bluuebunny/crossref_metadata_2025 huggingface dataset:
31P NMR Studies on Perfused Liver from Mouse with Chronic Ethanol Ingestion
Authors: Sonawat Haripalsingh M. , Yamamoto Shunji , Leibfritz Dieter
Published: August 2018

Changes in the levels of phosphate metabolites as affected by acute ethanol administration and chronic ethanol ingestion were investigated in perfused mouse liver by 31P NMR spectroscopy. Acute ethanol administration decreases intracellular Pi and the Pi/ATP ratio, and increases phosphomonoester levels in normal-fed animals. No such change was observed in the liver from ethanol-fed mice. Chronic ethanol ingestion renders the liver more prone to ischemia-induced changes in ATP, intracellular Pi, and phosphomonoesters. The Pi/ATP ratio increases fivefold in control mice and fourfold in alcohol-fed mice when ischemia is induced in the presence of ethanol. Intracellular pH of 7.45 ± 0.05 is not affected by ethanol perfusion. Cellular acidosis resulting from ischemia in the presence or absence of alcohol was similar. However, longer period of ischemia leads to an additional 0.11 unit drop in pH in the presence of ethanol.
A Piperidine Amino Acid, 2,4,5-Piperidinetricarboxylic Acid from Clitocybe acromelalga
Authors: Shirahama Haruhisa , Yamano Kimiaki
Published: August 2018

A new piperidine amino acid, 2,4,5-piperidinetricarboxylic acid (11) was isolated from the poisonous mushroom, Clitocybe acromelalga. The structure determination and its biogenetic potential are discussed.
Triterpenes and a Novel Natural Xanthone as Lipophilic Glandular Products in Hypericum balearicum
Authors: Wollenweber Eckhard , Dörr Marion , Roitman James N. , Arriaga-Giner F. Javier
Published: August 2018

Leaves and young twigs of Hypericum balearicum L. exhibit lipophilic glandular products that can be re­ covered by rinsing green aerial parts with acetone. Major components of the resinous material are the triterpenes lupeone and lupeol. The intensely yellow col­ our of the acetone solution is due to a novel natural product, identified as 1,2,5-trihydroxyxanthone.
Lipogenic Enzymes of Rat Liver and Adipose Tissue. Dietary Variations and Effect of Polychlorinated Biphenyls
Authors: Boll Meinrad , Weber Lutz W. D. , Stampfl Andreas , Messner Burkhard
Published: August 2018

The lipogenic enzymes fatty acid synthase (FAS; EC 2.3.1.85), citrate cleavage enzyme (CCE; EC 4.1.3.8), malic enzyme (ME; EC 1.1.1.40), glucose-6-phosphate dehydrogenase (G6PDH; EC 1.1.1.49) and 6-phosphogluconate dehydrogenase (PGDH; EC 1.1.1.44) were investigated in liver and in brown adipose tissue (BAT) of Wistar rats under various dietary conditions and in the presence of 15 to 250 ppm (approximately 0.045-0.75 μmol/kg chow) polychlorinated biphenyls (PCBs).

In response to refeeding starved animals, enzyme activities in both tissues increased to above normal levels and thereafter exhibited pronounced oscillations of their activities. The extent of increase depended on the carbohydrate and fat content of the diet. The lipogenic enzymes could be grouped in two categories according to their sensitivity to dietary carbohydrate: FAS and CCE responded faster to smaller changes in dietary composition, while ME, G6PDH and PGDH required larger changes and more time to respond.

Diet-induced alterations of enzyme activities were of the same order of magnitude in liver and BAT. They were age-dependent, being more pronounced in young animals. Independent of the type of dietary manipulations, activities changed in a coordinate fashion, i.e., the changes of the activities of all 5 enzymes occurred at similar ratios to each other with an identical time course.

Feeding PCB-containing diets resulted in a considerable increase of the activities of the lipogenic enzymes in liver, which was significantly greater with ME, G 6PD H and PGDH. The effect was dose-dependent but transient. In liver the response to PCB feeding was iden­tical in male and female animals, whereas in BAT lipogenic activities increased in females, but decreased in males.

Refeeding starved animals with a PCB-containing diet led to an additional stimulation of the normal refeeding-induced increase of the enzyme activities in liver and BAT. This PCB-induced increase was 2-fold for FAS and CCE, but up to 15-fold for the other enzymes. All PCB-induced effects were significantly less pronounced in old than in young animals.

