques to an extensive dataset of drinking episodes and demonstrate the advantages and shortcomings of this approach.
Background
The development of a transdermal alcohol biosensor could represent a tremendous advance toward curbing problematic drinking. But several factors limit the usefulness of extant transdermal ...technology, including relatively lengthy delays between blood alcohol concentration (BAC) and transdermal alcohol concentration (TAC), as well as the large/bulky designs of currently available transdermal sensors (e.g., ankle monitors). The current research examined the lag time between BAC and TAC using a prototype of BACtrack Skyn—a new‐generation wrist‐worn transdermal sensor featuring a compact design and smartphone integration.
Methods
Participants (N = 30) received either a dose of alcohol (target BAC 0.08%) or a nonalcoholic beverage in the laboratory while wearing both the AMS SCRAM ankle monitor and a Skyn prototype. Participants were monitored in the laboratory until breath alcohol concentration (BrAC) dropped below 0.025%.
Results
Device failure rates for Skyn prototypes were relatively high (18 to 38%) compared with nonprototype SCRAM devices (2%). Among participants with usable data, both Skyn‐ and SCRAM‐measured TAC showed strong correlations with BrAC, and both Skyn and SCRAM devices detected alcohol within 30 minutes of first alcohol administration. Skyn‐measured TAC peaked over 1 hour earlier than SCRAM‐measured TAC (54 versus 120 minutes after peak BrAC, respectively), and time‐series models suggested that, on average across all measured portions of the BrAC curve, Skyn TAC lagged behind BrAC by 24 minutes, whereas SCRAM TAC lagged behind BrAC by 69 minutes—all differences statistically significant at p < 0.001.
Conclusions
Results provide preliminary evidence for the validity of a new‐generation wrist‐worn transdermal sensor under controlled laboratory conditions and further suggest favorable properties of this sensor as they pertain to the latency of transdermal alcohol detection. The prototype version of Skyn employed here displayed a higher failure rate compared with SCRAM, and, in future, more reliable and robust Skyn prototypes will be required suitable to field testing across diverse environmental conditions.
This study compared data collected via a new‐generation transdermal wrist sensor with data from the SCRAM transdermal ankle monitor during laboratory alcohol‐administration. Transdermal alcohol concentration (TAC), as detected using both sensors, showed a strong correlation with breath alcohol concentration (BrAC). Lag times between BrAC and TAC were approximately half the duration when TAC was measured using the new‐generation sensor versus SCRAM. Failure rates of new‐generation sensors were relatively high, and more robust prototypes will be required for future field testing.
To determine the existing relationship between ethanol levels in biological fluids, such as blood and urine, and their correlation with causes of death in corpses admitted to the forensic medicine ...autopsy service in Honduras. The gas chromatography method was employed to determine the concentration of ethyl alcohol. After a statistical analysis using measures of central tendency, it was found that the urine sample presented a median of 227.30mg/dL, while in the blood, it was 276.86mg/dL. After some distribution tests and correlation, it was determined that higher alcohol concentrations influence the "ACCIDENTAL" cause of death, with values of median alcohol concentration of 228.56mg/dL in blood and 277.44 mg/dL in urine. Still, the most frequent cause of death was "HOMICIDE", which differs in the age of the subjects and their ethanol concentration, with values of median alcohol concentration of 227.20mg/dL in blood and 276.86mg/dL in urine; similarities of median indicates that both samples are related or share a standard feature. Subsequent statistical tests showed that blood concentration values are more representative than urine values since the latter represents the final metabolic stage of alcohol in the body and exhibits more excellent dispersion. The average age of the individuals analyzed was 33 years old. However, it should be noted that individuals involved in "ACCIDENTAL" causes of death were in the lower age range corresponding to the so-called young adults.
