scholarly journals Gas Secretion in Fishes Lacking Rete Mirabile

1958 ◽  
Vol 35 (3) ◽  
pp. 671-676 ◽  
Author(s):  
G. SUNDNES ◽  
T. ENNS ◽  
P. F. SCHOLANDER
Keyword(s):  
Diffusion Process ◽  
Active Transport ◽  
Pressure Effect ◽  
Current System ◽  
The Other ◽  
Salmonid Fishes ◽  
Rete Mirabile ◽  
Oxygen Capacity ◽  
One Step ◽  
Counter Current

1. Gas secretion has been studied in three species of salmonid fishes, one of which accumulates both nitrogen and oxygen against considerable gradients, while the other two accumulate only nitrogen. None of these three species possesses a counter-current system (rete mirabile) which could step up a slight primary pressure effect. 2. Neither the nitrogen nor the oxygen capacity of the blood is large enough to account for the tensions found in the swimbladder by a simple one-step diffusion process. 3. One is forced therefore to consider a mechanism for active transport of these gases by the cells lining the swimbladder.

scholarly journals The Active Transport of Oxygen and Carbon Dioxide into the Swim-Bladder of Fish

1966 ◽  
Vol 49 (6) ◽  
pp. 1209-1220 ◽  
Author(s):  
H.J. KUHN ◽  
E. MARTI
Keyword(s):  
Carbon Dioxide ◽  
Lactic Acid ◽  
Active Transport ◽  
Bladder Pressure ◽  
Swim Bladder ◽  
Rete Mirabile ◽  
Partial Pressures ◽  
Gas Gland ◽  
Counter Current ◽  
Good Agreement

The active transport of oxygen and carbon dioxide into the swim-bladder of fish is discussed. The rete mirabile is a capillary network which is involved in the gas secretion into the bladder. The rete is regarded as a counter-current multiplier. Lactic acid which is produced in the gas gland generates in the rete single concentrating effects for oxygen and carbon dioxide; i.e., for equal partial pressures the concentrations of the gases in the afferent rete capillaries are higher than those in the efferent ones. The single concentrating effects were calculated from measurements of sea robin blood (Root, 1931). The multiplication of these effects within the rete for different rete lengths and different transport rates was numerically evaluated. The calculated O2 and CO2 pressures in the bladder are in good agreement with the experimental results of Scholander and van Dam (1953). The descent velocities at equilibrium between bladder pressure and hydrostatic pressure are discussed for fishes with different rete lengths.

Introductory remarks

1971 ◽  
Vol 262 (842) ◽  
pp. 85-90 ◽  
Keyword(s):  
Active Transport ◽  
Bulk Flow ◽  
The Other ◽  
Solvent Drag ◽  
Counter Current

It is a generally accepted viewpoint that the processes underlying active transport in tissues are basically the same as those which are operative in individual cells. However, the organization of cells to form epithelia seems to endow them with new potentialities with respect to apparently active transport of solutes and water not usually recognized in individual cells. The new potentialities probably can be traced back to two main sources: (1) that the cells in an epithelium are polarized so that the ‘inward’ and ‘outward’ facing membranes have different properties, and (2) the presence of a system of interspaces which is usually more or less closed towards one side of the epithelium and more open toward the other. In principle the interspace system allows relatively rapid bulk flow which in turn may give rise to ‘solvent drag’, ‘anomalous solvent drag’, and in specialized structures even to counter-current interactions between different streams.

One-step Separation and Purification of Four Phenolic Acids from Stenoloma chusanum (L.) Ching by Medium-pressure Liquid Chromatography and High-speed Counter-current Chromatography

2019 ◽  
Vol 9 (2) ◽  
pp. 138-143
Author(s):  
Tianyun Li ◽  
Xiling Dai ◽  
Yichen Li ◽  
Guozheng Huang ◽  
Jianguo Cao
Keyword(s):  
Natural Products ◽  
Liquid Chromatography ◽  
Phenolic Acids ◽  
High Speed ◽  
High Efficiency ◽  
Total Phenolic ◽  
Medium Pressure ◽  
Medium Pressure Liquid Chromatography ◽  
One Step ◽  
Counter Current

