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Hepcidin, the Fe-regulatory peptide, has been shown to inhibit Fe absorption and reticuloendothelial Fe recycling. The present study was conducted to explore the mechanism of in vivo Fe regulation through genetic disruption of hepcidin1 and acute effects of hepcidin treatment in hepcidin1 knockout (Hepc1− / − ) and heterozygous mice. Hepcidin1 disruption resulted in significantly increased intestinal Fe uptake. Hepcidin injection inhibited Fe absorption in both genotypes, but the effects were more evident in the knockout mice. Hepcidin administration was also associated with decreased membrane localisation of ferroportin in the duodenum, liver and, most significantly, in the spleen of Hepc1− / − mice. Hypoferraemia was induced in heterozygous mice by hepcidin treatment, but not in Hepc1− / − mice, 4 h after injection. Interestingly, Fe absorption and serum Fe levels in Hepc1− / − and heterozygous mice fed a low-Fe diet were not affected by hepcidin injection. The present study demonstrates that hepcidin deficiency causes increased Fe absorption. The effects of hepcidin were abolished by dietary Fe deficiency, indicating that the response to hepcidin may be influenced by dietary Fe level or Fe status.
We observed several H ii regions in the dwarf irregular galaxy NGC 6822 using the infrared spectrograph on the Spitzer Space Telescope. Our aim is twofold: first, to examine the neon to sulfur abundance ratio in order to determine how much it may vary and whether or not, it is fairly ‘universal’; second, to discriminate and test the predicted ionizing spectral energy distribution between various stellar atmosphere models by comparing with our derivation of the ratio of fractional ionizations involving neon and sulfur. This work extends our previous similar studies of H ii regions in M83 and M33 to lower metallicities.
Evidence of past zoonotic infection was investigated serologically in randomly selected Northern Ireland farmers. The percentage of farmers with antibody was: Brucella abortus (0·7), Leptospira interrogans serovars (8·1), Borrelia burgdorferi (14·3), Toxoplasma gondii (73·5), Coxiella burnetii (28·0), Chlamydia psittaci (11·1) and Hantavirus (1·2).
The results show that Northern Ireland farmers have been exposed in the past to zoonotic infections. It is not known if these infections contributed to ill health in farmers but it is now time for the health of farm workers and their medical services to be reassessed.
Haem carrier protein 1 (HCP1) was originally identified and characterised as a mammalian haem transporter. However, recent evidence has shown that it is also a proton-coupled folate transporter (PCFT) and mutations in the gene cause hereditary folate deficiency in humans. We therefore investigated haem and folate transport characteristics of PCFT/HCP1 both in vivo and in vitro in CD-1 mice and in the presence or absence of a blocking antibody for PCFT/HCP1, and also in cultured cells (which express PCFT/HCP1 endogenously) to elucidate the specificity and selectivity of PCFT/HCP1. The in vivo study showed that the addition of folic acid inhibited 59Fe-labelled haem transport in hypoxic mice but had no effect in normal mice. Using in vitro methods, the results showed increased [3H]folate uptake into everted duodenum from hypoxic mice but uptake was reduced by the addition of haem or PCFT/HCP1 antibodies to the medium. Caco-2 cells transiently transfected with small interfering RNA (siRNA) PCFT/HCP1 duplex oligos resulted in a 69 % reduction in PCFT/HCP1 mRNA when compared with the control siRNA. Both haem and folate uptake were significantly (P < 0·05) reduced in cells transfected with PCFT/HCP1 siRNA; however, the magnitude of reduction with folic acid uptake was greater (48 %) than that of haem (22·5 %). Overall the data support PCFT/HCP1 as a primary folate transporter with a lower affinity for haem. PCFT/HCP1 could therefore play a physiological role in Fe nutrition and the data highlight the potential for the interaction of folate and haem at the level of intestinal absorption.
An elongated ERO with R - K′ = 7.5 behind the cluster A851 at z=0.4 was found to lie at z = 1.5 both by the photometric redshift and by a cross correlation method of its H-band SED with local E/SO spectra. the luminosity profile is well represented by a seeing convolved exponential disk, and the lack of redshifted H-alpha emission indicates that it has a dynamically relaxed disk with an old stellar population. Gravitational lensing of the cluster is not strong enough to stretch the image and cannot convert the de Vaucouleurs law into an exponential law.
