Carbon footprint of South Dakota dairy production system and assessment of mitigation options.

Livestock production contributes to greenhouse gas (GHG) emissions. However, there is a considerable variability in the carbon footprint associated with livestock production. Site specific estimates of GHG emissions are needed to accurately focus GHG emission reduction efforts. A holistic approach must be taken to assess the environmental impact of livestock production using appropriate geographical scale. The objective of this study was to determine baseline GHG emissions from dairy production in South Dakota using a life cycle assessment (LCA) approach. A cradle-to-farm gate LCA was used to estimate the GHG emissions to produce 1 kg of fat and protein corrected milk (FPCM) in South Dakota. The system boundary was divided into feed production, farm management, enteric methane, and manure management as these activities are the main contributors to the overall GHG emissions. The production of 1 kg FPCM in South Dakota dairies was estimated to emit 1.23 kg CO2 equivalents. The major contributors were enteric methane (46%) and manure management (32.7%). Feed production and farm management made up 14.1 and 7.2%, respectively. The estimate is similar to the national average but slightly higher than the California dairy system. The source of corn used in the dairies influences the footprint. For example, South Dakota corn had fewer GHG emissions than grain produced and transported in from Iowa. Therefore, locally and more sustainably sourced feed input will contribute to further reducing the environmental impacts. Improvements in efficiency of milk production through better genetics, nutrition animal welfare and feed production are expected to further reduce the carbon footprint of South Dakota dairies. Furthermore, anaerobic digesters will reduce emissions from manure sources.

CO2 and N2 O emissions and microbial community structure from fields that include salt-affected soils.

Although salinity and sodicity are worldwide problems, information on greenhouse gas (GHG) emissions from agricultural salt-affected soils is scarce. The CO2 -C and N2 O-N emissions were quantified from three zones intertwined within a single U.S. northern Great Plains field: a highly productive zone (electrical conductivity with 1:1 soil/water mass ratio [EC1:1 ] = 0.4 dS m-1 ; sodium adsorption ratio [SAR] = 1.8), a transition zone (moderately salt-affected; EC1:1  = 1.6 dS m-1 ; SAR = 4.99), and a saline/sodic zone (EC1:1  = 3.9 dS m-1 ; SAR = 22). In each zone, emissions were measured every 4 h for 7 d in four randomly placed chambers that were treated with two N rates (0 and 224 kg N ha-1 ). The experiment was conducted in 2018 and 2019 during similar seasonal periods. Soil samples taken from treatments after GHG measurement were analyzed for soil inorganic N, and microbial biomass from different communities was quantified using phospholipid fatty acid analysis. Real-time polymerase chain reaction was used to quantify the number of copies of some specific denitrification functional genes. The productive zone had the highest CO2 -C, the lowest N2 O-N emissions, and the greatest microbial biomass, whereas the saline/sodic zone had the lowest CO2 -C, the highest N2 O-N emissions, and the lowest microbial biomass. Within a zone, urea application did not influence CO2 -C emissions; however, N2 O-N emissions from the urea-treated saline/sodic zone were 84 and 57% higher than from the urea-treated productive zone in 2018 and 2019, respectively. The copy number of the nitrite reductase gene, nirS, was 42-fold higher in the saline/sodic zone than in the productive soil, suggesting that the saline/sodic soil had a high potential for denitrification. These findings suggest N2 O-N emissions could be reduced by not applying N to saline/sodic zones.

How different soil moisture levels affect the microbial activity / Como diferentes níveis de umidade do solo afetam a atividade microbiana de um solo de terras baixas usado para cultivo do arroz?

