Using strain to uncover the interplay between two- and three-dimensional charge density waves in high-temperature superconducting YBa2Cu3Oy.

Uniaxial pressure provides an efficient approach to control charge density waves in YBa2Cu3Oy. It can enhance the correlation volume of ubiquitous short-range two-dimensional charge-density-wave correlations, and induces a long-range three-dimensional charge density wave, otherwise only accessible at large magnetic fields. Here, we use x-ray diffraction to study the strain dependence of these charge density waves and uncover direct evidence for a form of competition between them. We show that this interplay is qualitatively described by including strain effects in a nonlinear sigma model of competing superconducting and charge-density-wave orders. Our analysis suggests that strain stabilizes the 3D charge density wave in the regions between disorder-pinned domains of 2D charge density waves, and that the two orders compete at the boundaries of these domains. No signatures of discommensurations nor of pair density waves are observed. From a broader perspective, our results underscore the potential of strain tuning as a powerful tool for probing competing orders in quantum materials.

A diflunisal related fatality: a case report.

A case is reported where the death of an individual resulted from the ingestion of diflunisal. Diflunisal was identified by a combination of liquid chromatography, UV spectrophotometry and colorimetry. Diflunisal was quantified in blood (260 mg/l), bile (71 mg/l), kidney (350 mg/kg), liver (400 mg/kg), stomach contents (34 mg) and urine (78 mg/l). No previous literature references discussing diflunisal related fatalities were available.

A fentanyl fatality involving midazolam.

A case is presented of a 35-year-old black African male anesthesiology resident, found dead in his apartment. At the scene a syringe, butterfly intravenous line and a bottle of Versed (Midazolam) were recovered. A comprehensive screen for common drugs of abuse and therapeutic agents failed to detect any drugs in blood and urine. The blood ethanol concentration was 0.06 g/dl. A GC/MS SIM assay for midazolam was developed. A sub-therapeutic midazolam blood concentration of 7.5 ng/ml was detected and concentrations (ng/ml or ng/g) in bile, urine, and liver were 3.3, 7.5, and 96, respectively. The syringe fluid was then analyzed and found to contain only fentanyl, midazolam was absent. The blood fentanyl concentration was 4.9 ng/ml which is consistent with those reported in fentanyl fatalities. Fentanyl concentrations (ng/ml or ng/g) in bile, urine, and liver were 8.8, 5.0, and 5.9, respectively. The cause of death was ruled to be fentanyl intoxication and the manner of death undetermined.

Chloral hydrate overdose: trichloroethanol detection by gas chromatography/mass spectrometry.

A case is presented where an individual ingested a fatal dose of chloral hydrate. Trichloroethanol (TCE), the metabolite of chloral hydrate, was initially identified by the Fujiwara reaction and quantified by gas chromatography/mass spectrometry in blood )127 mg/l), urine (128 mg/l) and stomach contents (25 mg total).

Bupropion and alcohol fatal intoxication: case report.

A fatality due to the ingestion of bupropion and ethanol is presented. Bupropion and its metabolites were extracted from several tissues and identified using gas chromatography with nitrogenphosphorus and mass spectrometry detection. The concentrations of bupropion, hydroxybupropion and the erythroamino and threoamino alcohol metabolites in heart blood were 4.2, 5.0, 0.6 and 4.6 mg/l, respectively. The heart blood ethanol concentration was 0.27 g/dl. In addition, bupropion was distributed as follows: subclavian blood, 6.2 mg/l; bile, 1.4 mg/l; kidney, 2.4 mg/l; liver, 1.0 mg/kg; stomach contents, 16 mg and urine, 37 mg/l.

Fluoxetine and violent death in Maryland.