Background:Stenoloma chusanum (L.) Ching is a Chinese traditional medicinal fern with high total flavonoid and total phenolic content. Traditionally, phenolic compounds were separated by using column chromatography, which is relatively inefficient. </P><P> Objective: This study aims to use an efficient method to separate natural products from S. chusanum by Medium-Pressure Liquid Chromatography (MPLC) and High-Speed Counter-Current Chromatography (HSCCC).Methods:In the present research, firstly, a sample (2.5 g) from the dichloromethane extract of S. chusanum was separated by MPLC. Next, fraction P5 was purified by HSCCC with a two-phase solvent system composed of hexane-ethyl acetate-methanol-water (HEMWat) at a volume ratio of 2:4:1:4 (v/v/v/v). </P><P> Result: Four phenolic acids were obtained and their structures were identified by means of NMR and ESI-mass analysis. They were identified as: 1) protocatechuic acid (34 mg, purity 90.1%), 2) syringic acid (66 mg, purity 99.0%), 3) p-hydroxybenzoic acid (5 mg, purity 91.2%) and 4) vanillic acid (6 mg, purity 99.3%).Conclusion:The combination of MPLC and HSCCC is a high-efficiency separation method for natural products. This is the first report with regard to the separation of four phenolic acids in one step by MPLC and HSCCC from S. chusanum (L.) Ching.

Interrelationship of Jatharagni and Dhatvagni in context to Dhatvagni Pradoshaj Vikaras.

2017 ◽  
Vol 2 (1) ◽  
Author(s):  
Kishor G. Satani ◽  
Hemang Raghvani ◽  
Kunjal Bhatt
Keyword(s):  
Basic Concept ◽  
Functional Relationship ◽  
Structural Relationship ◽  
The Other ◽  
Proper Function ◽  
One Step ◽  
Material Form

The concept of Agni is basic concept of Ayurveda. Agni is believed to be the agency for any kind of transformation. Maharshi Vagbhatta says that each of the Dosha, Dhatu, Mala etc. have their own Agni. This is how the number of Agni cannot be limited. Though each and every Agni has its own importance, Dehagni or Jatharagni is the most important one as all other Agnis are depended upon Dehagni. Acharya Vagbhatta says that proper function of every Dhatvagni is depended on the Jatharagni. Increase or decrease of Jatharagni directly affects the function of Dhatvagni. Thus, Maharshi Charaka established functional relationship among Jatharagni and other Agnis. Maharshi Vagbhattta goes one step ahead of Maharshi Charaka by using word “Amsha” means; moieties of Kayagni, located to in its own place, are distributed to and permeate to all the Dhatus. A decrease of it (below the normal) makes for an increase of the Dhatus, while an increase of it (above the normal) makes for a decrease of a Dhatus. This shows structural relationship too, between Jatharagni and Dhatvagni as “Amsha” always indicates Murtatva or material form. Further more all these Agnis are connected with each other and due to this relationship, vitiation of Jatharagni results in vitiation of all the other Agnis.

Controllable Electrochemical Synthesis of Ag Hierarchical Micro/Nanostructures with High SERS-Activity

NANO ◽  
2020 ◽  
Vol 15 (04) ◽  
pp. 2050043
Author(s):  
Huayu Zhou ◽  
Jingjing Wang ◽  
Qiong Yang ◽  
Menglei Chen ◽  
Changsheng Song ◽  
...  
Keyword(s):  
Indium Tin Oxide ◽  
Current System ◽  
Three Dimensional ◽  
Constant Current ◽  
Localized Surface Plasmon ◽  
Excitation Wavelength ◽  
Raman Signal ◽  
Mixed Solution ◽  
Raman Enhancement ◽  
One Step

We report a one-step electrochemical deposition technique to prepare three-dimensional (3D) Ag hierarchical micro/nanostructured film consisting of well-crystallized Ag nanosheets grown on an indium tin oxide (ITO) conductive substrate. The Ag hierarchical micro/nanostructures were fabricated in the mixed solution of AgNO3 and sodium citrate in a constant current system at room temperature. Through reduction of Ag[Formula: see text] electrodeposited on the surface of ITO substrate, nanoparticles were grown to form nanosheets which further combined into 3D sphere-like microstructures. The 3D Ag micro/nanostructures have many sharp edges and nanoscale gaps which can give rise to good Raman-enhanced effect. Due to localized surface plasmon resonance (LSPR) effects, these special Ag micro/nanostructures exhibited good Raman-enhanced performance. Using Rhodamine 6G (R6G) molecules as probe molecule, we studied the influence of excitation wavelength on Raman enhancement. The results showed that the 532[Formula: see text]nm excitation wavelength is the best to obtain the strongest Raman signal and to reduce the influence of other impurity peaks. Using the as-synthesized Ag hierarchical micro/nanostructures, we can detect the 10[Formula: see text][Formula: see text]mol/L R6G aqueous solution, exhibiting great Raman-enhanced effect.

