Metabolism of arginine, proline, and ornithine in tissues of the squid, Illex illecebrosus

1983 ◽  
Vol 61 (8) ◽  
pp. 1835-1846 ◽  
Author(s):  
Thomas P. Mommsen ◽  
Peter W. Hochachka ◽  
Christopher J. French
Keyword(s):  
Digestive Gland ◽  
Main Product ◽  
Arginine Metabolism ◽  
Low Concentrations ◽  
Tissue Homogenates

Interconversions of arginine, ornithine, and proline were studied in the squid Illex illecebrosus, by supplying tissue homogenates from kidney, digestive gland, heart, brain, gill, middle and outer mantle with 14C-labelled substrates. Production of 14CO2 and distribution of label in various intermediates were measured for each tissue. Activities of enzymes catalysing the interconversions were also assessed. 14CO2 production was highest in middle and outer mantle with arginine as substrate, in kidney with ornithine, and in heart with proline. Urease was absent from all tissues. All tissues utilised arginine at reasonable rates, the highest being observed in middle and outer mantle and digestive gland. In heart, γ-guanidinobutyrate was the main product of arginine metabolism. In all other tissues, ornithine was the first product. Kidney utilised ornithine at the fastest rate, while proline was utilised and oxidised best by heart and brain. The results suggest that the capacity of all tissues to metabolise arginine rapidly is a means for maintaining low concentrations of this compound. In some tissues (brain, kidney) the products of arginine metabolism may be fully oxidised in situ whereas in others (digestive gland, gill) produced ornithine may be exported for utilisation elsewhere.

scholarly journals Microwave Sensors for In Situ Monitoring of Trace Metals in Polluted Water

Sensors ◽  
2021 ◽  
Vol 21 (9) ◽  
pp. 3147
Author(s):  
Ilaria Frau ◽  
Stephen Wylie ◽  
Patrick Byrne ◽  
Patrizia Onnis ◽  
Jeff Cullen ◽  
...  
Keyword(s):  
Trace Metals ◽  
In Situ Monitoring ◽  
Polluted Water ◽  
Pollution Level ◽  
Mining Areas ◽  
Low Concentrations ◽  
The Uk ◽  
Microwave Sensors ◽  
Immediate Response

Thousands of pollutants are threatening our water supply, putting at risk human and environmental health. Between them, trace metals are of significant concern, due to their high toxicity at low concentrations. Abandoned mining areas are globally one of the major sources of toxic metals. Nowadays, no method can guarantee an immediate response for quantifying these pollutants. In this work, a novel technique based on microwave spectroscopy and planar sensors for in situ real-time monitoring of water quality is described. The sensors were developed to directly probe water samples, and in situ trial measurements were performed in freshwater in four polluted mining areas in the UK. Planar microwave sensors were able detect the water pollution level with an immediate response specifically depicted at three resonant peaks in the GHz range. To the authors’ best knowledge, this is the first time that planar microwave sensors were tested in situ, demonstrating the ability to use this method for classifying more and less polluted water using a multiple-peak approach.

Comparison of the Effect of Boron and Phosphorus Impurities on Solid Phase Epitaxial Regrowth of Amorphous Silicon

1989 ◽  
Vol 157 ◽  
Author(s):  
Young-Jin Jeon ◽  
M.F. Becker ◽  
R.M. Walser
Keyword(s):  
Amorphous Silicon ◽  
Isothermal Annealing ◽  
Solid Phase ◽  
Laser Interferometry ◽  
Electron Pairs ◽  
Quadratic Equations ◽  
Low Concentrations ◽  
Fractional Ionization ◽  
Reported Data

ABSTRACTThis work was concerned with comparing the relative effects of boron and phosphorus impurities on the solid phase epitaxial (SPE) regrowth rate of self-ion amorphized layers in silicon wafers with (100) orientation. We used previously reported data measured by in situ, high precision, cw laser interferometry during isothermal annealing for temperatures from 450°C to 590°C, and concentrations in the range from 7.8×1018 cm-3 to 5×l020 cm-3 for boron (NB), and from 5×l017 cm-3 to 3×1020 cm-3 for phosphorus (Np) impurities. The basis for the comparison was a recently developed model that extends the Spaepen-Turnbull model for silicon recrystallization to include ionization enhanced processes.The experimental data for bom boron and phosphorus exhibited the linear variation in regrowth rate expected for low concentrations of implanted hydrogenic impurities having a concentration-independent fractional ionization in amorphous silicon. In the linear range the relative enhanced regrowth rate produced by these impurities can be expressed as a product of their, relative fractional ionizations, and the relative amount the rate constant for reconstruction is altered by localizing an electron, or a hole, at the reconstruction site. Assuming that a localized hole and electron equally softened the potential barrier for reconstruction, the experimental results indicated that boron had an ?40 meV lower barrier to ionization in amorphous silicon than phosphorus.The variations in the SPE regrowth rates with higher concentrations of both implanted boron and phosphorus were well fit by quadratic equations, but with different curvatures (+ and - for B and P respectively). This result was interpreted to indicate that SPE regrowth was further enhanced by localized hole pairs, but retarded by localized electron pairs.