A retrospective Medical Examiner case review of all deaths in Maryland where either fluoxetine or tricyclic antidepressant (TCA) use was forensically detected was conducted for the time period January 1987-July 1991. Case records and toxicology reports from the Office of the Chief Medical Examiner were reviewed to determine cause and manner of death, circumstances of death, demographic information on the decedent, prior medical history of the decedent, and presence and level of either fluoxetine or TCA in various body fluids/tissues. Suicide was the manner of death most frequently associated with TCA and fluoxetine detection. Violent methods were more often associated with fluoxetine suicides than with TCA suicides (65% v. 23%, P < 0.001). Demographic characteristics of antidepressant-related deaths in Maryland were similar to those of the entire USA. Possible explanations for the results obtained include the inherent lower lethality of fluoxetine compared to the TCAs, necessitating the use of additional means to complete the act of suicide; that physicians may have switched more impulsive, high risk patients to this new agent as it became available, thus creating a selection bias for more violence-prone individuals in the fluoxetine group; or that fluoxetine may be associated with induction of violence and/or suicidal ideation. Further research examining the possible association of these agents with violent acts is warranted.

Cocaine fatality: an unexplained blood concentration in a fatal overdose.

A case is presented of a 26-year-old female who died as a result of cocaine intoxication. A blood cocaine concentration of 330 mg/l, about 1.5 times greater than the highest concentration previously reported, was found. Blood benzoylecgonine and ecgonine methyl ester concentrations were 50 and 18 mg/l, respectively. The unusually high blood concentrations of cocaine and the metabolites are suggestive of a massive administration, however, the history suggests a series of recreational uses. The manner of death was undetermined.

Determination of fentanyl in whole blood at subnanogram concentrations by dual capillary column gas chromatography with nitrogen sensitive detectors and gas chromatography/mass spectrometry.

Two methods for the determination of fentanyl at subnanogram concentrations in whole blood have been developed and evaluated. The initial screening was by gas chromatography with nitrogen sensitive detection (GC/NPD) in a splitless injection onto two fused-silica, 0.32-mm i.d. capillary columns (5% and 50% phenyl methyl silicone). Confirmation was by gas chromatography/mass spectrometry (GC/MS) using selected ion monitoring of a splitless injection onto a 0.1-mm i.d., 0.34-microns 5% phenyl methyl silicone capillary column. The methods were studied at fentanyl concentrations over the range 0.05 to 5.0 ng/mL using 2 mL of blood. The detection limits were set at 0.10 ng/mL for GC/NPD and 0.05 ng/mL for GC/MS. The overall recovery of fentanyl was found to be greater than 75% over the range of 0.25 to 2.5 ng/mL. The within-run precision determined at fentanyl concentrations of 0.25 and 1.0 ng/mL showed coefficients of variation ranging from 8.7 to 14.8%. The between-run precision determined at concentrations of 0.4 and 0.8 ng/mL showed coefficients of variation ranging from 3.3 to 11.6%. The blood calibration curves in the range of 0.25 to 2.5 ng/mL monitored over a 3-month period showed a mean correlation coefficient of 0.99 for both the GC/NPD and GC/MS methods.

Application of the Abbott TDx lidocaine, phenytoin, and phenobarbital assays to postmortem blood specimens.

The TDx fluorescence polarization immunoassays (FPIA) for some therapeutically monitored drugs (lidocaine, phenytoin, phenobarbital) were applied to the analysis of postmortem blood specimens. After an initial calibration using the appropriate TDx calibrators, blood bank blood fortified with known amounts of drug was analyzed by FPIA. Postmortem blood specimens containing the drugs, postmortem specimens not containing the drugs of interest (negatives), and randomly selected postmortem blood specimens fortified with known amounts of the drugs were analyzed by the FPIA and reference gas chromatographic (GC) methods. Concentrations determined in blood bank and postmortem blood specimens showed excellent correlation between the two methods and produced lines with slopes ranging from 0.98 to 1.08. In each case the correlation coefficient was greater than 0.97. Analysis of all negative specimens produced FPIA values below the limit of quantitation of the reference GC assay.

The analysis of ethanol in serum, blood, and urine: a comparison of the TDx REA ethanol assay with gas chromatography.

Studies were performed to evaluate two Abbott TDx ethanol assays, one which is commercially available (TDx-INT) and the other which is under experimental trial (TDx-MTT). Both assays employ radiative energy attenuation (REA) and differ only in the dye used for the chromogen. TDx-INT and TDx-MTT were compared to a headspace gas chromatographic method of analysis. Four types of specimens were studied: serum, urine, postmortem blood, and blood from intoxicated drivers (DWI). Specimens not containing ethanol were also analyzed. Statistical evaluation by least square regression analysis revealed good correlation (greater than 0.98) for each group when ethanol values obtained by either TDx method were compared to the value obtained by gas chromatography. The slopes of the lines ranged from 0.96 to 1.02.

