Evaluation of breath alcohol instruments I. In vitro experiments with Alcolmeter Pocket Model

An Alcolmeter Pocket Model breath alcohol device, based on an electrochemical (fuel cell) oxidation principle for ethanol analysis, has been evaluated under in vitro conditions. The result of a test is displayed on an analogue meter within 20 – 30 seconds after sampling; replicate tests may be made within 3 – 5 minutes. The electrochemical detector used was found to respond to acetaldehyde, methanol, isopropanol and n-propanol vapours besides ethanol, but it was insensitive to acetone vapour. The Alcolmeter response with a 0 – 2.0 mg/ml scale was linearly related to ethanol vapour concentration up to 1.0 mg/ml blood alcohol equivalent concentration; above this level the response was curvilinear, the Alcolmeter reading being too low. The standard deviation of an ethanol vapour determination in vitro was ±0.0175 mg/ml at a mean concentration of 0.902 mg/ml. The accuracy of the device expressed as percent recovery at 0.50, 1.0 and 1.4 mg/ml blood alcohol concentrations was 96.8%, 98.3%, and 88.3%, respectively. When the Alcolmeter was calibrated at 0.50 mg/ml and used occasionally each day over an 18-day period, the drop in initial calibration was 0.01 mg/ml per week.     

Evaluation of breath-alcohol instruments. IV. Roadside tests with Alcolmeter pocket model

This paper reports results from a field trial with a breath-alcohol screening device--Alcolmeter pocket model. Breath tests were made with drivers apprehended during routine controls (road-blocks), for traffic violations and those involved in traffic accidents. Of 908 roadside breath tests made with chemical reagent tubes, 343 showed zero alcohol (no colour change) and these results were confirmed by Alcolmeter. Alcohol was detected in 191 tests but the level was judged as being below the legal limit of 0.50 mg/ml. The Alcolmeter results, however, ranged from 0 to 1.22 mg/ml (mean 0.21 mg/ml) and 15 individuals (7.8%) were above the legal limit. There were 373 positive chemical tube breath screening tests whereas in 5 cases (1.3%) Alcolmeter indicated a blood-alcohol level below 0.50 mg/ml. Duplicate determinations with the Alcolmeter device were highly correlated r = 0.93 +/- 0.02 (+/- S.E.), P less than 0.001. The standard deviation of a single breath-alcohol analysis under field conditions was +/- 0.10 mg/ml which corresponds to a coefficient of variation of 10%. The time interval between positive roadside breath test and blood-sampling ranged from 5 to 220 min (median 62 min). The results were therefore adjusted by 0.15 mg/ml per hour to compensate for ethanol metabolised between the time of sampling blood and breath. The corrected blood and breath values were well correlated r = 0.84 +/- 0.03, P less than 0.001 but the predictive power of the regression relationship was poor. The regression equation was y = 0.27 +/- 0.65x and the standard error estimate was +/- 0.21 mg/ml at the mean concentration of ethanol of 1.0 mg/ml.     

Evaluation of breath-alcohol instruments. III. Controlled field trial with Alcolmeter pocket model

A breath-alcohol screening device, Alcolmeter pocket model, was evaluated in a controlled field trial with policeman operating the instruments. The results of tests made with subjects before they drank alcohol were always zero. The standard deviation (S.D.) of breath alcohol determinations increased with increase in the concentration of alcohol in the sample, being 0.036 mg/ml at a mean blood-ethanol concentration of 0.53 mg/ml. The S.D. varied among subjects tested (from 0.022 to 0.053 mg/ml) as well as among the instruments used (from 0.023 to 0.054 mg/ml). The breath test results were on average less than the actual blood-ethanol concentrations when a 2100: 1 blood/breath ratio was used to calibrate the Alcolmeter device. Blood ethanol (x) and Alcolmeter readings (y) were highly correlated (r = 0.95 +/- 0.018) and the regression equation was y = -0.017 + 0.95x. At a mean blood-ethanol concentration of 0.50 mg/ml, the Alcolmeter instrument will indicate 0.46 mg/ml on average. The standard error estimate was 0.085 mg/ml, being 17% of the mean Alcolmeter reading and this corresponds to 95% confidence limits of +/- 0.17 mg/ml. The results of this study show that Alcolmeter pocket-model is a useful device for breath-alcohol screening purposes at a blood-alcohol level of 0.50 mg/ml. A blood/breath ratio of 2300 should be used to calibrate the Alcolmeter device.     

Minimum lung function for breath alcohol testing using the Lion Alcolmeter SD-400.

The aim of this study was to determine the minimum lung function required by an individual to complete a breath alcohol test successfully using a Lion Alcolmeter SD-400. A total of 331 subjects routinely referred to a busy clinical respiratory function laboratory for assessment of their lung function were tested. A total of 52 (15.7%) of these subjects were unable to provide an adequate sample after two attempts. The majority of the group (86.5%) were female. There was considerable overlap of the minimum lung function parameters between those subjects who were unsuccessful at all attempts and those who were successful. The failure rate of the subjects using the Lion Alcolmeter SD-400 was approximately 50% of that found in a previous study of the Lion SD-2.     

