Mercury storage in surface soils in a central Washington forest and estimated release during the 2001 Rex Creek Fire

Recent investigations indicate that wildfires provide a significant flux of mercury (Hg) from terrestrial ecosystems to the atmosphere. However, little is known about how geographic location, climate, stand age, and tree species affect Hg accumulation prior to burning and loss during burning. Soil cores collected in sites burned during the summer 2001 Rex Creek Fire in the eastern Cascade Mountains (Washington State, USA) and in adjacent unburned control sites indicate that Hg loss from soils during the Rex Creek Fire averaged 6.7 (+/-2.5) g Hg ha(-1). This soil profile-based estimate of Hg release is higher than a previous estimate for the same fire based on airborne measurements of Hg and CO concentrations in smoke. This study has implications for global estimates of Hg storage in forests and release to the atmosphere during wildfires.     

A novel low-cost approach of implementing electrochemiluminescence detection for microfluidic analytical systems

This paper presents an inexpensive approach of implementing electrochemiluminescence (ECL) detection for microfluidic analytical systems. It consists in using printed circuit board (PCB) technology to design electrodes and sealing the epoxy substrate with a transparent microfluidic structure in polymer for ECL detection and system integration. A pair of PCB electrodes (10 mm²) and an ECL microfluidic device are designed and fabricated. They are tested via luminol ECL detection to quantify H₂O₂. Characterization of the PCB electrodes is performed via the determination of the optimum potential (0.7 V vs. Ag/AgCl) to trigger luminol oxidation. Electrode potential is square-wave modulated from 0 to 0.7 V at a minimum period of 17 s. Measurements of on/off modulated ECL signals for different H₂O₂ concentrations are carried out to establish their relationship. The obtained results show a 50-nM detection limit at a signal-to-noise ratio (SNR) equal to 3 and a linear range extending up to 0.1 mM in batch or in microfluidic conditions. The detection volumes for these two systems are 2 ml and 4 μl, respectively.     

Toward single molecule detection of staphylococcal enterotoxin B: mobile sandwich immunoassay on gliding microtubules

An immunoassay based on gliding microtubules (MTs) is described for the detection of staphylococcal enterotoxin B. Detection is performed in a sandwich immunoassay format. Gliding microtubules carry the antigen-specific "capture" antibody, and bound analyte is detected using a fluorescent viral scaffold as the tracer. A detailed modification scheme for the MTs postpolymerization is described along with corresponding quantification by fluorescence spectroscopy. The resultant antibody-MTs maintain their morphology and gliding capabilities. We report a limit of detection down to 0.5 ng/mL during active transport in a 30 min assay time and down to 1 ng/mL on static surfaces. This study demonstrates the kinesin/MT-mediated capture, transport, and detection of the biowarfare agent SEB in a microfluidic format.     

"Systematic empirical investigation of vulnerability to postpartum depression from a psychodynamic perspective": Reply to Besser et al.

I appreciate the thoughtful and constructive comments Besser et al. (see record 2008-03991-016) have offered regarding the original article (see record 2007-00135-004) and mention some thoughts for further consideration concerning the relationship between empirical research and clinical practice. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Glucose metabolism in lactating cows in response to isoenergetic infusions of propionic acid or duodenal glucose

A bibliographical study showed that increasing supplies of glucogenic nutrients lead to a curvilinear increase in milk and protein yield. Increased post-hepatic glucose availability may be involved in the increase in milk yield. In the present experiment, 5 dairy cows were arranged in a 5 x 5 Latin square design to compare the respective effects of 2 amounts of either duodenal glucose or ruminal propionic acid (C3) on glucose metabolism. Treatment consisted of a grass silage-based diet supplemented with glucogenic nutrients infused into the rumen as a mixture of volatile fatty acids (control) or C3 (6.5 and 13 mol/d) or as glucose (3.4 and 6.9 mol/d) infused into the duodenum. Treatments were isoenergetic and isonitrogenous and contained 100 and 115% of energy and protein requirements, respectively, according to the Institut National de la Recherche Agronomique. Glucose appearance rate (Ra) tended to increase with the level of infusions of both glucogenic materials and with the high dose of duodenal glucose. Plasma insulin-like growth factor-I (IGF-I) concentration increased with the infusion of glucogenic materials compared with the control and was significantly higher with glucose than with C3 treatments. This experiment did not indicate whether the increased Ra was the key mechanism to increased milk yield because milk yield only tended to increase and the standard error for Ra was high. With the high dose of glucose infused into the duodenum, the Ra increase was greater than the increased lactose production in milk. Because of that connection, IGF-I may also be involved by favoring the glucose utilization by the mammary gland.     