Liquid chromatographic determination of salicylate and methyl salicylate in blood and application to a postmortem case.

A liquid chromatographic method is presented for the quantitation of salicylate and methyl salicylate in blood. It employs an initial alkaline extraction to separate methyl salicylate from salicylate. Methyl salicylate is then hydrolyzed to salicylate, extracted under acidic conditions and chromatographed. This method was used in an attempt to identify methyl salicylate and salicylate in a postmortem case.

Evaluation of the Coat-A-Count 125I fentanyl RIA: comparison of 125I RIA and GC/MS-SIM for quantification of fentanyl in case urine specimens.

The Coat-A-Count solid phase 125I Fentanyl Radioimmunoassay was evaluated with respect to linearity and precision using equine urine fortified with fentanyl and then compared with a gas chromatographic/mass spectrometric method for quantification of fentanyl in urine. The RIA assay was found to be linear over the urine fentanyl concentration range of 0.25 to 7.5 ng/mL and precise with coefficients of variation (CV) ranging from 9.6 to 19.3%. The RIA calibrators, ranging in fentanyl concentrations from 0.25 to 7.5 ng/mL, and controls, at mean fentanyl concentrations of 0.46 and 1.32 ng/mL, were compared by both the RIA and GC/MS methods. The cross-reactivity with the 125I RIA test was determined for the fentanyl metabolites, norfentanyl and hydroxyfentanyl, and found to be 5% and 35%, respectively. The illicit fentanyl analogs were found to show significant cross-reactivity, ranging from 20 to 100%. The 125I RIA was compared to GC/MS quantifications of fentanyl in 35 positive and 20 negative case urine specimens.

Vitreous humor in the evaluation of postmortem blood ethanol concentrations.

Many studies have been published comparing blood (B) ethanol (EtOH) and vitreous humor (VH) EtOH concentrations. We conducted a similar study of routinely collected specimens to determine (1) whether the reported average VH/B ratios are consistent, (2) the percentage of cases with VH/B ratios outside of the expected range, and (3) the magnitude of B EtOH that can be associated with negative VH EtOH (less than 0.01 g/dL). VH EtOH less than 0.01 g/dL was associated with 41 specimens; 34 specimens had B EtOH less than 0.03 g/dL while a B EtOH as high as 0.12 g/dL was measured. For B EtOH less than 0.10 g/dL, 67% had VH EtOH within 0.02 g/dL of B EtOH (N = 101). For B EtOH greater than or equal to 0.10 g/dL, the VH/B EtOH ratio ranged from 0.10 to 1.91; the mean ratio was 1.17 and the median ratio was 1.18 (N = 205); and 64% had a ratio between 1.00 and 1.39. Vitreous humor can be used to facilitate understanding the significance of postmortem blood EtOH concentrations.

Alternative specimens for workplace drug testing.

Recent advances in analytical techniques have enabled the detection of drugs and drug metabolites in alternative biological specimens for the purposes of workplace testing. A wide variety of specimens are available, each providing valuable information concerning prior or current drug use. The present focus is on oral fluid (saliva), hair, and sweat. An extensive evaluation by the Division of Workplace Programs of the Department of Health and Human Services is underway to determine the utility of these specimens in federally regulated programs. In future years, the testing of alternative specimens will expand our ability to understand the patterns of drug use and will become routine in all areas of forensic toxicology.

Abbott phencyclidine and barbiturates abused drug assays: evaluation and comparison of ADx FPIA, TDx FPIA, EMIT, and GC/MS methods.

This study evaluated the capability of the Abbott ADx assays to test for phencyclidine (PCP) and barbiturates in urine specimens by comparison to TDx, EMIT, and gas chromatographic/mass spectrometric (GC/MS) methods. Within-run and between-run precision were determined using three control samples (35, 100, and 250 ng/mL PCP; 0.4, 0.6, and 1.0 mg/L secobarbital) tested over a two-week period. Controls were analyzed in both single assay (batch) and multiple assay (combination) modes. Within-run coefficients of variation (CVs) for the three PCP controls were 2.4, 2.6, and 2.2%, respectively; the between-run CVs were 4.0, 3.5, and 2.8%, respectively. The within-run CVs for the three barbiturate controls were 3.0, 2.7, and 2.7%, respectively; the between-run CVs were 5.6, 4.7, and 4.5%, respectively. Fifty specimens not containing PCP or barbiturates, 50 specimens containing PCP, and 50 specimens containing barbiturates were tested by ADx, TDx, EMIT, and GC/MS. The methods compared favorably and no false positive or false negative results were obtained by any immunoassay method for any assay when compared to GC/MS.

