DISTRIBUTION OF POTASSIUM, CALCIUM, MAGNESIUM, AND SODIUM IN GRASSES AT PROGRESSIVE STAGES OF MATURITY

1964 ◽  
Vol 44 (4) ◽  
pp. 318-324 ◽  
Author(s):  
G. I. Pritchard ◽  
W. J. Pigden ◽  
L. P. Folkins
Keyword(s):  
Low Concentrations ◽  
Calcium Magnesium ◽  
Mg Content

Distribution of potassium (K), calcium (Ca), and magnesium (Mg) in timothy and bromegrass cut at eight progressive dates was similar in both grasses. Highest concentrations were usually found in leaves, lowest at the base of stems, with levels in stems increasing toward the center or tips. With progressive maturity, K, Ca, and Mg content of stems decreased whereas in leaves and heads, K decreased, Ca increased, and Mg remained relatively constant. Sodium (Na) showed little change with progressive cutting dates but low concentrations of this element suggest an inadequate supply in the soil to permit deposition in the plant.In both grasses, ratios of K/Ca, K/Mg, K/(Mg+Ca), were large. These ratios stayed relatively constant in leaves throughout the season but decreased in heads and stems with progressive cuttings. The Ca/Mg ratio tended to be higher in stems than in heads.

Inter-Relationships of Carbonate, Phosphate, Monohydrogen Phosphate, Calcium, Magnesium and Sodium in Uraemic Bone: Comparison of Dialysed and Non-Dialysed Patients

1977 ◽  
Vol 53 (4) ◽  
pp. 307-316
Author(s):  
E. D. Pellegrino ◽  
R. M. Biltz ◽  
J. M. Letteri
Keyword(s):  
Bone Mineral ◽  
Compact Bone ◽  
Octacalcium Phosphate ◽  
Reciprocal Relationship ◽  
Bone Composition ◽  
Low Concentrations ◽  
Fixed Base ◽  
Calcium Magnesium ◽  
High Concentrations ◽  
Phosphate Carbonate

1. Chemical and morphological features of uraemic bone disease were studied by comparison of bone composition in 44 patients with uraemia (12 dialysed and 32 non-dialysed) and 36 control subjects. The significant changes included decreased bone mineral carbonate associated with calcium, a concomitant increase in phosphate, and an increase in magnesium. There was also an increase in osteoid and a reduction in the specific gravity of the compact bone. 2. The most marked changes in bone composition were observed in patients with uraemia of more than 1 year's duration, who had been dialysed. Bone mineral sodium concentrations were not significantly altered in any group. 3. The changes in bone mineral composition appeared to be the result of several simultaneous and/or successive mechanisms: (i) loss of fixed base, calcium carbonate; (ii) replacement of carbonate by phosphate; (iii) the addition of immature bone mineral, which contains high concentrations of phosphate and relatively low concentrations of carbonate. 4. These observations are consistent with earlier views of the bone salt as an indefinite calcium/phosphate/carbonate complex. Variations in bone composition may arise from a reciprocal relationship between phosphate and carbonate. The bone mineral analogue that best explains these variations in bone composition is octacalcium phosphate carbonate [Ca4(PO4)2(HPO4)x(CO3)1-x,zH2O].

Multivariate analysis of geographic covariance between phenotypes and environments in the threespine stickleback, Gasterosteus aculeatus, from the Cook Inlet area, Alaska

1994 ◽  
Vol 72 (8) ◽  
pp. 1497-1509 ◽  
Author(s):  
J. F. Bourgeois ◽  
D. M. Blouw ◽  
J. P. Koenings ◽  
M. A. Bell
Keyword(s):  
Gene Flow ◽  
Environmental Factors ◽  
Lake Water ◽  
Gasterosteus Aculeatus ◽  
Ion Composition ◽  
Cook Inlet ◽  
Lake Productivity ◽  
Low Concentrations ◽  
Calcium Magnesium ◽  
Reactive Phosphorus

Widely distributed freshwater populations of Gasterosteus aculeatus exhibit reduction in the bones of the pelvis and the numbers of lateral plates and dorsal spines. We investigated the relationship between skeletal reduction and the characteristics of the environments in which it occurs. A combination of environmental factors, including environmental ion composition – lake productivity, geographic position, opportunity for gene flow, and the presence of other fishes, is associated with skeletal reduction. The principal correlates of reduction in all skeletal traits are low concentrations of calcium, magnesium, silicon, H+, and reactive phosphorus. We hypothesize that the ion composition of lake water is the main selective agent promoting skeletal reduction in sticklebacks in the Cook Inlet area, Alaska, and that other fishes and local gene flow may modify its extent. Our results show that a suite of skeletal traits responds in common to the interacting effects of at least three environmental factors (ion composition of lake water, presence of other fishes, local gene flow), and they emphasize that unitary explanations of the evolution of skeletal reduction are unlikely to be adequate.