The effect of breath freshener strips on two types of breath alcohol testing instruments

The potential for breath freshener strips to interfere with the accuracy of a breath alcohol test was studied. Twelve varieties of breath freshener strips from five manufacturers were examined. Breath tests were conducted using the infrared based BAC DataMaster or the fuel cell based Alco-Sensor IV-XL, 30 and 150 seconds after placing a breath strip on the tongue. No effect was observed using the Alco-Sensor system. Some of the strips gave a small reading at 30 seconds (less than or equal to 0.010 g/210 L apparent alcohol) using the DataMaster. Readings on the DataMaster returned to zero by the 150 second test. A proper pre-test observation and deprivation period should prevent any interference from breath freshener strips on breath alcohol testing.     

Evaluation of the Dr?ger Alcotest model 7110 infrared breath alcohol analysing instrument

Until 1986, commercially-available infrared breath alcohol analysing instruments employed wavelengths in the region of 3.4 mu. The move to the 9.5 mu region in the Dr?ger Alcotest 7110 promised greater discrimination against endogenous compounds such as acetone. The present study confirmed that acetone interference is insignificant and that in terms of in vitro accuracy and precision, the ten 7110 units tested were superior to the Breathalyzer 900, the instruments they will replace for evidential testing in South Australia. The new unit meets the South Australian Police demand for portability and its shielding prevents interference fron any of the common radio frequency transmissions in Adelaide when operating as near to the source as possible. Comparisons of breath results (monthly averages) and their corresponding blood results accumulated during the first few months of operation showed no bias between the two techniques.     

The elimination rate of mouth alcohol: mathematical modeling and implications in breath alcohol analysis.

Mouth alcohol, if present in high enough concentrations, can falsely bias the accurate measurement of end-expiratory breath alcohol. Mouth alcohol will be eliminated over time, however, and can be modeled with a single term decaying exponential of the form: B0e-kt + C. It is important, however, to determine the model and its parameters when alcohol is already present within the biologic system. Using three individuals as their own controls, mouth alcohol was administered both before and after alcohol consumption followed by breath alcohol analysis performed at approximately 0.5 min intervals. The results showed that both model parameters (B0 and k) are effected and that the asymptotic value (C) is reached much sooner when alcohol already exists in the end-expiratory breath. Considering only three individuals were involved, the forensic-science importance appears to be that, as the end-expiratory breath alcohol concentration increases, the time necessary for the mouth alcohol to decrease to unbiased levels is decreased. Fifteen min of observation time prior to breath alcohol analysis appears to be more than adequate at forensically relevant concentrations.     

Comparing roadside with subsequent breath alcohol analyses and their relevance to the issue of retrograde extrapolation.

Driving while intoxicated (DWI) legislation requires proving the critical breath alcohol concentration (BrAC) at the time of driving. With time delayed analysis, retrograde extrapolation is occasionally employed but has several uncertainties associated with it. The present study attempts to address whether subjects actually arrested for DWI are likely to have BrAC values near the time of driving differing largely from those performed at a subsequent time. Selected officers arrested n = 161 subjects where roadside BrAC was determined with Pre-Arrest Breath Test (PBT) devices along with subsequent duplicate evidential analyses followed by an additional PBT analysis. These two sets of duplicates, one with large time interval (mean = 63.5 min.) and one with a 2-3 min difference, were then compared by several statistical methods. The results showing duplicate variability did not differ when the long time interval existed (F = 1.0, P > 0.05). A small but significant decrease in BrAC with respect to time appeared for the duplicate PBT data. Retrograde extrapolation applied to the data employing an assumed 0.015 g/210 l/h yielded a small but significant overestimate of the actual roadside PBT result. Finally, evidentiary analyses performed within 2 h of driving will provide good estimates and certainly not overestimates, of the BrAC existing at the time of driving and it appears that extrapolation may be unwarranted in these cases.     

Level of lung function required to use the Camic Datamaster breath alcohol testing device.

In the UK a person who, without reasonable excuse, fails to provide a breath specimen when required to under the 1988 Road Traffic Act, is guilty of an offense. In the past many suspects claim to have experienced difficulty providing breath samples for evidential machines. This paper describes experiments carried out on human subjects, both healthy and suffering a variety of respiratory illness. The experiments were designed to assess the level of respiratory performance required to provide a satisfactory breath sample for the Camic Datamaster. In this study it was found that both actual spirometry values and the percentage of predicted values were both important indicators.     