A method for the determination of 11-nor-delta-9-tetrahydrocannabinol-9-carboxylic acid in urine using high performance liquid chromatography with electrochemical detection.

11-Nor-delta-9-tetrahydrocannabinol-9-carboxylic acid (THC-COOH) was isolated using solid phase extraction and identified with high performance liquid chromatography (HPLC) with electrochemical detection (EC). HPLC/EC was compared to an established HPLC procedure using ultraviolet (UV) detection. Statistical analysis revealed good precision, linearity, and correlation between the HPLC/EC and HPLC/UV methods. Within-run and between-run precision for the HPLC/EC vs. HPLC/UV analyses yielded coefficients of variation of 4.1 vs. 6.7% and 8.3 vs. 10.9%, respectively. Standard curves over a range of 20 to 160 ng/mL of THC-COOH in fortified urine on four separate analytical runs yielded correlation coefficients of greater than 0.99 for each method. Quantitative results from 15 positive urine specimens also compared favorably between the two methods (r = 0.9923). Using an immunoassay screening technique with confirmation by HPLC/UV and high efficiency thin layer chromatography (HETLC), further evaluation of the HPLC/EC method was achieved by examining 50 cannabinoid positive and 50 cannabinoid negative clinical urine specimens and 500 sequentially collected postmortem urine specimens.

delta-9-Tetrahydrocannabinol analysis in forensic blood specimens using capillary column gas chromatography with nitrogen sensitive detection.

A method for the determination of delta-9-tetrahydrocannabinol (THC) in whole blood that employs hexane extraction followed by identification using gas chromatography with nitrogen/phosphorus detection has been developed. The assay is sensitive to 2 ng THC per mL blood and linear to concentrations up to 120 ng/mL (r = 0.998). Precision is demonstrated by coefficients of variation ranging from 3.6 to 9.1% (within run) and 7.1 to 8.0% (between run).

Carbon monoxide analysis: a comparison of two co-oximeters and headspace gas chromatography.

Three methods (IL-182 Co-Oximeter, IL-282 Co-Oximeter, and headspace gas chromatography) for the analysis of carbon monoxide in postmortem blood were studied and compared using a prepared reference standard, Quantra control materials, and 62 postmortem blood specimens. The methods compared favorably with one another. The linear regression equations for the 62 postmortem blood samples (range = 1.0 to 86% saturation) were: IL-282 vs. IL-182, y = 1.11x - 3.10, r = 0.981; IL-182 vs. GC, y = 0.88x + 2.97, r = 0.973; IL-282 vs. GC, y = 1.00x - 1.24, r = 0.986.

Fatality resulting from methylphenidate overdose.

A case involving an accidental overdose fatality resulting from an intravenous injection of crushed Ritalin (methylphenidate) tablets is presented. The drug was quantified by gas chromatography/nitrogen-phosphorus detection and confirmed by gas chromatography/mass spectrometry. Concentrations of drug were as follows: blood, 2.8 mg/L; bile, 5.7 mg/L; kidney, 3.0 mg/kg; liver, 2.1 mg/kg; and stomach contents, 1.6 mg total. Other drugs and volatile substances were not detected.

Flecainide intoxication.

A fatal case attributed to flecainide intoxication is presented. Quantitation was by capillary gas chromatography with nitrogen-phosphorus detection. The flecainide concentration in the blood was 13 mg/L as compared to a therapeutic range in serum of 0.2-1.0 mg/L. Flecainide concentrations in other specimens were as follows: bile, 160 mg/L; urine, 54 mg/L; vitreous humor, 7.4 mg/L; liver, 180 mg/kg; kidney, 74 mg/kg; and stomach contents, 120 mg.