Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 29
Filter
1.
Conserv Physiol ; 9(1): coaa116, 2021.
Article in English | MEDLINE | ID: mdl-34676079

ABSTRACT

Declining wild populations combined with accumulating captive populations of e.g. livestock, pets, draught and zoo animals have resulted in some threatened species with substantial proportions of their populations in captivity. The interactions animals have with humans in captivity depend on handler familiarity and relationship quality and can affect animal health, growth and reproduction with consequences for the success of conservation programmes. However, assessments of how specific human-animal relationships affect a range of physiological and behavioural outcomes are rare. Here, we studied semi-captive Asian elephants with detailed records of elephant-handler (mahout) relationships and veterinary management, allowing assessment of multiple welfare indicators in relation to specific mahout-elephant relationship lengths and mahout experience. These included measures of physiological stress (faecal glucocorticoid metabolite [FGM], heterophil:lymphocyte ratio [H:L]), muscle damage (creatine kinase [CK]), immunological health (total white blood cell count [TWBC]) and behaviour (response to mahout verbal commands). We found no evidence that FGM or H:L related to aspects of the mahout-elephant relationship. Longer overall mahout experience (i.e. years of being a mahout) was linked to increased muscle damage and inflammation, but the lengths of specific mahout-elephant relationships were inversely associated with muscle damage in working-age elephants. Elephants responded more to familiar mahouts in behavioural tasks and faster to mahouts they had known for longer. In summary, our results found little evidence that the mahout-elephant relationship affects physiological stress in this population based on FGM and H:L, but mahout experience and relationships were linked to other physiological responses (CK, TWBC), and elephants require behavioural adjustment periods following mahout changes.

2.
Sci Rep ; 7(1): 12790, 2017 10 06.
Article in English | MEDLINE | ID: mdl-28986546

ABSTRACT

As semiconductor electronics keep shrinking, functionality depends on individual atomic scale surface and interface features that may change as voltages are applied. In this work we demonstrate a novel device platform that allows scanning tunneling microscopy (STM) imaging with atomic scale resolution across a device simultaneously with full electrical operation. The platform presents a significant step forward as it allows STM to be performed everywhere on the device surface and high temperature processing in reactive gases of the complete device. We demonstrate the new method through proof of principle measurements on both InAs and GaAs nanowire devices with variable biases up to 4 V. On InAs nanowires we observe a surprising removal of atomic defects and smoothing of the surface morphology under applied bias, in contrast to the expected increase in defects and electromigration-related failure. As we use only standard fabrication and scanning instrumentation our concept is widely applicable and opens up the possibility of fundamental investigations of device surface reliability as well as new electronic functionality based on restructuring during operation.

3.
J Environ Radioact ; 60(3): 275-91, 2002.
Article in English | MEDLINE | ID: mdl-12054041

ABSTRACT

Concentrations of radionuclides were measured in soils from a grid of locations surrounding the US Department of Energy Waste Isolation Pilot Plant (WIPP) in southeastern New Mexico and from a grid on a reference site approximately 20 km southeast of the WIPP site. Each of the two grids has 16 sampling locations (grid nodes) systematically distributed within an area of 16.580 ha. Sampling was conducted prior to the arrival of the first waste shipment at WIPP. Thus, the 137Cs and 23,240Pu in the soil are expected to have been deposited as global fallout, although the Gnome Site, 8.8 km southwest of the WIPP, is also a potential source of 239,240Pu and fission products. The reference grid has significantly higher concentrations of fallout and natural radionuclides than the WIPP grid. Up to 80% of the total variability in radionuclide concentrations across the two grids is attributable to differences between grid nodes. Differences between replicates within a location account for 44-50% of the variability in concentrations of the uranium isotopes, but only 11-17% of the variability in the concentrations of the other radionuclides. Samples having similar abundance of radionuclides were spatially aggregated across the terrain. The activity concentrations of the radionuclides were strongly correlated with the concentrations of Al and Pb, and with the percentages of sand, silt and clay in the soil. Normalizing radionuclide concentrations to the concentration of Al or percent fine particles can help adjust for differences in soil textures among samples and facilitate the detection of gradients or temporal changes in soil concentrations.