On the dimorphism of Pr6Mo10O39

2017 ◽  
Vol 72 (11) ◽  
pp. 765-774
Author(s):  
Daniel Rudolph ◽  
Sonja Laufer ◽  
Ingo Hartenbach
Keyword(s):  
Crystal Structure ◽  
Thermal Decomposition ◽  
Single Crystals ◽  
Main Product ◽  
Molar Ratio ◽  
Coordination Environment ◽  
Space Group ◽  
Coordination Numbers ◽  
Dense Modification

AbstractAttempts to synthesize Pr4Mo7O27 using Pr, Pr6O11 and MoO3 in a molar ratio of 8:6:77 led to a main product of scheelite-type Pr0.667[MoO4] and few single crystals of the triclinic A-type Pr6Mo10O39. The latter crystallizes in space group P1̅ (a=945.25(1), b=1058.49(2), c=1815.16(3) pm; α=104.149(1), β=95.220(1), γ=102.617(1)°, Z=2). Its crystal structure comprises six crystallographically independent Pr3+ cations, eight tetrahedral [MoO4]2− units, and one [Mo2O7]2− entity. The cations display coordination numbers of seven (1×) and eight (5×), while the [MoO4]2− tetrahedra are surrounded by five Pr3+ cations each. The [Mo2O7]2− anions exhibit a coordination environment of seven Pr3+ cations. The attempt to synthesize PrF[MoO4] using PrOF (from in situ thermal decomposition of PrF[CO3]) as reagent did not lead to the desired product but to monoclinic B-type Pr6Mo10O39. This slightly less dense modification compared to its triclinic analogue crystallizes in space group C2/c (a=1247.93(3), b=1989.68(6), c=1392.52 (4) pm, β=100.505(2)°, Z=4) with three crystallographically independent Pr3+ cations, four [MoO4]2− tetrahedra, and again one [Mo2O7]2− unit in the crystal structure. Thus, both Pr6Mo10O39 modifications are better described with the structured formula Pr6[MoO4]8[Mo2O7]. The coordination numbers around the Pr3+ cations are seven (1×) and eight (2×) while all four [MoO4]2− anions are again surrounded by five Pr3+ cations each. Six of the latter represent the coordination environment around the [Mo2O7]2− entities. Besides the thorough comparison of the crystal structures single crystal Raman spectra were recorded for both Pr6Mo10O39 phases.

scholarly journals The effect of pregnancy on the expression of uterine oxytocin, oestrogen and progesterone receptors during early pregnancy in the cow

1999 ◽  
Vol 160 (1) ◽  
pp. 21-33 ◽  
Author(s):  
RS Robinson ◽  
GE Mann ◽  
GE Lamming ◽  
DC Wathes
Keyword(s):  
Cross Sections ◽  
Early Pregnancy ◽  
In Situ Hybridisation ◽  
Progesterone Receptors ◽  
Prostaglandin F2alpha ◽  
Interferon Tau ◽  
Uterine Endometrium ◽  
Low Concentrations ◽  
Oxytocin Antagonist