ABSTRACT: The lowland soils are characterized by high susceptibility to water saturation. This anaerobic condition is usually reported in paddy fields and alters the decomposition process of soil organic compounds. The aim of this study was to evaluate the soil microbial and enzymatic activity of a lowland soil at different soil moisture contents. A poorly drained Albaqualf cultivated with irrigated rice was used to evaluate microbial and enzymatic activity in treatments with different levels of soil moisture, being: i) 60% of field capacity (FC) (60%FC); ii) 100% of FC (100%FC); iii) flooded soil with a 2 cm water layer above soil surface, and iv) soil kept at 60%FC with late flood after 29 days the incubation. The greater soil microbial activity was observed in the 100%FC treatment, being 41% greater than 60%FC treatment and only 2% higher than flooded treatment. The enzymatic activity data by fluorescein diacetate (FDA) hydrolysis corroborated the higher CO2 release in treatments with higher soil moisture content. Differently from the results reported, the main methodologies to evaluate microbial activity still recommend maintenance of the soil with a moisture content close to 60% of the FC. However, in lowland soil with history of frequent paddy fields, the maintenance of moisture close to 60% of the FC can limit the microbial activity. The soil respiration technique can be used to evaluate the microbial activity in flooded soil conditions. However, further studies should be conducted to understand the effect of the cultivation history on the microbial community of these environments.

RESUMO: Os solos de várzea são caracterizados pela alta suscetibilidade à saturação por água. Esta condição anaeróbica é geralmente encontrada em solos arrozeiros e altera o processo de decomposição dos compostos orgânicos do solo. O objetivo deste estudo foi avaliar a atividade microbiana e enzimática de um solo de várzea sob diferentes teores de umidade no solo. Um Planossolo historicamente cultivado com arroz irrigado foi utilizado para avaliar a atividade microbiana e enzimática em tratamentos com diferentes níveis de umidade do solo, sendo: i) 60% de capacidade de campo (CC) (60%CC); ii) 100% da CC (100%CC); iii) solo inundado com uma camada de água de 2 cm acima da superfície do solo; e iv) solo mantido a 60%CC com inundação após 29 dias da incubação. A maior atividade microbiana do solo foi observada no tratamento 100%CC, sendo 41% maior que o tratamento 60%CC e 2% maior que tratamento inundado. Os dados da atividade enzimática pela hidrólise do diacetato de fluoresceína (FDA) corroboraram a maior liberação de CO2 nos tratamentos com maior umidade do solo. Diferentemente dos resultados encontrados, as principais metodologias para avaliação da atividade microbiana ainda recomendam manter o solo com umidade próxima a 60% da CC. No entanto, em solos de várzea com históricos de cultivos de arroz, a manutenção de umidade próxima a 60% da CC pode limitar a atividade microbiana. A técnica de respiração do solo pode ser usada para avaliar a atividade microbiana em condições de solo inundado. No entanto, mais estudos devem ser realizados para entender o efeito do histórico de cultivo na comunidade microbiana nesses ambientes.

Evaluating Affordable Cranial Ultrasonography in East African Neonatal Intensive Care Units.

Neuroimaging is a valuable diagnostic tool for the early detection of neonatal brain injury, but equipment and radiologic staff are expensive and unavailable to most hospitals in developing countries. We evaluated an affordable, portable ultrasound machine as a quantitative and qualitative diagnostic tool and to establish whether a novice sonographer could effectively operate the equipment and obtain clinically important information. Cranial ultrasonography was performed on term healthy, pre-term and term asphyxiated neonates in Rwandan and Kenyan hospitals. To evaluate the detection of ventriculomegaly and compression injuries, we measured the size of the lateral ventricles and corpus callosum. The images were also assessed for the presence of other cerebral abnormalities. Measurements were reliable across images, and cases of clinically relevant ventriculomegaly were detected. A novice sonographer had good-to-excellent agreement with an expert. This study demonstrates that affordable equipment and cranial ultrasound protocols can be used in low-resource settings to assess the newborn brain.

Modeling the impacts of temperature and precipitation changes on soil CO2 fluxes from a Switchgrass stand recently converted from cropland.

