Soil sample conservation from field to lab for heterotrophic respiration assessment.

We evaluated (1) whether the sample transport time could lead to a significant loss of carbon through microbial respiration and to a change of measured respiration rates, which can be a problem in areas difficult to access, with a long travel time from field to laboratory; (2) whether the method used to quantify heterotrophic respiration for agricultural soils is adequate for horizons that remain always water-saturated or close to saturation. Surface horizons and deep Bh of Amazonian podzols were sampled and kept under refrigeration to maintain moisture of sampling time. Incubations of aliquot of the same sample were initiated on the sampling day and 3, 6, 9 and 12 days after sampling. Other aliquots were conducted on a tension table to given water potential (60 cm H2O) prior to incubation.•Soil samples, whether disturbed or not, should not be dried but kept at sampling moisture in semi-open plastic bags under refrigeration at 4 °C, respiration monitoring must be conducted without prior water potential adjustment.•In such conditions,12 days between sampling and beginning of measurement did not affected respiration results.•The method used for agricultural soils gave different results and does not make sense for soils under perudic moisture regime.

Mitochondrial phosphoenolpyruvate carboxykinase (PEPCK-M) and serine biosynthetic pathway genes are co-ordinately increased during anabolic agent-induced skeletal muscle growth.

We aimed to identify novel molecular mechanisms for muscle growth during administration of anabolic agents. Growing pigs (Duroc/(Landrace/Large-White)) were administered Ractopamine (a beta-adrenergic agonist; BA; 20 ppm in feed) or Reporcin (recombinant growth hormone; GH; 10 mg/48 hours injected) and compared to a control cohort (feed only; no injections) over a 27-day time course (1, 3, 7, 13 or 27-days). Longissimus Dorsi muscle gene expression was analyzed using Agilent porcine transcriptome microarrays and clusters of genes displaying similar expression profiles were identified using a modified maSigPro clustering algorithm. Anabolic agents increased carcass (p = 0.002) and muscle weights (Vastus Lateralis: p < 0.001; Semitendinosus: p = 0.075). Skeletal muscle mRNA expression of serine/one-carbon/glycine biosynthesis pathway genes (Phgdh, Psat1 and Psph) and the gluconeogenic enzyme, phosphoenolpyruvate carboxykinase-M (Pck2/PEPCK-M), increased during treatment with BA, and to a lesser extent GH (p < 0.001, treatment x time interaction). Treatment with BA, but not GH, caused a 2-fold increase in phosphoglycerate dehydrogenase (PHGDH) protein expression at days 3 (p < 0.05) and 7 (p < 0.01), and a 2-fold increase in PEPCK-M protein expression at day 7 (p < 0.01). BA treated pigs exhibit a profound increase in expression of PHGDH and PEPCK-M in skeletal muscle, implicating a role for biosynthetic metabolic pathways in muscle growth.

Evaluation of the electrochemical behavior of pentachlorophenol by cyclic voltammetry on carbon paste electrode modified by humic acids.

Humic substances, or natural recalcitrant organic matter, have an important role in the environment for their plant nutritional functions or for their capability to control the mobility of xenobiotic substances, such as pesticides. To verify the electrochemical behavior of pentachlorophenol (PCP), cyclic voltammetry was used because of its versatility. The following two different electrodes were used: carbon paste electrode (CPE) and carbon paste electrode chemically modified with humic acid (HACMCPE). The results demonstrated that PCP was better accumulated at the HACMCPE electrode, as a consequence of a larger current signal than at the CPE electrode. Cyclic voltammograms showed oxidation steps of PCP itself and probable production of quinonelike compounds.

Influence of humic substances on the photolysis of aqueous pesticide residues.