Subject(s)
Radioactive Waste , Soil Pollutants, Radioactive/analysis , Aluminum/analysis , Environmental Monitoring , Lead Radioisotopes/analysis , New Mexico , Radioisotopes/analysis , Reference Values , Refuse Disposal
4.
Health Phys ; 81(6): 711-9, 2001 Dec.
Article in English | MEDLINE | ID: mdl-11725891

ABSTRACT

A study was undertaken to evaluate the performance of an advanced design broad energy germanium detector for the in vivo measurement of radionuclides in lungs. Relative counting efficiency, background, and sensitivity for lung counting arrays consisting of four, three, and two 80-mm-diameter by 20-mm-thick (80 x 20 mm) broad energy germanium detectors were simulated by collecting spectra with the single 80 x 20 mm broad energy germanium at each of four locations over a humanoid torso phantom. Regions of interest were evaluated for photon energies ranging from 17 to 1,500 keV. The 80 x 20 mm detector arrays were then benchmarked against a standard array of four 70-mm-diameter by 20-mm-thick (70 x 20 mm) broad energy germanium detectors. Since testing new equipment can be an expensive and time consuming process, an alternative approach, using Monte Carlo simulations instead of physical measurements, was also evaluated and compared to experimental data. With this approach, counting efficiency and minimum detectable amount were simulated for two sizes of germanium detectors (70 mm and 80 mm diameter) at four different crystal thicknesses (15, 20, 25, and 30 mm). For the experimental measurements, arrays consisting of three and four 80 x 20 mm broad energy germanium detectors resulted in an increase in counting efficiencies, relative to the standard array, at all photon energies. The greatest relative increase was observed for the four-detector array (24-35%). In contrast, counting efficiency decreased, relative to the standard array, by 24-28% with a two-detector array. Arrays consisting of two and three 80 x 20 mm broad energy germanium detectors resulted in decreased relative background at all photon energies, with the exception of the 946 keV photon for the three-detector array. The most significant decrease in background occurred with the two-detector array (28 to 40%), while background was increased by 18-43% for the four-detector array. Arrays consisting of three and four 80 x 20 mm broad energy germanium detectors resulted in increased relative sensitivity at all photon energies. The three-detector array provided the greatest sensitivity at photon energies below 344 keV. The four-detector array provided slightly better measurement sensitivity at photon energies greater than 344 keV. The two 80 x 20 mm detector array provided sensitivity unexpectedly comparable to the standard array. Monte Carlo predictions on how size affects counting efficiency and minimum detectable amount agreed well with the experimental results. From the Monte Carlo predictions, the effect of detector thickness on counting efficiency was unimportant at photon energies up to 60 keV and independent of detector diameter. At higher photon energies for both detector diameters, the counting efficiency decreased as the thickness decreased. The values of minimum detectable amount for the 70-mm and 80-mm diameter detectors did not differ by more than 15% at 17 keV or 20% at 60 keV when compared to detectors of equivalent thickness. Minimum detectable amount increased slightly at 17 keV and rose by approximately 52% at 660 keV, with decreases in thickness from 30 mm to 15 mm.


Subject(s)
Germanium , Lung/chemistry , Radioisotopes/analysis , Radiometry/instrumentation , Equipment Design , Humans , Monte Carlo Method
5.
J Adolesc Health ; 29(4): 267-70, 2001 Oct.
Article in English | MEDLINE | ID: mdl-11587910

ABSTRACT

OVERVIEW: Patients with anorexia nervosa have functional cardiac abnormalities secondary to their nutritionally depleted state. These abnormalities include decreased left ventricular (LV) mass and varying degrees of LV systolic dysfunction. Assessment of LV diastolic function and quantitative assessment of right ventricular function are not routinely performed. The myocardial performance index (MPI) is a relatively new, simple, quantitative measure of global myocardial function. The purpose of this study was to evaluate left and right ventricular function in 13 patients with anorexia nervosa with the MPI and compare it to more commonly used echocardiographic measures of ventricular function.


Subject(s)
Anorexia Nervosa/complications , Heart Diseases/diagnostic imaging , Heart Diseases/physiopathology , Ventricular Function/physiology , Adolescent , Echocardiography, Doppler , Electrocardiography , Female , Heart Function Tests , Humans , Male , Retrospective Studies , Time Factors
6.
Infect Immun ; 69(10): 6391-400, 2001 Oct.
Article in English | MEDLINE | ID: mdl-11553583