Switchgrass (Panicum virgatum L.) is a perennial C4 grass native to North America and successfully adapted to diverse environmental conditions. It offers the potential to reduce soil surface carbon dioxide (CO2) fluxes and mitigate climate change. However, information on how these CO2 fluxes respond to changing climate is still lacking. In this study, CO2 fluxes were monitored continuously from 2011 through 2014 using high frequency measurements from Switchgrass land seeded in 2008 on an experimental site that has been previously used for soybean (Glycine max L.) in South Dakota, USA. DAYCENT, a process-based model, was used to simulate CO2 fluxes. An improved methodology CPTE [Combining Parameter estimation (PEST) with "Trial and Error" method] was used to calibrate DAYCENT. The calibrated DAYCENT model was used for simulating future CO2 emissions based on different climate change scenarios. This study showed that: (i) the measured soil CO2 fluxes from Switchgrass land were higher for 2012 which was a drought year, and these fluxes when simulated using DAYCENT for long-term (2015-2070) provided a pattern of polynomial curve; (ii) the simulated CO2 fluxes provided different patterns with temperature and precipitation changes in a long-term, (iii) the future CO2 fluxes from Switchgrass land under different changing climate scenarios were not significantly different, therefore, it can be concluded that Switchgrass grown for longer durations could reduce changes in CO2 fluxes from soil as a result of temperature and precipitation changes to some extent.

Meta-Analysis of Soybean-based Biodiesel.

Biofuel policy changes in the United States have renewed interest in soybean [ (L.) Merr.] biodiesel. Past studies with varying methodologies and functional units can provide valuable information for future work. A meta-analysis of nine peer-reviewed soybean life cycle analysis (LCA) biodiesel studies was conducted on the northern Great Plains in the United States. Results of LCA studies were assimilated into a standardized system boundary and functional units for global warming (GWP), eutrophication (EP), and acidification (AP) potentials using biodiesel conversions from peer-reviewed and government documents. Factors not fully standardized included variations in NO accounting, mid- or end-point impacts, land use change, allocation, and statistical sampling pools. A state-by-state comparison of GWP lower and higher heating values (LHV, HHV) showed differences attributable to variations in spatial sampling and agricultural practices (e.g., tillage, irrigation). The mean GWP of LHV was 21.1 g·CO-eq MJ including outliers, and median EP LHV and AP LHV was 0.019 g·PO-eq MJ and 0.17 g·SO-eq MJ, respectively, using the limited data available. An LCA case study of South Dakota soybean-based biodiesel production resulted in GWP estimates (29 or 31 g·CO-eq MJ; 100% mono alkyl esters [first generation] biodiesel or 100% fatty acid methyl ester [second generation] biodiesel) similar to meta-analysis results (30.1 g·CO-eq MJ). Meta-analysis mean results, including outliers, resemble the California Low Carbon Fuel Standard for soybean biodiesel default value without land use change of 21.25 g·CO-eq MJ. Results were influenced by resource investment differences in water, fertilizer (e.g., type, application), and tillage. Future biofuel LCA studies should include these important factors to better define reasonable energy variations in regional agricultural management practices.

Assessment of the performance of small field of view gamma cameras for sentinel node imaging.

OBJECTIVE: To develop a method for the assessment of small field of view (SFOV) gamma cameras using a novel phantom designed to simulate the localization of sentinel nodes in the presence of a high-activity injection site. MATERIALS AND METHODS: The phantom consisted of a cube-shaped acrylic glass support frame. Sixteen acrylic glass plates and nine bars were stacked within the frame to allow a variable configuration of the simulated node depth and node-to-injection site separation. Syringes filled with Tc were used to simulate activity at the injection site and node. Scintigraphic imaging was carried out and the images were assessed subjectively and quantitatively through calculation of the contrast-to-noise ratio. The detection performance of an SFOV gamma camera was then compared with that of a large field of view gamma camera. RESULTS: The detectability studies showed that the SFOV gamma camera could detect low activity in nodes by visual examination of images and with contrast-to-noise ratios ranging from 3 to 62. In particular, the phantom showed the limits of node detection using an SFOV gamma camera over activity ratios less than 1 : 100 and at depths below 45 mm with 25 mm of node-to-injection site separation. Visual subjective assessment of images acquired under the same conditions showed that the SFOV gamma camera was superior to a large field of view camera for the detection of nodes at a node-to-injection site separation of 25 mm. CONCLUSION: A low-cost phantom has been designed and fabricated that provides a versatile method for the assessment of SFOV gamma cameras intended for sentinel node imaging.