scholarly journals MITOTIC CROSSING OVER AND NONDISJUNCTION IN TRANSLOCATION HETEROZYGOTES OF ASPERGILLUS

Genetics ◽  
1976 ◽  
Vol 82 (4) ◽  
pp. 605-627
Author(s):  
Etta Käfer
Keyword(s):  
Selective Advantage ◽  
The Other ◽  
Translocation Chromosome ◽  
Crossing Over ◽  
Selective Marker ◽  
Reciprocal Translocations ◽  
Poor Growth ◽  
Different Types ◽  
Diploid Genotype ◽  
One Step

ABSTRACT To analyze mitotic recombination in translocation heterozygotes of A. nidulans two sets of well-marked diploids were constructed, homo- or heterozygous for the reciprocal translocations T1(IL;VIIR) or T2(IL;VIIIR) and heterozygous for selective markers on IL. It was found that from all translocation heterozygotes some of the expected mitotic crossover types could be selected. Such crossovers are monosomic for one translocated segment and trisomic for the other and recovery depends on the relative viabilities of these unbalanced types. The obtained segregants show characteristically reduced growth rates and conidiation dependent on sizes and types of mono- and trisomic segments, and all spontaneously produce normal diploid sectors. Such secondary diploid types either arose in one step of compensating crossing over in the other involved arm, or—more conspicuously—in two steps of nondisjunction via a trisomic intermediate.—In both of the analyzed translocations the segments translocated to IL were extremely long, while those translocated from IL were relatively short. The break in I for T1(I;VII) was located distal to the main selective marker in IL, while that of T2(I;VIII) had been mapped proximal but closely linked to it. Therefore, as expected, the selected primary crossover from the two diploids with T2(I;VIII) in coupling or in repulsion to the selective marker, showed the same chromosomal imbalance and poor growth. These could however be distinguished visually because they spontaneously produced different trisomic intermediates in the next step, in accordance with the different arrangement of the aneuploid segments. On the other hand, from diploids heterozygous for T1(I;VII) mitotic crossovers could only be selected when the selective markers were in coupling with the translocation; these crossovers were relatively well-growing and produced frequent secondary segregants of the expected trisomic, 2n+VII, type. For both translocations it was impossible to recover the reciprocal crossover types (which would be trisomic for the distal segments of I and monosomic for most of groups VII or VIII) presumably because these were too inviable to form conidia.—In addition to the selected segregants of expected types a variety of unexpected ones were isolated. The conditions of selection used favour visual detection of aneuploid types, even if these produce only a few conidial heads and are not at a selective advantage. For T2(I;VIII) these "non-selected" unbalanced segregants were mainly "reciprocal" crossovers of the same phenotype and imbalance as the selected ones. For T1(I;VII) two quite different types were obtained, both possibly originating with loss of the small VII-Itranslocation chromosome. One was isolated when the selective marker in repulsion to T1(I;VII) was used and, without being homo- or hemizygous for the selective marker, it produced stable sectors homozygous for this marker. The other was obtained from both coupling and repulsion diploids and showed a near-diploid genotype; it produced practically only haploid stable sectors of the type expected from monosomics, 2n-1 for the short translocation chromosome.

One-step Separation of Three Flavonoids from Poacynum hendersonii by High-speed Counter-current Chromatography

2011 ◽  
Vol 22 (5) ◽  
pp. 450-454 ◽  
Author(s):  
Junyou Shi ◽  
Guoliang Li ◽  
Honglun Wang ◽  
Jie Zheng ◽  
Yourui Suo ◽  
...  
Keyword(s):  
High Speed ◽  
One Step ◽  
Counter Current

Studies on One-Step Preparation of Multi-Color Fluorescent Carbon-Doped Silica Biological Nanomaterials

2013 ◽  
Vol 340 ◽  
pp. 362-365
Author(s):  
Wei Wei Xiong ◽  
Jing Guo ◽  
Xi Chen ◽  
Cheng Yi Zhang
Keyword(s):  
Preparation Method ◽  
The Other ◽  
Fluorescent Substance ◽  
Carbon Doped ◽  
Fluorescence Characteristics ◽  
One Step ◽  
Fluorescent Carbon

The research concentrates on the preparation of the Nontoxic multi-color fluorescent substance. Fluorescent substance in biology exists two major shortcomings, one is that they are toxic and the other is that they are relatively monotonous, only emitting light of a single color. In response to this situation, we propose a new preparation method of multi-color, non-toxic fluorescent substance and study its fluorescence characteristics.

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