ABSTRACT

Nitric oxide (NO) produced from inducible NO synthase (iNOS) is an important component of host defense against intracellular pathogens. To understand how phagocytes deliver NO to ingested microorganisms while avoiding cytotoxicity, we set out to study the subcellular localization of iNOS within macrophages following phagocytosis. Confocal microscopy of immunostained cells showed that iNOS was located not only diffusely within cytoplasm but also in vesicles, as well as immediately adjacent to the peripheral cell membrane. This peripheral iNOS colocalized with the cortical actin cytoskeleton and was removed by the actin-depolymerizing drug cytochalasin B. Biochemical fractionation of RAW 264 macrophages showed that 32.75% (+/-5.11%; n = 3) of iNOS was present in a particulate fraction, which cosedimented with low-density cellular vesicles. Following phagocytosis of latex beads, zymosan, immunoglobulin G-coated beads, or complement-coated zymosan, submembranous cortical iNOS was not recruited to phagosomes, nor was there any relocalization of intracellular iNOS. Similarly, following phagocytosis of Salmonella enterica serovar Typhimurium there was no recruitment of iNOS to the Salmonella vacuole at any stage after internalization. NO mediated significant killing of intracellular S. enterica serovar Typhimurium in RAW macrophages treated with lipopolysaccharide and gamma interferon; this was evident 4 h after infection. Although not recruited to phagosomes, iNOS association with the submembranous cortical actin cytoskeleton is ideally suited to deliver NO to microbes in contact with the cell surface and may contribute to early killing of ingested Salmonella.


Subject(s)
Actins/metabolism , Macrophages, Peritoneal/enzymology , Nitric Oxide Synthase/metabolism , Phagosomes/metabolism , Animals , Cell Fractionation , Cells, Cultured , Macrophages, Peritoneal/cytology , Macrophages, Peritoneal/immunology , Macrophages, Peritoneal/microbiology , Mice , Microscopy, Fluorescence , Nitric Oxide Synthase Type II , Phagocytosis/immunology , Salmonella typhimurium/immunology
7.
Clin Exp Immunol ; 123(1): 42-8, 2001 Jan.
Article in English | MEDLINE | ID: mdl-11167996

ABSTRACT

The production of nitric oxide (NO) within neutrophils is an important element of the innate immune response. We have previously shown that cytokines (IL-1alpha, tumour necrosis factor-alpha and interferon-gamma) induce human neutrophils in buffy coat preparations to produce iNOS. In order to define better the exact requirements for iNOS production within human neutrophils, we have studied the conditions needed for the production of iNOS in purified neutrophils. In contrast to buffy coat preparations, purified neutrophils in suspension did not produce an increase in iNOS following addition of cytokines. However, when purified neutrophils were allowed to adhere to glass surfaces either uncoated or coated with fetal calf serum (FCS), plasma, fibronectin or laminin, there was an increase in the percentage of iNOS-positive cells. The addition of cytokines during adhesion of these cells increased this proportion further. This was most marked for glass alone and FCS-coated glass on which the proportion of iNOS-positive cells increased to 22.7% and 35.5%, respectively, a significant increase compared with cytokine-treated neutrophils in suspension. Neither transmigration through activated endothelial monolayers nor the addition of soluble intercellular adhesion molecule-1 to purified neutrophil suspensions increased the percentage of iNOS-positive cells following cytokine stimulation. Adhesion of neutrophils to surfaces coated with IgG or complement also failed to increase cytokine-induced iNOS production. We conclude that iNOS production in human neutrophils requires not only cytokine stimulation, but also additional stimuli from adhesion to a surface.


Subject(s)
Cell Adhesion/immunology , Neutrophils/enzymology , Neutrophils/immunology , Nitric Oxide Synthase/biosynthesis , Cell Movement/immunology , Cell Separation , Cell-Free System/immunology , Cells, Cultured , Centrifugation, Density Gradient , Complement C3b/metabolism , Cytokines/pharmacology , Endothelium, Vascular/cytology , Endothelium, Vascular/enzymology , Endothelium, Vascular/immunology , Glass , Humans , Immunoglobulin G/metabolism , Neutrophils/metabolism , Nitric Oxide Synthase Type II , Surface Properties , Umbilical Veins
8.
Nucleic Acids Res ; 26(21): 4828-36, 1998 Nov 01.
Article in English | MEDLINE | ID: mdl-9776741