Tillage and corn residue harvesting impact surface and subsurface carbon sequestration.

Corn stover harvesting is a common practice in the western U.S. Corn Belt. This 5-yr study used isotopic source tracking to quantify the influence of two tillage systems, two corn ( L.) surface residue removal rates, and two yield zones on soil organic C (SOC) gains and losses at three soil depths. Soil samples collected in 2008 and 2012 were used to determine C enrichment during SOC mineralization, the amount of initial SOC mineralized (SOC), and plant C retained in the soil (PCR) and sequestered C (PCR - SOC). The 30% residue soil cover after planting was achieved by the no-till and residue returned treatments and was not achieved by the chisel plow, residue removed treatment. In the 0- to 15-cm soil depth, the high yield zone had lower SOC (1.49 Mg ha) than the moderate yield zone (2.18 Mg ha), whereas in the 15- to 30-cm soil depth, SOC was higher in the 60% (1.38 Mg ha) than the 0% (0.82 Mg ha) residue removal treatment. When the 0- to 15- and 15- to 30-cm soil depths were combined, (i) 0.91 and 3.62 Mg SOC ha were sequestered in the 60 and 0% residue removal treatments; (ii) 2.51 and 0.36 Mg SOC ha were sequestered in the no-till and chisel plow treatments, and (iii) 1.16 and 1.65 Mg SOC ha were sequestered in the moderate and high yield zone treatments, respectively. The surface treatments influenced C cycling in the 0- to 15- and 15- to 30-cm depths but did not influence SOC turnover in the 30- to 60-cm depth.

RNAseq reveals weed-induced PIF3-like as a candidate target to manipulate weed stress response in soybean.

Weeds reduce yield in soybeans (Glycine max) through incompletely defined mechanisms. The effects of weeds on the soybean transcriptome were evaluated in field conditions during four separate growing seasons. RNASeq data were collected from six biological samples of soybeans growing with or without weeds. Weed species and the methods to maintain weed-free controls varied between years to mitigate treatment effects, and to allow detection of general soybean weed responses. Soybean plants were not visibly nutrient- or water-stressed. We identified 55 consistently downregulated genes in weedy plots. Many of the downregulated genes were heat shock genes. Fourteen genes were consistently upregulated. Several transcription factors including a PHYTOCHROME INTERACTING FACTOR 3-like gene (PIF3) were included among the upregulated genes. Gene set enrichment analysis indicated roles for increased oxidative stress and jasmonic acid signaling responses during weed stress. The relationship of this weed-induced PIF3 gene to genes involved in shade avoidance responses in Arabidopsis provide evidence that this gene may be important in the response of soybean to weeds. These results suggest that the weed-induced PIF3 gene will be a target for manipulating weed tolerance in soybean.

Physiological responses related to increased grain yield under drought in the first biotechnology-derived drought-tolerant maize.

Maize (Zea mays ssp. mays L.) is highly susceptible to drought stress. This work focused on whole-plant physiological mechanisms by which a biotechnology-derived maize event expressing bacterial cold shock protein B (CspB), MON 87460, increased grain yield under drought. Plants of MON 87460 and a conventional control (hereafter 'control') were tested in the field under well-watered (WW) and water-limited (WL) treatments imposed during mid-vegetative to mid-reproductive stages during 2009-2011. Across years, average grain yield increased by 6% in MON 87460 compared with control under WL conditions. This was associated with higher soil water content at 0.5 m depth during the treatment phase, increased ear growth, decreased leaf area, leaf dry weight and sap flow rate during silking, increased kernel number and harvest index in MON 87460 than the control. No consistent differences were observed under WW conditions. This indicates that MON 87460 acclimated better under WL conditions than the control by lowering leaf growth which decreased water use during silking, thereby eliciting lower stress under WL conditions. These physiological responses in MON 87460 under WL conditions resulted in increased ear growth during silking, which subsequently increased the kernel number, harvest index and grain yield compared to the control.