The present work investigated the direct and indirect photolysis of pesticide residues (atrazine, imazaquin, iprodione), in aqueous solutions and under UV-visible radiation (280-480nm). Different kinds of humic substances (HS) were added to samples in order to evaluate their behaviour as possible photocatalysts and their effect on the photolysis of pesticides. The fulvic acids were purchased from the International Humic Substances Society, and they were added to samples in concentrations ranging from 1 to 150 mgl(-1). Titanium dioxide was used as the photocatalyst, in concentration ranging from 10 to 150 mgl(-1). Pesticides photolysis were measured by UV-visible absorption spectroscopy and differential pulse polarography with all used pesticides, reaching total degradation after 2h of irradiation, thus indicating a fast direct photolysis. Photocatalysis by TiO(2) could increase the pesticides photolysis rate up to 40%. This effect, however, was not observed for imazaquin photolysis. Again, except for imazaquin, HS presence showed a positive effect in increasing pesticide degradation, but only within specific concentration ranges (below 10mg l(-1) for iprodione and about 30mgl(-1) for atrazine). Above these ranges HS induce a decrease in the pesticides photolysis rate. Spin-trapping measurements by electronic paramagnetic resonance spectroscopy, using the spin-trap DMPO, showed that HS are able to photogenerate hydroxyl radicals, increasing the pesticides molecule degradation. However, the HS also react with the photogenerated hydroxyl radical, influencing the pesticide photolysis, leading to a decrease in the photolysis rate and causing it to be strongly dependent on the nature and concentration of residues in the water to be treated.

QSAR of the anticonvulsant enaminones; molecular modeling aspects and other assessments.

The enaminones represent potentially useful agents for the clinical treatment in generalized tonic-clonic seizures (Epilepsia, 1993, 34(6), 1141-1145, Biopharm. Drug Disp. 2003, 397-407). A regression analysis was performed to provide a quantitative structure-activity relationship (QSAR) correlation model for prediction of activity for the anticonvulsant enaminones. Molecular modeling was performed to determine the molecular confluence of the Unverferth model (J. Med. Chem. 1998, 41, 63-73) to the enaminones. Conclusions related to the sodium channel model were assessed.

The FLUKA code for space applications: recent developments.

The FLUKA Monte Carlo transport code is widely used for fundamental research, radioprotection and dosimetry, hybrid nuclear energy system and cosmic ray calculations. The validity of its physical models has been benchmarked against a variety of experimental data over a wide range of energies, ranging from accelerator data to cosmic ray showers in the earth atmosphere. The code is presently undergoing several developments in order to better fit the needs of space applications. The generation of particle spectra according to up-to-date cosmic ray data as well as the effect of the solar and geomagnetic modulation have been implemented and already successfully applied to a variety of problems. The implementation of suitable models for heavy ion nuclear interactions has reached an operational stage. At medium/high energy FLUKA is using the DPMJET model. The major task of incorporating heavy ion interactions from a few GeV/n down to the threshold for inelastic collisions is also progressing and promising results have been obtained using a modified version of the RQMD-2.4 code. This interim solution is now fully operational, while waiting for the development of new models based on the FLUKA hadron-nucleus interaction code, a newly developed QMD code, and the implementation of the Boltzmann master equation theory for low energy ion interactions.

Vulnerability to flooding: health and social dimensions.

This paper presents research results on the impacts that floods can have on the people affected, thus complementing the existing data on the monetary losses liable to occur in flood events. Both datasets should be used when deciding on investment in flood defence measures. We report on research on the vulnerability of flood-affected communities to adverse health effects, and the development of an index of community vulnerability based on extensive focus-group research and secondary-source census data.

The search for extraterrestrial intelligence.

As far as we know, humanity is alone in the Universe: there is no definite evidence for the existence of extraterrestrial life, let alone extraterrestrial civilizations (ETCs) capable of communicating or travelling over interstellar distances. Yet popular speculation about the existence of ETCs abounds, including reports of alien visitations either now or in the past. But there is a middle way. It is now possible to put limits on the existence of ETCs of varying capabilities, within arbitrary distances from the Solar System, and conceive of real-world strategies whereby we might communicate with ETCs, or they with us.