ABSTRACT

For type I restriction systems, recently determined nucleotide sequences predict conserved amino acids in the subunit that is essential for restriction but not modification (HsdR). The conserved sequences emphasize motifs characteristic of the DEAD-box family of proteins which comprises putative helicases, and they identify a new candidate for motif IV. We provide evidence based on an analysis of Eco KI which supports both the relevance of DEAD-box motifs to the mechanism of restriction and the new definition of motif IV. Amino acid substitutions within the newly identified motif IV and those in six other previously identified DEAD-box motifs, but not in the original motif IV, confer restriction-deficient phenotypes. We have examined the relevance of the DEAD-box motifs to the restriction pathway by determining the steps permitted in vitro by the defective enzymes resulting from amino acid substitutions in each of the seven motifs. Eco KI purified from the seven restriction-deficient mutants binds to an unmethylated target sequence and, in the presence of AdoMet, responds to ATP by undergoing the conformational change essential for the pathway of events leading to DNA cleavage. The seven enzymes have little or no ATPase activity and no endonuclease activity, but they retain the ability to nick unmodified DNA, though at reduced rates. Nicking of a DNA strand could therefore be an essential early step in the restriction pathway, facilitating the ATP-dependent translocation of DNA, particularly if this involves DNA helicase activity.


Subject(s)
DNA Restriction Enzymes/genetics , DNA Restriction Enzymes/metabolism , Adenosine Triphosphatases/chemistry , Adenosine Triphosphatases/genetics , Adenosine Triphosphatases/metabolism , Adenosine Triphosphate/metabolism , Amino Acid Sequence , Amino Acid Substitution , Base Sequence , DNA Primers/genetics , DNA Restriction Enzymes/chemistry , DNA, Bacterial/genetics , DNA, Bacterial/metabolism , Escherichia coli/enzymology , Escherichia coli/genetics , Molecular Sequence Data , Mutagenesis, Site-Directed , Phenotype , Plasmids/genetics , Protein Conformation , Restriction Mapping
9.
EMBO J ; 15(8): 2003-9, 1996 Apr 15.
Article in English | MEDLINE | ID: mdl-8617247

ABSTRACT

One subunit of both type I and type III restriction and modification enzymes contains motifs characteristic of DEAD box proteins, which implies that these enzymes may be DNA helicases. This subunit is essential for restriction, but not modification. The current model for restriction by both types of enzyme postulates that DNA cutting is stimulated when two enzyme complexes bound to neighbouring target sequences meet as the consequence of ATP-dependent DNA translocation. For type I enzymes, this model is supported by in vitro experiments, but the predicted co-operative interactions between targets have not been detected by assays that monitor restriction in vivo. The experiments reported here clearly establish the required synergistic effect but, in contrast to earlier experiments, they use Escherichia coli K-12 strains deficient in the restriction alleviation function associated with the Rac prophage. In bacteria with elevated levels of EcoKI the co-operative interactions are obscured, consistent with co-operation between free enzyme and that bound at target sites. We have made changes in three of the motifs characteristic of DEAD box proteins, including motif III, which in RecG is implicated in the migration of Holliday junctions. Conservative changes in each of the three motifs impair restriction.


Subject(s)
Bacterial Proteins/genetics , Bacterial Proteins/metabolism , DNA Restriction Enzymes/metabolism , Amino Acid Sequence , Base Sequence , Binding Sites , Chromosomes, Bacterial/genetics , Cloning, Molecular , DNA, Bacterial/genetics , Escherichia coli/genetics , Escherichia coli/metabolism , Genes, Bacterial , Molecular Sequence Data , Mutation , Phenotype , Plasmids/genetics , Sequence Homology, Amino Acid
11.
Singap J Trop Geogr ; 4(2): 99-118, 1983 Dec.
Article in English | MEDLINE | ID: mdl-12339381

ABSTRACT

PIP: A demographic and spatial analysis of mortality in Freetown, Sierra Leone, is presented, with emphasis on data for the census years 1963 and 1974. Consideration is first given to the availability of data and their quality. The authors then examine geographic variations in mortality within the city, age- and sex-specific death rates, the major causes of death, and death certification.^ieng


Subject(s)
Age Factors , Cause of Death , Data Collection , Death Certificates , Geography , Mortality , Reproducibility of Results , Sex Factors , Urban Population , Africa , Africa South of the Sahara , Africa, Western , Demography , Developing Countries , Population , Population Characteristics , Population Dynamics , Research , Research Design , Sierra Leone , Vital Statistics
14.
J Reprod Med ; 25(4): 150-6, 1980 Oct.
Article in English | MEDLINE | ID: mdl-7001015

ABSTRACT

Oral contraceptives agents (OCA) have been in use for more than two decades, and at the present time, 150 to 200 million women are using the preparations. Apart from their gynecologic influence, the hormones have been shown to affect a number of metabolic and nutritional processes, some advantageously and others disadvantageously. Concern over the nutritional status of females consuming OCA prompted this review. Eight vitamins and three minerals were investigated. Contraceptive steroid ingestion was shown to depress the physiologic levels of six nutrients (riboflavin, pyridoxine, folacin, vitamin B12, ascorbic acid and zinc), elevate the levels of three others (vitamin K, iron and copper) and provide little or no change in one (alpha tocopherol) and questionable increases in another (vitamin A). It was concluded that females consuming OCA should pay particular attention to vitamin and mineral intake and, if warranted, consume physiologic supplements of needed nutrients.