Volatile organic compounds (“VOCs”) are widely used in industrial process, transportation fuels, and households. It is inevitable that some VOCs will escape into the atmosphere. Emission of VOCs will cause three major problems, including (1) increased exposure level of the population to know carcinogenic compounds such as benzene and carbon tetrachloride, (2) increased ozone concentration in the atmosphere at ground level, and (3) stratospheric depletion of the ozone layer, which alters global climate and increases exposure to UV radiation. Reducing the concentrations of VOCs will greatly improve air quality. A common method for VOC removal is catalytic decomposition. Most works have only focus on reducing VOC concentrations down to a few parts per million (ppm). Very little research has been conducted on reducing the VOCs down to parts per billion (ppb) levels, or less. This paper reports the decomposition of VOCs using a unique class of nanofibrous bird's-nest superstructure material. This open-inter-woven nanofibrous superstructure provides superb host for catalytic reactions and permits relatively easy flow of the gas stream through the structure. The nanofibrous MnO2 is highly effective in destroy more than 50 VOCs on USEPA's top priority list toxic VOCs to ppb level or less at a 200 − 350°C temperature.
The constant initial speed of propagation (V) of heavy gravity currents, of density ρC,
released from behind a lock and along the bottom boundary of a tank containing a
linearly stratified fluid has been measured experimentally and calculated numerically.
The density difference, bottom to top, of the stratification is (ρb−ρ0) and its intrinsic
frequency is N. For a given ratio of the depth of released fluid (h) to total depth (H)
it has been found that the dimensionless internal Froude number, Fr = V/NH, is
independent of the length of the lock and is a logarithmic function of a parameter
R = (ρC−ρ0)/(ρb−ρ0), except at small values of h/H and R close to unity. This
parameter, R, is one possible measure of the relative strength of the current (ρC−ρ0)
and stratification (ρb−ρ0). The distance propagated by the current before this constant
velocity regime ended (Xtr), scaled by h, has been found to be a unique function of
Fr for all states tested. After this phase of the motion, for subcritical values of Fr, i.e.
less than 1/π, internal wave interactions with the current resulted in an oscillation of
the velocity of its leading edge. For supercritical values, velocity decay was monotonic
for the geometries tested. A two-dimensional numerical model incorporating a no-slip
bottom boundary condition has been found to agree with the experimental velocity
magnitudes to within ±1:5%.
Two layer co-sputtered Bi over In thin films (40 nm/layer) act as a microfabrication resist with many potential applications. Their physical, chemical and optical characteristics change after laser exposures that produce a rapid thermal anneal in selected areas. Unlike organic photoresists, Bi/In is a bimetallic thermal resist whose sensitivity shows a near wavelength invariance for wavelengths from Near IR to UV. The laser-induced patterns are developed by an etch that selectively removes unexposed areas and retains converted ones. The optical density (OD) of 40 nm thick Bi/In films on quartz substrates, for example, changes from 3.3 OD to 0.37 OD in the annealed area. This has enabled the creation of direct-write photomasks for standard photoresist exposures. In this paper, the composition, morphology, and nanostructure of the resist before and after laser processing were studied in order to determine the mechanism of the laser-induced material conversion. AFM, XRD, and TEM show that the as-deposited films are polycrystalline, continuous, but with a rough, island morphology. Furnace anneals in air above the eutectic temperature (150–250°C, 3 hours) result in the formation of the tetragonal phase BiIn with a small degree of oxidation. The island morphology is maintained but there is evidence of melting and recrystallization. Transparency is much lower than after laser annealing. RBS and NRA depth profile analysis show that Bi/In films exposed to laser annealing in air contain a large fraction of oxygen and suggest that the converted film may be a BiIn0.6O6 /Bi0.3InO6 bilayer.