Analysis of breath alcohol with a multisensor array: instrumental setup, characterization and evaluation

The purpose of this work was to evaluate if it was possible to measure the alcohol concentration in breath by a multisensor array, i.e. an electronic nose. The most important aspects were to clarify technical advantages and disadvantages and if the technique is at all suitable for forensic breath alcohol analysis. Even though the system set-up was far from optimal it is clear that it was possible to quantify breath alcohol with a best-case root mean square error = 16.8 mol ppm ethanol (= 0.037 mg/l). However, the method needs significant development especially of the sensor devices. The sensor array was composed of ten metal oxide silicon field effect transistors (MOSFET) with various catalytic gates and one infrared-based CO2 sensor. The system was evaluated by monitoring the breath ethanol concentration of five test persons after intake of alcohol. Gas chromatography was used in parallel to measure the actual breath alcohol concentration. Different data evaluation techniques applied were projection to latent structure (PLS) and artificial neural networks (ANN).     

甲基苯丙胺染毒动物模型的建立与评价

苯丙胺类中枢兴奋剂是21世纪最广泛滥用的毒品.甲基苯丙胺(methamphetamine,MA)的中毒机理、精神依赖性、耐药性以及治疗药物的研发是当前研究的热点.MA中毒动物模型的建立是研究MA相关问题的基础.MA动物模型建立的规范化和标准化对以后MA的进一步研究奠定了实验基础.本文结合国内外关于MA中毒动物的文献资料,通过对MA急性、亚急性以及慢性中毒动物模型研究的论述.对造模原理、造模方法 和评价标准进行了探讨,并指出建立以动物为主体的MA中毒模型来进行相关实验研究的必要性以及重要性.     

Police hiring and retention of sexual minorities in Georgia and Texas after Lawrence v. Texas

In this telephone interview study, hiring and retention policies and practices relevant to sexual minority officers among twenty selected police departments in Georgia and Texas were examined. The authors examined policies and practices in place before and after the U.S. Supreme Court's 2003 decision in Lawrence v. Texas, in which the Court struck down Texas' sodomy law on grounds that it violated due process and the right to privacy, in effect decriminalizing homosexual conduct throughout the nation. Conclusions and policy implications for law enforcement hiring practices in light of this landmark decision are discussed.     

The feasibility of external blind DNA proficiency testing. II. Experience with actual blind tests

The background and goals of a national study to determine the feasibility of blind proficiency testing in U.S. forensic DNA laboratories are discussed. Part of the project involved designing and executing a series of fifteen blind proficiency tests. Execution included biological specimen donor recruitment and case evidence manufacturing. Simulated cases were submitted to DNA laboratories by law enforcement agencies and in some cases by other forensic-science laboratories. Replicate-manufactured evidence was submitted to reference laboratories to simulate the workings of a larger-scale program. Ten tests were straightforward, and essentially tested analytical ability. Five tests involved selecting on the basis of case facts appropriate bloodstains for typing from a bloodstain pattern. We describe in detail our experience in designing and conducting these blind proficiency test trials, and relate those experiences to the overall issue of blind proficiency testing as a quality-assurance tool in forensic DNA laboratories. In this feasibility test series, one blind test was detected by a laboratory, a second one was shown to the lab by law enforcement, and a third was never completed because of lapses in communication. Turnaround times were relatively fast in the independent/commercial labs and relatively slow in the larger public laboratories. Two cross-state case-to-case CODIS "hits" were "planted" among the first series of ten blind tests. One pair was detected. One member of the second pair went to a lab that was not CODIS-ready.     

Determination of potassium/sodium ratio in heart tissue. Evaluation of its use as an index of myocardial ischaemic damage. Comparison with the nitro-BT test

The succinate dehydrogenase method of staining and the determination of the K⁺/Na⁺ ratio of heart tissue have been applied to forensic material as a tool for demonstrating early signs of myocardial infarctions. Both methods are controlled by a series of forensic cases dying from causes other than arteriosclerosis of the coronary arteries. Based on an analysis of normal material some factors influencing the K⁺/Na⁺ ratio are defined. It is concluded that the determination of the K⁺/Na⁺ ratio shows more infarcts than the formazan method; however, the evaluation of the K⁺/Na⁺ ratio is difficult. The K⁺/Na⁺ determination is not recommended for routine use. A possible indication for the use of the K⁺/Na⁺ determination together with the formazan test could be cases of instantaneous death by accidents suspected to have been provoked by a fatal heart attack.     

一起因胆囊手术引起的医疗纠纷鉴定案介评

本文通过对一起医疗纠纷鉴定的评价 ,更要求法医鉴定人有扎实的医学功底 ;应大力宣传法医尸体解剖在查明死因上的重要性 ,一旦发生医疗纠纷 ,主管部门应及时查封病历等有关材料 ,杜绝涂改、伪造等不法行为。建议有关部门对医疗纠纷鉴定工作立法。     

一起因胆囊手术引起的医疗纠纷鉴定案介评

本文通过对一起纠纷鉴定的评价，更要求法医鉴定人有扎实的医学功底；应大力宣传法医尸体解剖在查明死因上的重要性，一旦发生医疗纠纷，主管部门应及时查封病历等有关材料，杜绝涂改、伪造等不法行为。建议有关部门对医疗纠纷鉴定工作立法。