Cytokine production consequent to T cell--microglia interaction: the PMA/IFN gamma-treated U937 cells display similarities to human microglia.

Cognate interactions between human adult microglia and activated T lymphocytes induce the production of inflammatory cytokines. Since this interaction can occur in a non-antigen-dependent manner, it is relevant to a variety of CNS diseases where activated T cells, regardless of specificities, come into contact with microglia; these disorders include multiple sclerosis, trauma, stroke and Alzheimer's disease. A model cell line would facilitate studies of the engagement between T cells and human adult microglia, since the latter are difficult to obtain in substantial quantity or frequency. This study shows that the PMA/IFN gamma-treated U937 cell line shows similarities to microglia in its interaction with activated T lymphocytes, in that the production of tumor necrosis factor (TNF)-alpha, interleukin (IL)-4, IL-10 and IL-12 is induced. Morphological features and mechanisms of cytokine production resemble those observed in microglia--T cell co-cultures since CTLA-4 and CD40--CD40L blockades reduce TNF-alpha and IL-10 levels, while anti-CD23 inhibits IL-10 only in U937--T cell interactions. We propose that PMA/IFN gamma-treated U937 cells can serve as a model of human adult microglia to study cytokine generation in response to interactions with activated T cells.

A community-based collaboration to assess and improve medical insurance status and access to health care of Latino children.

OBJECTIVES: Despite eligibility for subsidized insurance, low-income Latino children are at high risk of being medically uninsured. The authors sought to understand and improve access to medical insurance for Latino children living in a California community of predominantly low-income immigrant families. METHODS: During the summer of 1999, trained women from the community conducted interviews in Spanish with 252 randomly selected mothers of 464 children younger than age 19. Mothers provided information about family demographics, children's medical insurance, health care access, and experiences obtaining and maintaining children's insurance. RESULTS: Most children (83.3%) were eligible for subsidized medical insurance (48.4% Medi-Cal eligible; 35.0% Healthy Families eligible). Twenty-eight percent of eligible children were not enrolled. Non-enrolled eligible children were older (median age 7) than enrolled children (median age 4) and more likely to be born outside the U.S. (22.2%) than enrolled children (4.8%). Among children ages 3-18, those not enrolled were less likely to have visited a doctor in the past 12 months (58% compared to 78.7%) and less likely to have a usual source of care (96.3% compared to 99.5%). Mothers of non-enrolled children were more likely than mothers of enrolled children to have less than seven years of education (47.8% compared to 36.4%). Families with non-enrolled children were more likely to report out-of-pocket medical expenses (84.1% compared to 53%). Families with non-enrolled children were more likely to report barriers to the enrollment process, such as problems providing required documents (39.7% compared to 15.1%), problems understanding Spanish forms (19.4% compared to 8.9%), and confusing paperwork (39.7% compared to 24.7%). Most mothers (75.9%) reported that community organizations provided very useful help with children's insurance enrollment. Almost half (48.6%) preferred to receive enrollment assistance from community organizations. Only 43.3% of mothers had heard of the Healthy Families program. CONCLUSIONS: To reach the majority of uninsured Latino children, community-based outreach and insurance application assistance are crucial. Most important, the process of applying for and maintaining coverage in Medi-Cal or Healthy Families must be simplified.

Development of a space radiation Monte Carlo computer simulation based on the FLUKA and ROOT codes.