Freshwater snails belonging to the genus Biomphalaria are intermediate hosts of the trematode Schistosoma mansoni in the Neotropical region and Africa. In Brazil, one subspecies and ten species of Biomphalaria have been identified: B. glabrata, B. tenagophila, B. straminea, B. occidentalis, B. peregrina, B. kuhniana, B. schrammi, B. amazonica, B. oligoza, B. intermedia and B.t. guaibensis. However, only the first three species are found naturally infected with S. mansoni. The classical identification of these planorbids is based on comparison of morphological characteristics of the shell and male and female reproductive organs, which is greatly complicated by the extensive intra-specific variation. Several molecular techniques have been used in studies on the identification, genetic structure as well as phylogenetic relationships between these groups of organisms. Using the randomly amplified polymorphic DNAs (RAPD) analysis we demonstrated that B. glabrata exhibits a remarkable degree of intra-specific polymorphism. Thus, the genetics of the snail host may be more important to the epidemiology of schistosomiasis than those of the parasite itself. Using the simple sequence repeat anchored polymerase chain reaction (SSR-PCR) in intra-populational and intra-specific studies we have demonstrated that snails belonging to the B. straminea complex (B. straminea, B. kuhniana and B. intermedia) clearly presented higher heterogeneity. Using the low stringency polymerase chain reaction (LS-PCR) technique we were able to separate B. glabrata from B. tenagophila and B. tenagophila from B. occidentalis. To separate all Brazilian Biomphalaria species we used the restriction fragment length polymorphism (PCR-RFLP) of the internal transcribed spacer region (ITS) of the DNA gene. The method also proved to be efficient for the specific identification of DNA extracted from snail eggs. Recently we have sequenced the ITS2 region for phylogenetic studies of all Biomphalaria snails from Brazil.
Guide RNAs (gRNAs) are encoded both in the maxicircle and
minicircle components of the mitochondrial DNA of trypanosomatid
protozoa. These RNAs mediate the precise insertion and deletion
of U residues in transcripts of the maxicircle DNA. We showed
previously that the old UC laboratory strain of Leishmania
tarentolae apparently lost more than 40 minicircle-encoded
gRNAs that are present in the recently isolated LEM125 strain
[Thiemann et al., EMBO J, 1994,
13:5689–5700]. We have further analyzed
the population of minicircle-encoded gRNAs in the LEM125 strain.
Sau3AI and MspI minicircle libraries were
constructed and screened for novel gRNAs by negative colony
hybridization. This search yielded 20 minicircles encoding new
gRNAs that covered most of the remaining gaps in the editing
cascades of the ND8, ND9, G4, and G5 genes, and in addition,
more than 30 minicircles containing either unassigned or
undetectable gRNA genes. We also completely sequenced 34 of
the 45 minicircle sequence classes encoding previously identified
gRNAs. A total of 19 pairs of redundant gRNAs, which are gRNAs
of different sequences covering the same editing blocks, were
identified. The gRNAs in each redundant pair generally had
different relative abundances and different extents of mismatches
with edited sequences. Alignments of the minicircles encoding
redundant gRNAs yielded 59 to 93% matching nucleotides, suggesting
an origin from duplication of ancestral minicircles and subsequent
genetic drift. We propose a functional explanation for the
existence of redundant gRNAs in this strain.
The relatively poor efficiency of phosphor materials in cathodoluminescence with low accelerating voltages is a major concern in the design of field emission flat panel displays operated below 5 kV. Our research on rare-earth-activated phosphors indicates that mechanisms involving interactions of excited activators have a significant impact on phosphor efficiency. Persistence measurements in photoluminescence (PL) and cathodoluminescence (CL) show significant deviations from the sequential relaxation model. This model assumes that higher excited manifolds in an activator de-excite primarily by phonon-mediated sequential relaxation to lower energy manifolds in the same activator ion. In addition to sequential relaxation, there appears to be strong coupling between activators, which results in energy transfer interactions. Some of these interactions negatively impact phosphor efficiency by nonradiatively de-exciting activators. Increasing activator concentration enhances these interactions. The net effect is a significant degradation in phosphor efficiency at useful activator concentrations, which is exaggerated when low–energy electron beams are used to excite the emission.
We report the integration of six levels of Cu interconnects using dual inlaid patterning in a 0.2 μm logic technology. A review of process technology as well as device performance shortcomings using conventional aluminum metallization has been presented. Two tantalum based barriers, TaNx and Ta-Si-N as well as a titanium based barrier, CVD TiN, have been evaluated for their applicability. The use of embedded barriers wherein the barrier is formed below the surface of the dielectric has also been discussed as a potential option. No degradation to the device front-end parametrics were found with the choice of an appropriate barrier. Planarization by Cu CMP introduces surface topography that needs to be minimized in order to process multiple levels of interconnects within specified sheet resistance distributions for a range of line widths. Excellent results with highly planarized levels of metallization have consistently been achieved through an optimization of the unit processes and device integration.