Keywords: Forensic sciences; blood alcohol concentration; autopsy; alcohol in urine
Background
Wrist‐worn transdermal alcohol sensors have the potential to change how alcohol consumption is measured. However, hardware and data analytic challenges associated with transdermal sensor ...data have kept these devices from widespread use. Given recent technological and analytic advances, this study provides an updated account of the performance of a new‐generation wrist‐worn transdermal sensor in both laboratory and field settings.
Methods
This work leverages machine learning models to convert transdermal alcohol concentration data into estimates of Breath Alcohol Concentration (BrAC) in a large‐scale laboratory sample (N = 256, study 1) and a pilot field sample (N = 27, study 2). Specifically, in both studies, the accuracy of the translation is evaluated by comparing BAC estimates yielded by BACtrack Skyn to real‐time breathalyzer measurements collected in the laboratory and in the field.
Results
The newest version of the Skyn device demonstrates a substantially lower error rate than older hand‐assembled prototypes (0% to 7% vs. 29% to 53%, respectively). On average, real‐time estimates of BrAC yielded by these transdermal sensors are within 0.007 of true BAC readings in the laboratory context and within 0.019 of true BrAC readings in the field. In both contexts, the distance between true and estimated BrAC was larger when only alcohol episodes were examined (laboratory = 0.017; field = 0.041). Finally, results of power‐law‐curve projections indicate that, given their accuracy, transdermal BrAC estimates in real‐world contexts have the potential to improve markedly (>25%) with adequately sized datasets for model training.
Conclusion
Findings from this study indicate that the latest version of the transdermal wrist sensor holds promise for the accurate assessment of alcohol consumption in field contexts. A great deal of additional work is needed to provide a full picture of the utility of these devices, including research with large participant samples in field contexts.
This study provides an updated account of the performance of a new generation transdermal alcohol biosensor. On average, sensor derived real‐time estimates of BAC (blood alcohol content) are within 0.007 of true BAC readings in laboratory contexts and within 0.019 of BAC in field contexts. Furthermore, models suggest real‐world transdermal sensor accuracy is likely to improve (>25%) given larger datasets for model training. Findings indicate alcohol biosensors hold promise for the assessment of alcohol consumption in real‐world settings.
•We examined a new-generation, smartphone-integrated alcohol biosensor in the lab.•Machine learning was used to convert biosensor data into estimates of BAC.•The new sensor demonstrated strong ...capabilities for detecting episodes of drinking.•BAC estimates for the new sensor were more accurate than those from an older device.
Transdermal biosensors offer a noninvasive, low-cost technology for the assessment of alcohol consumption with broad potential applications in addiction science. Older-generation transdermal devices feature bulky designs and sparse sampling intervals, limiting potential applications for transdermal technology. Recently a new-generation of transdermal device has become available, featuring smartphone connectivity, compact designs, and rapid sampling. Here we present initial laboratory research examining the validity of a new-generation transdermal sensor prototype.
Participants were young drinkers administered alcohol (target BAC = .08 %) or no-alcohol in the laboratory. Participants wore transdermal sensors while providing repeated breathalyzer (BrAC) readings. We assessed the association between BrAC (measured BrAC for a specific time point) and eBrAC (BrAC estimated based only on transdermal readings collected in the immediately preceding time interval). Extra-Trees machine learning algorithms, incorporating transdermal time series features as predictors, were used to create eBrAC.
Failure rates for the new-generation prototype sensor were high (16 %–34 %). Among participants with useable new-generation sensor data, models demonstrated strong capabilities for separating drinking from non-drinking episodes, and significant (moderate) ability to differentiate BrAC levels within intoxicated participants. Differences between eBrAC and BrAC were 60 % higher for models based on data from old-generation vs new-generation devices. Model comparisons indicated that both time series analysis and machine learning contributed significantly to final model accuracy.
Results provide favorable preliminary evidence for the accuracy of real-time BAC estimates from a new-generation sensor. Future research featuring variable alcohol doses and real-world contexts will be required to further validate these devices.
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