PIP: The state of knowledge concerning the effects of OCs (oral contraceptives) and mineral metabolism is assessed. A review of the literature indicates that OCs depress the levels of Vitamin B2, or riboflavin, Vitamin B6, or pyridoxine, folacin, Vitamin B12, Vitamin C, or ascorbic acid, zinc and elevate levels of Vitamin K, copper, and iron. The ingestion of OCs produces little effect on Vitamin E, or alpha tocopherol. Findings on the effects of OC ingestion on Vitamin A are ambiguous. OC users have 50%-80% higher serum levels of Vitamin A than nonusers; however, OC users may have a greater need for Vitamin A than nonusers. The need for riboflavin may also be higher for OC users. OC users need more pyridoxine and riboflavin is needed to oxidize pyridoxine phosphate to pyridoxal phosphate. Most studies support the contention that OC usage leads to a deficiency of Vitamin B6. Approximately 80% of all women using OCs for 6 or more months experience abnormal typtophan metabolism. In order to correct this problem, 25 mg daily, or 12 times the normal daily requirement, is needed. Some investigators recommend givng this dosage to women, who experience abnormal tryptophan metabolism, while others warn that the long-term effects of such high dosages are unknown. Most investigators recommend that OC users, with Vitamin B12 or Vitamin C deficiencies, should be given supplementary vitamins.


Subject(s)
Contraceptives, Oral, Synthetic/pharmacology , Contraceptives, Oral/pharmacology , Nutritional Physiological Phenomena/drug effects , Ascorbic Acid/metabolism , Copper/metabolism , Female , Folic Acid/metabolism , Glutathione Reductase/blood , Humans , Iron/metabolism , Pyridoxine/metabolism , Riboflavin/metabolism , Vitamin A/blood , Vitamin B 12/blood , Vitamin K/metabolism , Zinc/metabolism
16.
J Gerontol ; 32(3): 286-90, 1977 May.
Article in English | MEDLINE | ID: mdl-850055

ABSTRACT

A world champion distance runner, age 77, was evaluated in various anthropometric, pulmonary, hematological, and cardiorespiratory measures. The subject held 14 recognized world records in track and distance running for competitors aged 74, 75, and 76 years and had 11 records pending for the 77-year-age category. He was the 1975 National AAU Master's class IV-b champion in the 400, 800, 1500, 5000 and 15,000 meter races. The results of the physiological measures taken exceeded those of a more sedentary population of comparable age, were similar to reported values for other Master athletes, and approached the standards noted for much younger runners. The largest age-related decrements were observed in measures of maximal heart rate, maximal pulmonary ventilation, and maximal oxygen consumption. The general reduction in aerobic power was attributed to a combination of pulmonary, circulatory, and metabolic factors in addition to training consideration.


Subject(s)
Aging , Running , Sports Medicine , Aged , Anthropometry , Blood Pressure , Cholesterol/blood , Heart Rate , Hematocrit , Hemoglobinometry , Humans , Male , Physical Endurance , Respiratory Function Tests , Triglycerides/blood
17.
J Pharm Sci ; 65(10): 1536-9, 1976 Oct.
Article in English | MEDLINE | ID: mdl-10409

ABSTRACT

Operating parameters are described for the qualitative and quantitative analysis of an isoniazid-pyridoxine hydrochloride mixture by high-pressure liquid chromatography. Each compound was chromatographed on an octadecyl column, using absolute methanol-water (60:40) (pH 2.5) containing 0.01 M dioctyl sodium sulfosuccinate. The flow rate was 2.0 ml/min (2500 psig), and the peaks were detected at 293 nm. The analysis was accomplished using ion-pair formation for effecting chromatographic separation. The time required for separation of the drug mixture is approximately 12 min with an accuracy of 1.17-0.30%.


Subject(s)
Isoniazid/analysis , Pyridoxine/analysis , Chromatography, High Pressure Liquid , Drug Combinations , Hydrogen-Ion Concentration , Methods
SELECTION OF CITATIONS
SEARCH DETAIL
...