Correlation of the Taq1 dopamine D2 receptor gene and percent body fat in obese and screened control subjects: a preliminary report

While there is a considerable body of literature correlating the role of dopaminergic genes and obesity, body mass index, body type, overeating, carbohydrate binging, energy expenditure and low dopamine D2 receptor (D2R) receptor density, there is a paucity of research concerning the dopamine D2 receptor gene (DRD2) variants and percent body fat. We report here the potential association of DRD2 genotypes and the percent fat phenotype. In this study we genotyped 122 obese/overweight (O/OW) Caucasian subjects and 30 non-obese Caucasian controls, screened to exclude substance abuse. The subjects were assessed for weight, body mass index (BMI; kg m(-2)) and percent body fat using dual energy X-ray absorptiometry (DEXA). The sample was separated into two independent groups; those with the Taq1 A1 allele (A1/A1 or A1/A2) and those without the A1 allele (A2/A2). The controls had a normal range of body fat (25-31% for females and 18-25% for males). The O/OW subjects had a percent body fat value of over 32% for females and over 25% for males. For the O/OW subjects, the mean BMI was 29.3 ± 6.25 kg m(-2), mean body fat was 42.1 ± 7.5% and mean weight was 82.7 ± 21.7 kg. The DRD2 Taq1 A1 allele was present in 67% of the O/OW subjects compared to 3.3% of super controls (A group), 33.3% of screened (for drug abuse and obesity) controls (B group) and unscreened literature controls 29.4% (P≤ 0.001). Comparing all cases with more than 34% body fat, utilizing logistic regression analysis, the DRD2 A1 allele accounts for 45.9% of the variance, which is statistically significant (χ(2) = 43.47, degrees of freedom (df) = 1, P < 0.0001). These results are consistent with a role for the DRD2 gene in obesity, as measured by percent body fat as well as by weight and BMI.     

Protein synthesis in jejunum and liver of neonatal calves fed vitamin A and lactoferrin

Rates of protein synthesis (PS) and turnover are more rapid during the neonatal period than during any other stage of postnatal life. Vitamin A and lactoferrin (Lf) can stimulate PS in neonates. However, newborn calves are vitamin A deficient and have a low Lf status, but plasma vitamin A and Lf levels increase rapidly after ingestion of colostrum. Neonatal calves (n = 6 per group) were fed colostrum or a milk-based formula without or with vitamin A, Lf, or vitamin A plus Lf to study PS in the jejunum and liver. l-[¹³C]Valine was intravenously administered to determine isotopic enrichment of free (nonprotein-bound) Val (AP_Free) in the protein precursor pool, atom percentage excess (APE) of protein-bound Val, fractional protein synthesis rate (FSR) in the jejunum and liver, and isotopic enrichment of Val in plasma (APE_Pla) and in the CO₂ of exhaled air (APE_Ex). The APE, AP_Free, and FSR in the jejunum and liver did not differ significantly among groups. The APE_Ex increased, whereas APE_Pla decreased over time, but there were no group differences. Correlations were calculated between FSR_Jej and histomorphometrical and histochemical data of the jejunum, and between FSR_Liv and blood metabolites. There were negative correlations between FSR_Liv and plasma albumin concentrations and between FSR_Jej and the ratio of villus height:crypt depth, and there was a positive correlation between FSR_Jej and small intestinal cell proliferation in crypts. Hence, there were no effects of vitamin A and Lf and no interactions between vitamin A and Lf on intestinal and hepatic PS. However, FSR_Jej was correlated with histomorphometrical traits of the jejunum and FSR_Liv was correlated with plasma albumin concentrations.     

Visualizing resonance energy transfer in supramolecular surface patterns of β-CD-functionalized quantum dot hosts and organic dye guests by fluorescence lifetime imaging

Detection of an analyte via supramolecular host-guest binding and quantum dot (QD)-based fluorescence resonance energy transfer (FRET) signal transduction mechanism is demonstrated. Surface patterns consisting of CdSe/ZnS QDs functionalized at their periphery with β-cyclodextrin (β-CD) were obtained by immobilization of the QDs from solution onto glass substrates patterned with adamantyl-terminated poly(propylene imine) dendrimeric "glue." Subsequent formation of host-guest complexes between vacant β-CD on the QD surface and an adamantyl-functionalized lissamine rhodamine resulting in FRET was confirmed by fluorescence microscopy, spectroscopy, and fluorescence lifetime imaging microscopy (FLIM).     

A vocabulary for medical informatics

The terminology in medical informatics is evolving rapidly. The organizers of MEDINFO and SCAMC have used different sets of keywords to index their documents. Recognizing the limitations of this approach, members of those organizations joined with the National Library of Medicine in the creation of a better terminology for medical informatics. A hierarchical structure was placed on the terms to produce a thesaurus typical of the sort often used in the indexing and retrieving of documents. The building of this thesaurus began with an automatic merging of the thesaurus used by the Association of Computing Machinery and the Information Sciences component of the "Medical Subject Headings." This product was pruned by eliminating terms not related to those in the MEDINFO keyword list or not in the medical informatics literature. Further refinement of the thesaurus resulted from extensive discussions among the authors of this paper. The first major application of this terminology has been to the indexing of the articles in "MEDINFO-86 Proceedings." Major components of this medical informatics thesaurus also have been incorporated into the "Medical Subject Headings." This paper describes the process of preparing the thesaurus and presents an evaluation of its coverage of the "MEDINFO-86 Proceedings."