Denitrification kinetics in biomass- and biochar-amended soils of different landscape positions.

Knowledge of how biochar impacts soil denitrification kinetics as well as the mechanisms of interactions is essential in order to better predict the nitrous oxide (N2O) mitigation capacity of biochar additions. This study had multiple experiments in which the effect of three biochar materials produced from corn stover (Zea mays L.), ponderosa pine wood residue (Pinus ponderosa Douglas ex Lawson and C. Lawson), switchgrass (Panicum virgatum L.), and their corresponding biomass materials (corn stover, ponderosa pine wood residue, and switchgrass) on cumulative N2O emissions and total denitrification in soils from two different landscape positions (crest and footslope) were studied under varying water-filled pore space (40, 70, and 90% WFPS). Cumulative N2O emissions were reduced by 30 to 70% in both crest and footslope soils. The effect of biochars and biomass treatments on cumulative N2O emissions and total denitrification were only observed at ≥40% WFPS. The denitrification enzyme activity (DEA) kinetic parameters, K s (half-saturation constant), and V max (maximum DEA rate) were both significantly reduced by biochar treatments, with reductions of 70-80% in footslope soil and 80-90 % in the crest soil. The activation energy (E a) and enthalpy of activation of DEA (ΔH) were both increased with biochar application. The trends in DEA rate constants (K s and V max) were correlated by the trends of thermodynamic parameters (activation energy E a and enthalpy of activation ΔH) for denitrifying enzyme activity (DEA). The rate constant V max/K s evaluated the capacity of biochars to mitigate the denitrification process. Denitrifying enzyme kinetic parameters can be useful in evaluating the ability of biochars to mitigate N2O gas losses from soil.

Molecular characterization of biochars and their influence on microbiological properties of soil.

The tentative connection between the biochar surface chemical properties and their influence on microbially mediated mineralization of C, N, and S with the help of enzymes is not well established. This study was designed to investigate the effect of different biomass conversion processes (microwave pyrolysis, carbon optimized gasification, and fast pyrolysis using electricity) on the composition and surface chemistry of biochar materials produced from corn stover (Zea mays L.), switchgrass (Panicum virgatum L.), and Ponderosa pine wood residue (Pinus ponderosa Lawson and C. Lawson) and determine the effect of biochars on mineralization of C, N, and S and associated soil enzymatic activities including esterase (fluorescein diacetate hydrolase, FDA), dehydrogenase (DHA), ß-glucosidase (GLU), protease (PROT), and aryl sulfatase (ARSUL) in two different soils collected from footslope (Brookings) and crest (Maddock) positions of a landscape. Chemical properties of biochar materials produced from different batches of gasification process were fairly consistent. Biochar materials were found to be highly hydrophobic (low H/C values) with high aromaticity, irrespective of biomass feedstock and pyrolytic process. The short term incubation study showed that biochar had negative effects on microbial activity (FDA and DHA) and some enzymes including ß-glucosidase and protease.

Life-cycle assessment of the beef cattle production system for the northern great plains, USA.

A life-cycle assessment (LCA) model was developed to estimate the environmental impacts associated with four different U.S. Northern Great Plains (NPG) beef production systems. The LCA model followed a "cradle-to-gate" approach and incorporated all major unit processes, including mineral supplement production. Four distinct operation scenarios were modeled based on production strategies common to the NGP, and a variety of impacts were determined. The scenarios include a normal operation, early weaning of the calf, fast-tack backgrounding, and grassfed. Enteric emissions and manure emissions and handling were consistently the largest contributors to the LCA impacts. There was little variability between production scenarios except for the grassfed, where the greenhouse gas (GHG) emissions were 37% higher due to a longer finishing time and lower finishing weight. However, reductions to GHG emissions (15-24%) were realized when soil organic carbon accrual was considered and may be a more realistic estimate for the NGP. Manure emissions and handing were primary contributors to potential eutrophication and acidification impacts. Mitigation strategies to reduce LCA impacts, including diet manipulation and management strategies (i.e., treatment of manure), were considered from a whole-systems perspective. Model results can be used for guidance by NGP producers, environmental practitioners, and policymakers.