The expression of oxytocin receptor (OTR) in the uterine endometrium plays an important role in the initiation of luteolysis. During early pregnancy, the conceptus secretes interferon tau (IFN|gt) which inhibits OTR up-regulation and luteolysis. In this study, uterine horn cross sections were collected on day 16 from 15 pregnant cows (PREG), 9 uninseminated controls and 5 inseminated cows with no embryo present. The latter two groups had similar results and were combined to form a single non-pregnant (NP) group. The animals were given an oxytocin challenge shortly before tissue collection to assess prostaglandin F2alpha (PGF2alpha) release through the measurement of the metabolite 13,14-dihydro-15-keto PGF2alpha (PGFM). The mRNAs for OTR, oestrogen receptor (ER) and progesterone receptor (PR) were localised by in situ hybridisation. The results were quantified by optical density (OD) measurements from autoradiographs using image analysis. OTR protein was measured by autoradiography with iodinated oxytocin antagonist and ER and PR protein was detected by immunocytochemistry. The release of PGFM after the oxytocin challenge was significantly higher in the 14 NP cows (187%+/-15%) compared with the PREG group (131%+/-11%) (P<0.01). Low concentrations of OTR mRNA were localised to the luminal epithelium (LE) in 6 out of the 14 NP cows, of which 2 also expressed OTR protein, while OTR mRNA and protein were undetectable in all the pregnant animals. These results indicated that the sampling time coincided with the onset of the luteolytic mechanism in the NP cows. On day 16 ER mRNA was detectable in both the LE and glands of both PREG and NP animals. There were no differences in either ER mRNA or protein between NP and PREG samples. PR mRNA was moderately expressed in the caruncular stroma, with lower levels in the dense caruncular-like stroma and glands. There were no differences between PREG and NP animals. The expression of PR mRNA and protein in the deep glands was variable between animals. These results suggested that, in cows, the presence of an embryo suppressed the expression of OTR, but had no effect on the expression of the transcriptionally regulated ER on day 16.

scholarly journals Corrosion in CO2 Systems with Impurities Creating Strong Acids

CORROSION ◽  
10.5006/3110 ◽  
2019 ◽  
Vol 75 (11) ◽  
pp. 1307-1314
Author(s):  
Bjørn H. Morland ◽  
Morten Tjelta ◽  
Arne Dugstad ◽  
Gaute Svenningsen
Keyword(s):  
Sulfuric Acid ◽  
Carbon Steel ◽  
Stainless Steels ◽  
Elemental Sulfur ◽  
Experimental Studies ◽  
Visual Observation ◽  
Low Concentrations ◽  
Strong Acids ◽  
Safety And Environment

There are several proposed specifications for CO2 transport regarding how much impurities that can be allowed in the CO2 stream. Many of these specifications are based on health, safety, and environment (HSE) considerations in case of accidental spill, and only limited focus has been on the pipeline integrity. Previous work has demonstrated that many of the impurities that are expected to be present in CO2 captured from flue gasses may react and form corrosive species. The present paper studied impurity reactions and corrosion under simulated transport conditions (25°C and 10 MPa of CO2). An experiment was performed in a transparent autoclave which allowed for in situ visual observation. Chemical reactions between the impurities were observed even at very low concentrations (<100 ppmv). These reactions contributed to the production of nitric and sulfuric acid together with formation of elemental sulfur. Corrosion was observed on coupons of carbon steel, but not on stainless steels. The corrosion rate of carbon steel was low, but the amount of acids and solids (corrosion products) produced cannot be accepted from a pipeline integrity perspective. Further experimental studies are needed to determine specific limits for impurity concentrations in captured CO2 for transport.

scholarly journals Cadmium Sulfide Thin Films Deposited onto MWCNT/Polysulfone Substrates by Chemical Bath Deposition

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
M. Moreno ◽  
G. M. Alonzo-Medina ◽  
A. I. Oliva ◽  
A. I. Oliva-Avilés
Keyword(s):  
Thin Films ◽  
Electric Field ◽  
Cadmium Sulfide ◽  
Chemical Bath Deposition ◽  
Multiwall Carbon Nanotubes ◽  
Low Concentrations ◽  
Average Grain Size ◽  
Cds Thin Films ◽  
Current Electric Field

Cadmium sulfide (CdS) thin films were deposited by chemical bath deposition (CBD) onto polymeric composites with electric field-aligned multiwall carbon nanotubes (MWCNTs). MWCNT/polysulfone composites were prepared by dispersing low concentrations of MWCNTs within dissolved polysulfone (PSF). An alternating current electric field was “in situ” applied to align the MWCNTs within the dissolved polymer along the field direction until the solvent was evaporated. 80 μm thick solid MWCNT/PSF composites with an electrical conductivity 13 orders of magnitude higher than the conductivity of the neat PSF were obtained. The MWCNT/PSF composites were subsequently used as flexible substrates for the deposition of CdS thin films by CBD. Transparent and adherent CdS thin films with an average thickness of 475 nm were obtained. The values of the energy band gap, average grain size, rms roughness, crystalline structure, and preferential orientation of the CdS films deposited onto the polymeric substrate were very similar to the corresponding values of the CdS deposited onto glass (conventional substrate). These results show that the MWCNT/PSF composites with electric field-tailored MWCNTs represent a suitable option to be used as flexible conducting substrate for CdS thin films, which represents an important step towards the developing of flexible systems for photovoltaic applications.