scholarly journals Insights into Sorption–Mineralization Mechanism for Sustainable Granular Composite of MgO-CaO-Al2O3-SiO2-CO2 Based on Nanosized Adsorption Centers and Its Effect on Aqueous Cu(II) Removal

Nanomaterials ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 116
Author(s):  
Alla G. Morozova ◽  
Tatiana M. Lonzinger ◽  
Vadim A. Skotnikov ◽  
Gennady G. Mikhailov ◽  
Yury Kapelyushin ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Ion Exchange ◽  
Defect Formation ◽  
Exchange Reactions ◽  
Reverse Migration ◽  
Low Concentrations ◽  
Calcium Magnesium ◽  
Living Organisms ◽  
Copper Sorption ◽  
Temporary Binder

Although copper is needed for living organisms at low concentrations, it is one of the pollutants that should be monitored along with other heavy metals. A novel and sustainable composite mineralizing sorbent based on MgO-CaO-Al2O3-SiO2-CO2 with nanosized adsorption centers was synthesized using natural calcium–magnesium carbonates and clay aluminosilicates for copper sorption. An organometallic modifier was added as a temporary binder and a source of inovalent ions participating in the reactions of defect formation and activated sintering. The sorbent-mineralizer samples of specified composition and properties showed irreversible sorption of Cu2+ ions by the ion exchange reactions Ca2+ ↔ Cu2+ and Mg2+ ↔ Cu2+. The topochemical reactions of the ion exchange 2OH− → CO32−, 2OH− → SO42− and CO32− → SO42− occurred at the surface with formation of the mixed calcium–copper carbonates and sulfates structurally connected with aluminosilicate matrix. The reverse migration of ions to the environment is blocked by the subsequent mineralization of the newly formed interconnected aluminosilicate and carbonate structures.

scholarly journals Nutrient Uptake and Fruit Quality of Pummelo as Influenced by Ammonium, Potassium, Magnesium, Zinc Application

2015 ◽  
Vol 8 (1) ◽  
pp. 100
Author(s):  
Hien Huu Nguyen ◽  
Somsak Maneepong ◽  
Potjamarn Suranilpong
Keyword(s):  
Nutrient Uptake ◽  
Fruit Quality ◽  
Low Concentrations ◽  
Exchangeable Ca ◽  
High K ◽  
Southern Thailand ◽  
K Fertilizer ◽  
Citrus Maxima ◽  
Calcium Magnesium

<p>Pummelo-growing soils in southern Thailand are usually low concentrations of potassium, calcium, magnesium and zinc; therefore, the roles of these elements are essential and their effects on nutrient uptake and fruit quality that should be considered in this area in current and future pummelo orchard. The study was carried out during 2013 to 2014 production year on a 17 year pummelo (<em>Citrus maxima</em> Merr.). The objective of the study was to examine the effects of ammonium (NH<sub>4</sub>), potassium (K), magnesium (Mg) and zinc (Zn) fertilization over the farmer practice on nutrient uptake and fruit quality. The experiment comprised of 5 treatments; apply all, not apply NH<sub>4</sub>, not apply K, not apply Mg and farmer practice. Application of fertilizer increased N, Ca and Mg concentrations in the leaves, but K and Zn concentrations in leaves decreased after application. However, their concentrations were in optimum ranges. High K/Ca, K/Mg mole ratios and low exchangeable Mg in soil positively affected on K uptake. Low Ca/Mg mole ratio and low exchangeable Ca in soil negatively affected on Ca uptake. The TSS and TSS/TA tended to decline when the treatments were not applied K-fertilizer. The fruit qualities were greater in the treatments with K/Ca, K/Mg and Ca/Mg mole ratios in soil were 0.23 to 0.27, 0.63 to 0.71 and 2.35 to 3.08, respectively. This study showed that K and Zn still required for pummelo growing in this soil.</p>

Spurious hyperkalaemia due to EDTA contamination: common and not always easy to identify