Validation of blood and liver oxymorphone analysis using LC-MS-MS: concentrations in 30 fatal overdoses.

A sensitive liquid chromatography-tandem mass spectrometry method was developed and validated for the quantitation of oxymorphone (OM) in human whole blood and liver. Sample preparation was done by solid-phase extraction, using deuterated OM as the internal standard. Separation was achieved using a Waters Aquity UPLC HSS T3 column. Analysis utilized positive electrospray ionization and multiple reaction monitoring. As part of the validation, studies were conducted to determine potential interference, selectivity, ion suppression/enhancement and carryover. Calibration model, limit of detection (LOD), lower limit of quantitation (LLOQ), precision and accuracy were also established. The linear range of the method was 2-500 ng/mL in blood and 5-500 ng/g in the liver. The LOD and LLOQ were 2 ng/mL for blood and 5 ng/g for the liver. Blood and/or liver specimens from 30 cases were analyzed. OM concentrations ranged from 23 to 554 ng/mL ( , n = 26) in blood and 48 to 1740 ng/g ( , n = 30) in the liver.

Anomalies in the asymmetric transfer hydrogenation of several polycyclic meso compounds.

Over the course of developing a multigram scale preparation of epoxy quinol 1 via asymmetric transfer hydrogenation (ATH) using the Noyori Ru(arene)(S,S-TsDPEN) catalysts, we observed several unexpected phenomena, including (i) chemoselective alkene vs ketone reduction of an enedione, (ii) a significant arene ligand effect (p-cymene vs. mesitylene) on the reaction pathway, and (iii) solvent-based reversal of the sense of enantioinduction.

Characteristics of alprazolam-related deaths compiled by a centralized state medical examiner.

BACKGROUND AND OBJECTIVE: Unintentional drug poisoning deaths represent a major health concern, particularly in rural areas. Although alprazolam is frequently detected in drug-related deaths, characterization of its involvement is limited. Our objective was to compare the characteristics of alprazolam-related deaths with nonalprazolam deaths in a predominantly rural state. METHODS: A comprehensive forensic drug database (FDD) was developed in 2005 to compile demographic, toxicology, and co-morbidity information from all West Virginia (WV) drug-related deaths. All FDD data from 2005 to mid-November 2007 were analyzed. RESULTS: Alprazolam contributed to 204 (17.0%) of the 1,199 drug-related deaths and was identified in 7.2% of the 363 deaths occurring during 2005 and in 27.5% of the 422 deaths entered in the database during 2007. At least one other drug, predominantly an opioid, was identified in 97.5% of the alprazolam cases, with concurrent benzodiazepines also found. Compared to nonalprazolam deaths, alprazolam decedents were significantly more likely to be obese and to have preexisting cardiovascular disease, but were less likely to have documented substance abuse. An alprazolam prescription existed in 52.5% of the alprazolam deaths, with 77.6% having a prescription for all drugs identified. CONCLUSIONS: Alprazolam was a contributing cause of death in a substantial and increasing number of drug-related deaths. Prescriptions for alprazolam and the other drugs detected were often present in these cases. SCIENTIFIC SIGNIFICANCE: Controlled substance monitoring programs should be routinely used as one mechanism to help prevent potential drug misuse/abuse. Our findings provide a baseline for ongoing alprazolam-related death surveillance.

Efficient, scalable asymmetric synthesis of an epoxy quinol via Noyori desymmetrization of a meso diketone.

Epoxy quinol 1a was prepared on a multi-gram scale by Noyori transfer hydrogenative desymmetrization of the readily available meso epoxy diketone 4. Although the intrinsic enantioselectivity for the desymmetrization was modest (82:18 er at 4% conversion), a highly enantiopure product (99.6:0.4 er) could be obtained in one operation in 44% yield via kinetic resolution of the minor enantiomer with long reaction times (48 h), or in 73% yield by combination with an enzymatic resolution of a 93:7 er mixture.