Permanent X(2) gratings can be written in doped silica fibers by coherent irradiation with light at ω and 2ω. The X(2) gratings give rise to phase-matched second harmonic generation (SHG), i.e. subsequent irradiation of the prepared fiber with light at ω results in an output at 2ω. The efficiency with which the gratings can be written depends on the nature and concentration of defect states induced by dopants in the, glass. We present results for fibers doped with Ge and rare earth ions and discuss the implications of our results for the various mechanisms that have been proposed to explain photoinduced SHG in fibers.
The fracture properties of selected commercial composite dental restorative materials and a model composite system were studied to determine the influences of the reinforcing phase, exposure to water, and particle/polymer adhesion on crack propagation. The content of inorganic fillers ranged from 36 to 62 volume percent. In the model system the polymer phase approximated that of the commercial products, a constant size distribution of quartz fillers was used, and polymer/particle adhesion was varied. The double torsion test method was employed to measure relationships between applied stress intensity factor and velocity of crack propagation during stable crack growth. In all systems, cracks propagated through regions of high stress concentration at the low end of the velocity range studied (10−7 m/sec to 10−3 m/sec). Wet materials fractured at lower stress intensities than dry materials at all velocities. At high velocities unstable (stick-slip) growth occurred in dry materials with strong filler/matrix interfaces and in wet specimens with initially strong interfaces and less than 41 volume percent filler. In wet conditions, materials with poorly bonded fillers fractured by slow crack growth at stress intensities 10% to 30% below the levels of composites with strong interfaces.
Cow-calf operations dominate cattle production in the Southeast. The 1978 January 1 U.S. cattle inventory report shows that breeding cows make up 45 percent of the total inventory in Region 41 compared with 33.3 percent nationally . Further, in 1977 cow slaughter accounted for 64.8 percent of federally inspected cattle slaughter in Region 4 compared with 23.6 percent nationally .
Administration, by dietary supplement, of ethylestrenol to rainbow trout and to salmon parr results in significant increases in growth rate; further treatment of smolts retained in fresh water reduces the growth rate. Treated parr develop into 1 + smolts in significantly lower proportion than controls, but have a higher condition factor.
Stress induces in rainbow trout long-lasting reductions in plasma thyroxine levels and increases in serum cortisol concentrations. The origin and significance of these changes is discussed.
The administration of 17β-oestradiol at 20 mg/kg of food for the first 30 days of feeding causes sex-reversal of male salmonids. Treatment with 17α-methyltestosterone at 3 mg/kg food for 90 days following first-feeding causes sex-reversal of female salmonids.
The histology of the spurdog (Squalus acanthias L.) testis was observed through a complete annual cycle. The maximum sperm accumulation coincided with the breeding time as defined by the biennial female cycle. Degeneration of spermatogonia was observed following breeding. The band of degenerate germinal ampullae was identical to that described as occurring in Scyliorhinus canicula (L.) following pituitary ventral lobectomy. This suggested a resting phase in the production of a specific pituitary gonadotrophin lasting for about four months. All spermatocytes were transformed to spermatozoa within 12 months. 3β-Hydroxysteroid dehydrogenase activity was located in semen, in Sertoli cell cytoplasm and in the lumens of mature germinal ampullae. A possible seasonal change in this activity due to the migration of the degenerate band is suggested. Interstitial cells of Leydig could not be observed.
The Scottish-Norwegian stock of the spurdog, Squalus acanthias L., sampled for this study, was shown by Holden (1965) to make an autumn breeding migration from the region of the Orkney and Shetland isles to the breeding areas in the Minch off north-west Scotland. During January and February those females carrying embryos at the end of their second year of development move inshore and liberate their young in shallow water. At this time the ovaries of these fish contain from three to fifteen eggs ready for ovulation (Holden & Meadows, 1964), and observations suggest that copulation, ovulation and the commencement of a further pregnancy follow almost immediately. Following copulation, the spermatozoa must reach the oviducal gland at the head of the oviduct in order that the eggs may be fertilized before they are enclosed by the candle membranes.
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