2008 ◽  
Vol 45 (6) ◽  
pp. 601-603 ◽  
Author(s):  
Michael P Cornes ◽  
Clare Ford ◽  
Rousseau Gama
Keyword(s):  
Alkaline Phosphatase ◽  
Acetic Acid ◽  
Prospective Study ◽  
Phosphatase Activity ◽  
Alkaline Phosphatase Activity ◽  
Serum Potassium ◽  
Reference Range ◽  
Serum Zinc ◽  
Low Concentrations ◽  
Calcium Magnesium

Background To study the detection and prevalence of spurious hyperkalaemia due to potassium ethylenediaminetetra-acetic acid (kEDTA) contamination. Methods In a one-month prospective study, serum EDTA, zinc, calcium, magnesium concentrations and alkaline phosphatase activity were measured in samples with serum potassium ≥6.0 mmol/L. Results Twenty-eight out of 117 hyperkalaemic samples were contaminated with EDTA. Only serum zinc values below the reference range had 100% sensitivity for indicating EDTA contamination, but even at an optimal specificity of 89% at least 12 potentially genuine hyperkalaemic samples would be rejected. Conclusion Spurious hyperkalaemia due to kEDTA contamination is common. Gross kEDTA contamination is obvious by marked unexpected hyperkalaemia, hypocalcaemia, hypomagnesaemia and hypozincaemia. Spurious hyperkalaemia due to low concentrations of kEDTA contamination can only be confidently detected by measurement of serum EDTA.

scholarly journals Changes in Mineral Nutrient Concentrations in Petunia Corollas during Development and Senescence

HortScience ◽  
2003 ◽  
Vol 38 (1) ◽  
pp. 71-74 ◽  
Author(s):  
Sven Verlinden
Keyword(s):  
Ethylene Production ◽  
Dry Weight ◽  
Potassium Content ◽  
Mineral Nutrient ◽  
Nutrient Concentrations ◽  
Fresh Weight ◽  
Low Concentrations ◽  
Calcium Magnesium ◽  
Phosphorus And Potassium ◽  
Nitrogen Phosphorus

To observe changes in the nutritional status of corollas during development and senescence, Petunia ×hybrida cv. Mitchell corollas were analyzed for macronutrient and micronutrient content, dry weight, fresh weight, and ethylene production. Carbon content decreased at slightly lower rates than dry weight during corolla development between anthesis and senescence, while fresh weight and ethylene production followed patterns expected of climacteric flowers. Nitrogen, phosphorus, and potassium content declined during development. Both phosphorus and potassium content gradually declined throughout development with overall losses of about 75% and 40%, respectively. Nitrogen content declined 50% during development but losses occurred only during the final stages of senescence. No significant changes were observed in sulfur, calcium, magnesium, and micronutrient content of the corollas during development. Most elements were present in much lower concentrations in corollas than in leaves. The concentrations of calcium, magnesium, and manganese were about 1-, 5-, and 15-fold lower in corollas than in leaves, respectively. Results indicate that remobilization of selected macronutrients from corollas occurred before and during senescence. Taken together with the presence of low concentrations of macronutrients, my data support the contention that petunia corollas are nutritionally in expensive and therefore easily disposable organs.

Highly effective method of human oocyte activation

Zygote ◽  
1995 ◽  
Vol 3 (2) ◽  
pp. 157-161 ◽  
Author(s):  
Jacob Levron ◽  
Jacques Cohen ◽  
Steen Willadsen
Keyword(s):  
Polar Body ◽  
Human Oocyte ◽  
Isotonic Solution ◽  
Oocyte Activation ◽  
Effective Activation ◽  
Low Concentrations ◽  
Activation Efficiency ◽  
Calcium Magnesium ◽  
Second Polar Body ◽  
Activation Rates

SummaryFresh and aged unfertilised human oocytes were activated by electroporation and by exposure to isotonic solution of mannitol supplemented with low concentrations of calcium magnesium and chloride. Over 95% of the fresh oocytes were activated, all showing formation of one pronucleus and extrusion of the second polar body. Oocytes activated 1 and 2 days post-collection showed activation rates of 66.6% and 64.1%, respectively; however, the proportion of one-pronucleate oocytes in these groups was significantly lower (61.6% and 23.5%, respectively). There was no difference in the activation efficiency between the two activation modes. Twelve activated oocytes from the freshly collected group cleaved when left in culture. It is concluded that, in the human, a brief exposure to isotonic solution of mannitol with low concentrations of calcium, magnesium and chloride is a very effective activation stimulus.