This NASA funded project is proceeding to develop a Monte Carlo-based computer simulation of the radiation environment in space. With actual funding only initially in place at the end of May 2000, the study is still in the early stage of development. The general tasks have been identified and personnel have been selected. The code to be assembled will be based upon two major existing software packages. The radiation transport simulation will be accomplished by updating the FLUKA Monte Carlo program, and the user interface will employ the ROOT software being developed at CERN. The end-product will be a Monte Carlo-based code which will complement the existing analytic codes such as BRYNTRN/HZETRN presently used by NASA to evaluate the effects of radiation shielding in space. The planned code will possess the ability to evaluate the radiation environment for spacecraft and habitats in Earth orbit, in interplanetary space, on the lunar surface, or on a planetary surface such as Mars. Furthermore, it will be useful in the design and analysis of experiments such as ACCESS (Advanced Cosmic-ray Composition Experiment for Space Station), which is an Office of Space Science payload currently under evaluation for deployment on the International Space Station (ISS). FLUKA will be significantly improved and tailored for use in simulating space radiation in four ways. First, the additional physics not presently within the code that is necessary to simulate the problems of interest, namely the heavy ion inelastic processes, will be incorporated. Second, the internal geometry package will be replaced with one that will substantially increase the calculation speed as well as simplify the data input task. Third, default incident flux packages that include all of the different space radiation sources of interest will be included. Finally, the user interface and internal data structure will be melded together with ROOT, the object-oriented data analysis infrastructure system. Beyond the benefits of 'objectivity', ROOT's incorporation will also provide a graphical user interface with powerful tools for input prior to the calculation, as well as for data analysis and visualization of the results.

Functional outcome following surgical treatment of intra-articular distal humeral fractures through a posterior approach.

BACKGROUND: While surgical repair is considered the standard of care of displaced intra-articular distal humeral fractures, most investigators have assessed its results with use of surgeon-based and/or radiograph-based outcome measures. The purpose of our study was to determine the functional outcome of fixation of displaced intra-articular distal humeral fractures with use of a standardized evaluation methodology consisting of objective testing of muscle strength and use of patient-based questionnaires (both limb-specific and general health-status questionnaires). METHODS: We identified twenty-five patients (fourteen male and eleven female), with a mean age of forty-seven years, who had an isolated, closed, displaced, intercondylar, intra-articular fracture of the distal part of the humerus repaired operatively through a posterior approach and fixed with plates on both the medial and the lateral column. All patients returned for follow-up that included recording of a complete history, physical examination, radiographic examination, completion of both a limb-specific questionnaire (Disabilities of the Arm, Shoulder and Hand [DASH]) and a general health-status questionnaire (Short Form-36 [SF-36]), and objective muscle-strength testing. RESULTS: The mean duration of follow-up was thirty-seven months (range, eighteen to seventy-five months). The mean flexion contracture was 25 degrees (range, 5 to 65 degrees), and the mean arc of flexion-extension was 108 degrees (range, 55 to 140 degrees). Significant decreases in mean muscle strength compared with that on the normal side were seen in both elbow flexion measured at 90 degrees (74 percent of normal, p = 0.01) and elbow extension measured at 45 degrees (76 percent of normal, p = 0.01), 90 degrees (74 percent of normal, p = 0.01), and 120 degrees (75 percent of normal, p = 0.01). The mean DASH score was 20 points, indicating mild residual impairment. The SF-36 scores revealed minor but significant decreases in the role-physical and physical function scores (p = 0.01 and 0.03, respectively) but no alteration of the mental component or mean scores. Six patients (24 percent) had a reoperation; three of them had removal of prominent hardware used to fix the site of an olecranon osteotomy. CONCLUSIONS: The surgical repair of an intra-articular distal humeral fracture is an effective procedure that reliably maintains general health status as measured by patient-based questionnaires. Our study quantified a decrease in the range of motion and muscle strength of these patients, which may help to explain the mild residual physical impairment detected by the limb-specific outcome measures and physical function components of the general health-status measures.

Elevated zinc induces siderophore biosynthesis genes and a zntA-like gene in Pseudomonas fluorescens.