scholarly journals Anti-Inflammation of Natural Components from Medicinal Plants at Low Concentrations in Brain via Inhibiting Neutrophil Infiltration after Stroke

2016 ◽  
Vol 2016 ◽  
pp. 1-12 ◽  
Author(s):  
Jiannan Chen ◽  
Xiangjian Zhang ◽  
Cong Zhang ◽  
Wenhui Wang ◽  
Rong Chen ◽  
...  
Keyword(s):  
Medicinal Plants ◽  
Circulatory System ◽  
Neutrophil Infiltration ◽  
Neurological Deficits ◽  
Low Concentrations ◽  
Cerebral Parenchyma ◽  
Natural Components ◽  
Anti Inflammatory ◽  
The Brain

Inflammation after stroke consists of activation of microglia/astrocytesin situand infiltration of blood-borne leukocytes, resulting in brain damage and neurological deficits. Mounting data demonstrated that most natural components from medicinal plants had anti-inflammatory effects after ischemic stroke through inhibiting activation of resident microglia/astrocytes within ischemic area. However, it is speculated that this classical activity cannot account for the anti-inflammatory function of these natural components in the cerebral parenchyma, where they are detected at very low concentrations due to their poor membrane permeability and slight leakage of BBB. Could these drugs exert anti-inflammatory effects peripherally without being delivered across the BBB? Factually, ameliorating blood-borne neutrophil recruitment in peripheral circulatory system has been proved to reduce ischemic damage and improve outcomes. Thus, it is concluded that if drugs could achieve effective concentrations in the cerebral parenchyma, they can function via crippling resident microglia/astrocytes activation and inhibiting neutrophil infiltration, whereas the latter will be dominating when these drugs localize in the brain at a low concentration. In this review, the availability of some natural components crossing the BBB in stroke will be discussed, and how these drugs lead to improvements in stroke through inhibition of neutrophil rolling, adhesion, and transmigration will be illustrated.

A MAS NMR and DRIFT study of the Ga species in Ga/H-ZSM5 catalysts and their effect on propane ammoxidation

2005 ◽  
Vol 83 (6-7) ◽  
pp. 574-580 ◽  
Author(s):  
Prem Pal ◽  
Juliette Quartararo ◽  
Sharifah B Abd Hamid ◽  
Eric G Derouane ◽  
Jacques C Védrine ◽  
...  
Keyword(s):  
Main Product ◽  
External Surface ◽  
Catalytic Performance ◽  
Mas Nmr ◽  
Propane Ammoxidation ◽  
Bifunctional Mechanism ◽  
Propane Activation ◽  
Cationic Exchange ◽  
Zeolite Crystals

71Ga, 27Al, and 29Si MAS NMR and DRIFT spectroscopies were used to characterize the state of gallium in Ga/H-ZSM5 catalysts tested for their ability to catalyse the ammoxidation of propane. Ga species were observed in two different possible environments: octahedrally coordinated gallium in small Ga2O3 particles at the external surface of the zeolite crystals, octahedrally coordinated gallium in GaO(OH) or related species, and tetrahedrally coordinated gallium in cationic-exchange positions inside the zeolite. Redox (H2–O2) cycles promote the migration of gallium from the GaO(OH) or Ga2O3 species at the external surface of the zeolite crystals to cationic-exchange sites within the zeolite channels. The redox treatment definitely had a beneficial effect on its catalytic performance for the ammoxidation of propane, which is known to occur via a bifunctional mechanism. The main product was acetonitrile at high Ga and Al contents while acrylonitrile was also observed as a side product at high Ga and low Al contents.Key words: ZSM5, MFI, in situ studies, MAS NMR, DRIFT, propane activation, ammoxidation.

scholarly journals Colorimetric Analysis with N,N-Dimethyl-p-phenylenediamine of the Uptake of Intravenously Injected Horseradish Peroxidase by Various Tissues of the Rat

1958 ◽  
Vol 4 (5) ◽  
pp. 541-550 ◽  
Author(s):  
Werner Straus
Keyword(s):  
Horseradish Peroxidase ◽  
Blood Serum ◽  
Nerve Tissue ◽  
Colorimetric Determination ◽  
Low Concentrations ◽  
Tissue Homogenates ◽  
Average Activity ◽  
High Concentrations ◽  
Kidney Liver ◽  
Serum And Urine