Biomass estimation approach impacts on calculated soil organic carbon maintenance requirements and associated mineralization rate constants.

To reduce atmospheric CO(2) concentrations and provide food for a growing world population, sustainable management practices must be adopted. An important consideration in the development of sustainable practices is the maintenance of soil organic carbon (SOC). Critical assumptions, with unknown errors, are used to calculate SOC maintenance requirements. This study investigated the impact of three approaches for estimating belowground nonharvested carbon (NHC) on SOC maintenance requirements, SOC and nonharvested C mineralization rate constants, and the capacity of the soil to sequester carbon. Common protocols were used to develop databases from eight historical carbon studies. The SOC to CO(2) (k(SOC)) and NHC to SOC (k(NHC)) rate constants were calculated using the model NHC(a)/SOC(i) = k(SOC)/k(NHC) + dSOC/dt(1/k(NHC)SOC(i)), where NHC(a) is the amount of applied NHC, SOC(e) is SOC at the equilibrium point, t = time, and SOC(i) is the initial SOC value. Analysis showed that (i) despite the difficulty in measuring belowground biomass, it is needed to calculate the SOC and NHC mineralization rate constants when using nonisotopic approaches; (ii) decreasing NHC by reducing the relative contribution of roots to NHC reduced the calculated SOC maintenance requirements and the amount of corn stover that could be sustainably harvested; iii) changes in the belowground NHC calculation approach do not result in a consistent impact on calculated rate constants; iv) changes in the belowground NHC calculation approach had a minimal impact on the calculated carbon sequestration potential (k(NHC)NHC)/k(SOC); (v) SOC at the beginning of the experiments was negatively correlated with temperature, while k(SOC) was positively correlated with tillage intensity; and (vi) the k(SOC) and k(NHC) rate constants can be used to directly assess the impact of different management scenarios on carbon turnover.

Fatality involving the ingestion of phenazepam and poppy seed tea.

Phenazepam is a benzodiazepine derivative that has been in clinical use in Russia since 1978 and is not available by prescription in the United States; however, it is attainable through various internet websites, sold either as tablets or as a reference grade crystalline powder. Presented here is the case of a 42-year old Caucasian male who died as the result of combined phenazepam, morphine, codeine, and thebaine intoxication. A vial of white powder labeled "Phenazepam, Purity 99%, CAS No. 51753-57-2, Research Sample", a short straw, and several poppy seed pods were found on the scene. Investigation revealed that the decedent had a history of ordering medications over the internet and that he had consumed poppy seed tea prior to his death. Phenazepam, morphine, codeine, and thebaine were present in the blood at 386, 116, 85, and 72 ng/mL, respectively.

Comparison of oxycodone in vitreous humor and blood using EMIT screening and gas chromatographic-mass spectrometric quantitation.

Vitreous humor may serve as a useful alternative specimen for oxycodone analysis in death investigations where blood samples are not available or are of poor quality or limited quantity. The purpose of this study was to investigate the relationship between immunoassay results and gas chromatography-mass spectrometry (GC-MS) quantitation of oxycodone in postmortem vitreous humor and blood. When used with vitreous humor calibrators, the Microgenics DRI Oxycodone (EMIT) Assay was found to be linear from 25 to 500 ng/mL with an limit of detection of 25 ng/mL. Vitreous humor and postmortem blood precipitate immunoassay responses in 57 oxycodone-positive cases were found to be correlated (r(2) = 0.69, p < 0.01). Confirmation and quantitation of oxycodone in vitreous humor by GC-MS was linear from 50 to 1000 ng/mL with a limit of detection of 10 ng/mL and a limit of quantitation of 50 ng/mL. In 30 cases, oxycodone vitreous humor concentrations ranged from less than 50 to 945 ng/mL, and blood concentrations ranged from 103 to 768 ng/mL. The average vitreous humor/blood ratio was 1.16 and ranged from 0.12 to 3.26. Disparities between vitreous fluid and blood oxycodone concentrations were seen in a few cases.