Zinc-regulated genes were analyzed in Pseudomonas fluorescens employing mutagenesis with a reporter gene transposon. Six mutants responded with increased gene expression to elevated concentrations of zinc. Genetic and biochemical analysis revealed that in four of the six mutants the transposon had inserted into genes essential for the biosynthesis of the siderophore pyoverdine. The growth of one of the mutants was severely impaired in the presence of elevated concentrations of cadmium and zinc ions. In this mutant, the transposon had inserted in a gene with high similarity to P-type ATPases involved in zinc and cadmium ion transport. Four mutants reacted with reduced gene expression to elevated concentrations of zinc. One of these mutants was sensitive to zinc, cadmium and copper ions. The genetic region targeted in this mutant did not show similarity to any known gene.

Cadmium-regulated gene fusions in Pseudomonas fluorescens.

To study the mechanisms soil bacteria use to cope with elevated concentrations of heavy metals in the environment, a mutagenesis with the lacZ-based reporter gene transposon Tn5B20 was performed. Random gene fusions in the genome of the common soil bacterium Pseudomonas fluorescens strain ATCC 13525 were used to create a bank of 5,000 P. fluorescens mutants. This mutant bank was screened for differential gene expression in the presence of the toxic metal cadmium. Fourteen mutants were identified that responded with increased or reduced gene expression to the presence of cadmium. The mutants were characterized with respect to their metal-dependent gene expression and their metal tolerance. Half the identified mutants reacted with differential gene expression specifically to the metal cadmium, whereas some of the other mutants also responded to elevated concentrations of copper and zinc ions. One of the mutants, strain C8, also showed increased gene expression in the presence of the solvent ethanol, but otherwise no overlap between cadmium-induced gene expression and general stress response was detected. Molecular analysis of the corresponding genetic loci was performed using arbitrary polymerase chain reaction (PCR), DNA sequencing and comparison of the deduced protein products with sequences deposited in genetic databases. Some of the genetic loci targeted by the transposon did not show any similarities to any known genes; thus, they may represent 'novel' loci. The hypothesis that genes that are differentially expressed in the presence of heavy metals play a role in metal tolerance was verified for one of the mutants. This mutant, strain C11, was hypersensitive to cadmium and zinc ions. In mutant C11, the transposon had inserted into a genetic region displaying similarity to genes encoding the sensor/regulator protein pairs of two-component systems that regulate gene expression in metal-resistant bacteria, including czcRS of Ralstonia eutropha, czrRS of Pseudomonas aeruginosa and copRS of Pseudomonas syringae. Although the P. fluorescens strain used in this study had not been isolated from a metal-rich environment, it nevertheless contained at least one genetic region enabling it to cope with elevated concentrations of heavy metals.

Evaluation of a test device to assess X-ray phototimers.

This article describes the evaluation of a commercial device designed to assess the performance of phototimers on x-ray systems. The device consists of a digital readout meter that can be connected to a radiographic or mammographic test cassette. Results showed that the device provided reproducible results with different x-ray generators and processors. The device can be used in acceptance testing and routine quality control inspections, as well as to calibrate or adjust phototimers.

Reduction of shock-induced gastric damage by a nitric oxide-releasing aspirin derivative: role of neutrophils.

The gastric damage associated with hemorrhagic shock appears to occur, at least in part, through neutrophil-dependent mechanisms. Nitric oxide (NO)-releasing derivatives of aspirin have been shown to spare the gastrointestinal tract of injury. As NO can inhibit neutrophil adherence, it is possible that such a derivative of aspirin (NCX-4016) would exert inhibitory effects on neutrophil adherence and therefore be capable of protecting the stomach against shock-induced gastric damage. This hypothesis was tested in this study. Oral administration of NCX-4016 or glyceryl trinitrate or depletion of circulating neutrophils with antineutrophil serum significantly reduced the extent of gastric damage induced by hemorrhagic shock, whereas aspirin had no effect. NCX-4016 and antineutrophil serum pretreatment resulted in significant preservation of gastric blood flow during the shock period. Moreover, NCX-4016, but not aspirin, was capable of inhibiting N-formyl-Met-Leu-Phe-induced leukocyte adherence to postcapillary mesenteric venules. These results suggest that an NO-releasing aspirin derivative reduces the susceptibility of the stomach to shock-induced damage through inhibitory effects on neutrophil adherence to the vascular endothelium.