1. A method is described for the colorimetric determination of peroxidase with N,N-dimethyl-p-phenylenediamine. The amount of red pigment formed by peroxidase is proportional to the concentration of enzyme and to the time of incubation during the first 40 to 90 seconds. The influence of the concentration of enzyme, N,N-dimethyl-p-phenylenediamine, H2O2, the time of incubation, pH, the temperature, and the possible interference by oxidizing and reducing agents of tissues has been tested. 2. The method has been used to follow the uptake of intravenously injected horseradish peroxidase by 18 different tissues of the rat over a period of 30 hours. The highest concentration of the injected tracer enzyme was found in extracts of kidney, liver, bone marrow, thymus, and spleen. Considerable amounts were taken up by pancreas, prostate, epididymis, and small intestine. Lower concentrations were found in extracts of lung, stomach, heart, and skeletal muscle, aorta, skin, and connective tissue. No uptake was observed by brain and peripheral nerve tissue. 3. Tissue homogenates containing high concentrations of the injected peroxidase, in general also showed high or average activity of acid phosphatase. 4. Six hours after intravenous administration, the liver contained 27 per cent, the kidney 12 per cent, and the spleen, 1.4 per cent of the injected dose. 5. Approximately 20 per cent of the injected peroxidase was excreted in the urine during the first 6 hours, and the concentration of peroxidase in blood serum and urine fell exponentially during this time. After 6 hours, only low concentrations were excreted in the urine but low enzyme activity was still detectable after 30 hours. Approximately 6 per cent of the injected dose was excreted in the feces from 6 to 20 hours after administration. 6. After feeding through a stomach tube, low concentrations of peroxidase were found in blood serum and urine. Considerable variations in the extent of absorption from the gastrointestinal tract were observed in individual rats.

Whole-Cell Immunolocalization of Nitrogenase in Marine Diazotrophic Cyanobacteria, Trichodesmiumspp.

1998 ◽  
Vol 64 (8) ◽  
pp. 3052-3058 ◽  
Author(s):  
Senjie Lin ◽  
Sheri Henze ◽  
Pernilla Lundgren ◽  
Birgitta Bergman ◽  
Edward J. Carpenter
Keyword(s):  
Photosynthetic Activity ◽  
Protein Localization ◽  
Distribution Patterns ◽  
Dark Cycle ◽  
Fixation Rate ◽  
Low Concentrations ◽  
If Technique ◽  
Dimethyl Urea ◽  
Diazotrophic Cyanobacteria

ABSTRACT The mechanism by which planktonic marine cyanobacteria of the genusTrichodesmium fix N2 aerobically during photosynthesis without heterocysts is unknown. As an aid in understanding how these species protect nitrogenase, we have developed an immunofluorescence technique coupled to light microscopy (IF-LM) with which intact cyanobacteria can be immunolabeled and the distribution patterns of nitrogenase and other proteins can be described and semiquantified. Chilled ethanol was used to fix the cells, which were subsequently made permeable to antibodies by using dimethyl sulfoxide. Use of this technique demonstrated that about 3 to 20 cells (mean ± standard deviation, 9 ± 4) consecutively arranged in a Trichodesmium trichome were labeled with the nitrogenase antibody. The nitrogenase-containing cells were distributed more frequently around the center of the trichome and were rarely found at the ends. On average 15% of over 300 randomly encountered cells examined contained nitrogenase. The percentage of nitrogenase-containing cells (nitrogenase index [NI]) in an exponential culture was higher early in the light period than during the rest of the light-dark cycle, while that for a stationary culture was somewhat constant at a lower level throughout the light-dark cycle. The NI was not affected by treatment of the cultures with the photosynthetic inhibitor dichloro 1,3′-dimethyl urea or with low concentrations of ammonium (NH4Cl). However, incubation of cultures with 0.5 μM NH4Cl over 2 days reduced the NI. The IF technique combined with 14C autoradiography showed that the CO2 fixation rate was lower in nitrogenase-containing cells. The results of the present study suggest that (i) the IF-LM technique may be a useful tool for in situ protein localization in cyanobacteria, (ii) cell differentiation occurs inTrichodesmium and only a small fraction of cells in a colony have the potential to fix nitrogen, (iii) the photosynthetic activity (CO2 uptake) is reduced if not absent in N2-fixing cells, and (iv) variation in the NI may be a modulator of nitrogen-fixing activity.

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