Puddles created by geophagous mammals are potential mineral sources for frugivorous bats (Stenodermatinae) in the Peruvian Amazon

2010 ◽  
Vol 26 (2) ◽  
pp. 173-184 ◽  
Author(s):  
Adriana Bravo ◽  
Kyle E. Harms ◽  
Louise H. Emmons
Keyword(s):  
Activity Patterns ◽  
Oxbow Lakes ◽  
Peruvian Amazon ◽  
South Eastern ◽  
Nutrient Limitations ◽  
Large Numbers ◽  
Low Concentrations ◽  
Calcium Magnesium ◽  
Reproductive Females ◽  
The Tropics

Abstract:Natural licks are activity hotspots for frugivorous bats in the Peruvian Amazon. Large numbers of frugivorous bats congregate at licks to drink water. Because most Amazonian soils are relatively poor in nutrients, plants may contain low concentrations of some nutrients; consequently, frugivorous bats may face nutrient limitations. Accordingly, a potential explanation for lick visitation by bats is to obtain key limited resources. We assessed this hypothesis by comparing concentrations of cations (Ca, K, Mg, Na) in water at three licks and associated non-lick sites across years and seasons at Los Amigos Conservation Concession in south-eastern Peru. We also examined bat activity patterns between lick and non-lick sites. Regardless of the season, at licks >10 bats per net h−1 were captured compared with forest and gap sites where <1 bat per net h−1 was captured. At licks bats belonged primarily to the subfamily Stenodermatinae and over 70% were reproductive females. Although calcium, magnesium and potassium concentrations varied across water sources, sodium concentrations were consistently higher in lick water (>50 ppm) compared with creeks and oxbow lakes (<2 ppm) across seasons. Therefore, since sodium is one of the most limiting nutrients for vertebrates in the tropics, licks may function as sources of sodium (or other elements) for bats. In any case, licks are reliable potential sources of sodium in the south-eastern Peruvian Amazon, an otherwise mineral-poor landscape.

Microtubule nucleation sequence studied by time-resolved x-ray scattering and electron microscopy

1983 ◽  
Vol 41 ◽  
pp. 766-767
Author(s):  
Eva-Maria Mandelkow ◽  
Eckhard Mandelkow ◽  
Joan Bordas
Keyword(s):  
Electron Microscopy ◽  
Dynamic Equilibrium ◽  
Time Resolved ◽  
X Ray ◽  
Additional Information ◽  
X Ray Scattering ◽  
Low Concentrations ◽  
Microtubule Growth ◽  
Ray Patterns ◽  
Ray Scattering

When a solution of microtubule protein is changed from non-polymerising to polymerising conditions (e.g. by temperature jump or mixing with GTP) there is a series of structural transitions preceding microtubule growth. These have been detected by time-resolved X-ray scattering using synchrotron radiation, and they may be classified into pre-nucleation and nucleation events. X-ray patterns are good indicators for the average behavior of the particles in solution, but they are difficult to interpret unless additional information on their structure is available. We therefore studied the assembly process by electron microscopy under conditions approaching those of the X-ray experiment. There are two difficulties in the EM approach: One is that the particles important for assembly are usually small and not very regular and therefore tend to be overlooked. Secondly EM specimens require low concentrations which favor disassembly of the particles one wants to observe since there is a dynamic equilibrium between polymers and subunits.

The CM120 Biotwin: a high-contrast objective lens, optimum cryo-vacuum and improved EDX performance

1995 ◽  
Vol 53 ◽  
pp. 584-585
Author(s):  
Uwe Lücken ◽  
Michael Felsmann ◽  
Wim M. Busing ◽  
Frank de Jong
Keyword(s):  
Life Science ◽  
Focal Length ◽  
Objective Lens ◽  
High Contrast ◽  
Contrast Imaging ◽  
X Ray ◽  
Forming Mechanism ◽  
Similar Image ◽  
High Contrast Imaging ◽  
Low Concentrations

A new microscope for the study of life science specimen has been developed. Special attention has been given to the problems of unstained samples, cryo-specimens and x-ray analysis at low concentrations.A new objective lens with a Cs of 6.2 mm and a focal length of 5.9 mm for high-contrast imaging has been developed. The contrast of a TWIN lens (f = 2.8 mm, Cs = 2 mm) and the BioTWTN are compared at the level of mean and SD of slow scan CCD images. Figure 1a shows 500 +/- 150 and Fig. 1b only 500 +/- 40 counts/pixel. The contrast-forming mechanism for amplitude contrast is dependent on the wavelength, the objective aperture and the focal length. For similar image conditions (same voltage, same objective aperture) the BioTWIN shows more than double the contrast of the TWIN lens. For phasecontrast specimens (like thin frozen-hydrated films) the contrast at Scherzer focus is approximately proportional to the √ Cs.

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