Noninvasive measures of radiolabeled dextran transport in in situ rabbit lung.

UNLABELLED: Dextrans are nontoxic and can be obtained in a wide variety of molecular weights. The purpose of this study was to label 6-kDa and 40-kDa dextrans with gamma- (99mTc) and positron- (18F) emitting radioisotopes and monitor their transport across the pulmonary microvascular barrier. METHODS: External scan measurements for radiolabeled uncharged dextrans, albumin and red blood cells were obtained in eight blood-perfused in situ rabbit lung preparations. After 3 hr of external scanning, the lungs were removed for postmortem and extravascular distribution volume calculations. Extravascular distribution volumes were obtained in six additional rabbits following 4 hr of dextran perfusion to compare the effect of time. The normalized slope index (NSI), a measure of transvascular transport rate, was calculated for each diffusible tracer. RESULTS: The mean NSI for albumin (0.001676 +/- 0.000537 min-1) was significantly lower than NSI for the 40-kDa dextran (0.002303 +/- 0.0005426 min-1) as well as the 6-kDa dextran (0.004312 +/- 0.001134 min-1). The difference between the 6-kDa and the 40-kDa dextrans was also significant. After 4 hr of equilibration, distribution volumes were not significantly different than those obtained at 3 hr. CONCLUSION: Dextrans can be radiolabeled with gamma and positron emitters and small dextrans traverse the lung microvascular barrier more rapidly than albumin. Our results suggest that the use of small dextrans rather than albumin can reduce scan times in clinical applications and minimize motion artifact associated with the noninvasive gamma detection method.

Noninvasive measurements of albumin flux into lung interstitium with increased microvascular pressure.

The purpose of this study was to determine the effect of increasing left atrial pressure on noninvasive measurements of radiolabeled albumin normalized slope index (NSI). Using portable gamma scintillation detectors, we monitored radioactivities of 131I-labeled albumin and 51Cr-labeled red blood cells in the blood and over the lung of six anesthetized sheep before and 2 h after a 9- to 14-Torr increase in left atrial pressure. Measurements of NSI for 131I-albumin decreased > 50% after a step increase in left atrial pressure. We interpreted the data using a model that has been used to successfully describe unsteady-state lymph flow and protein concentrations after vascular pressure increases in sheep. Model predictions strongly suggest that the reduction in NSI is due to rapid fluid and solute removal from the interstitium via the lymphatics. The theoretical model was able to predict external scan data and lung lymph protein concentrations only when a change in lymphatic conductance (LI) or initial lymphatic pressure (P0) was imposed at the time of increased pressure. On average, model-predicted increases in LI were sevenfold, whereas predicted decreases in P0 were four- to fivefold. Imposed changes in LI and P0 opposed increases in interstitial fluid volume after increased pressure. This was consistent with normal-to-low postmortem measurements of bloodless wet-to-dry lung weight ratios. In summary, these results indicate that changes in the rate of fluid removal from the interstitium can significantly alter NSI, and in this case, NSI does not reflect pulmonary microvascular permeability. In sheep, increases in the lymphatics' ability to remove interstitial fluid may occur with relatively small increases in microvascular pressure.

A voice-operated method for administering the MMPI.

Paper/pencil psychological tests such as the Minnesota Multiphasic Personality Inventory (MMPI) are difficult to complete independently by patients with limited hand function. This paper describes a voice recognition system developed to allow patients with no hand function to take the MMPI independently. Profiles generated by this system are not statistically different from those generated by standard MMPI booklet format. Limitations and possible extensions of the system as it currently exists are discussed.