In primary hepatocytes activities increased in hormone-free medium in the presence of PCBs. While activity was induced in insuline-and triiodothyronine-containing medium, this increase was significantly greater with PCBs present.
Effect of Modification of Arginine Residues on the Activity of Soybean Lipoxygenase-1
Authors: Matsui Kenji , Shinta Hiroyuki , Kajiwara Tadahiko , Hatanaka Akikazu
Published: August 2018

Arginine residues of soybean lipoxygenase-1 was modified with an arginine-directed chemical modifier, 2,3-butanedione. Although inactivation was not visible if the enzyme reaction was monitored under the standard assay condition (83.3 μᴍ linoleic acid dispersed in 200 mᴍ sodium borate, pH 9.0), rapid inactivation was observed with 5 mᴍ sodium borate, pH 8.0. The inactivation was protected by the addition of a substrate, linoleic acid, in the modification mixture. Kinetic analyses indicated that one arginine residue accounted for the inactivation. Enzymological analyses showed that the modification narrowed the pH-activity profile of L-1 and made L-1 sensitive to salt concentration of the assay solution. Strong inactivation by modification was found at low salt concentration and low pH. This was not due to a physical change of the linoleic acid. On the other hand, product specificity of L-1 was not altered after modification. Taken together, the modified arginine residue(s) was thought to be not essential to the catalysis but have an important role in supporting an ideal electrostatic interaction within L-1 and/or between L-1 and a substrate even in sub-optimal reaction conditions.
Why 43 Codons?
Authors: Ferreira Ricardo
Published: August 2018

An attempt is made to answer the question posed by the title of this paper. First we show that in primitive self-replicating oligoribotide systems, selection depended from the very start on the existence of 4 kinds of ribotides, forming 2 complementary pairs. Further selection required that the condensation reactions involving the two last positions of the 3′-end of a growing oligoribotide fragment and the first position of the 5′-end of another fragment were catalyzed by randomly synthesized peptides. This established a codon - amino acid concen­tration correlation and clinched triplet segments as the basis of the translation process. Finally, physical arguments are given to show that the monochirality of the ribotides arose from stereochemical reasons, as firstly described by Wald, but that of the amino acids is the result of natural selection acting during the peptide-assisted stage of oligoribotide growth.
4-Pentadecylpyridine: A Metabolite from Taphrina pruni
Authors: Fuchs Claus T , Spiteller Gerhard
Published: August 2018

Contrary to normal fruit, plums infected with Taphrina pruni show various disease symptoms. A comparative study of chemical constituents has proved, by means of GC and GC/MS. that only infected plums contain 4-penta-decylpyridine. Its structure was confirmed by synthesis: a phosphinenickel complex catalyzed the reaction between 4-bromopyridine and penta-decylmagnesium bromide.

Extraction and chromatography of the cultivated fungus have demonstrated that the com­pound is a fungal metabolite.
Relationship between Activities of Enzymes for the Removal of O2
·- and H2O2 and Nitrogenase in Root Nodules of Phaseolus vulgaris L.
Authors: Epping Bernhard , Hansen Alexander P. , Martin Peter
Published: August 2018

Nodules of Rhizobium leguminosarum bv. phaseoli in symbiosis with Phaseolus vulgaris were compared with regard to their nitrogenase activity and activities of enzymes involved in the removal of O2·- and H2O2 as well as total ascorbate content. Activities of catalase (EC 1.11.1.6), ascorbate peroxidase (EC 1.11.1.11), and total ascorbate content were consist­ently higher in nodules inhabited by bacterial strains with higher nitrogenase activity. Values for superoxide dismutase (EC 1.15.11), and guaiacol peroxidase activity did not differ for the bacterial strains compared. On the other hand, when different plant cultivars were inoculated with the same bacterial strain, high nitrogenase activity did not correlate with a higher activ­ity of the oxygen scavenging enzyms or a higher content of total ascorbate. In this case, values for guaiacol peroxidase activity were greatly enhanced in nodules with lower nitrogen­ ase activity. This may be part of a hypersensitive reaction of the plant cultivar against the bacterial symbiotic partner.

Inhibition of catalase activity in the nodules by addition of triazole to the nutrient solution did not alter nitrogenase activity within the first nine hours after addition. It can be concluded that the activity of catalase, ascorbate peroxidase, and superoxide dismutase is not generally coupled to nitrogenase activity in root nodules of P. vulgaris.
A Receptor Interaction Model for Phenylcarbamate Local Anesthetics
Authors: Kettmann V. , Sivý J.
Published: August 2018

We report here a molecular modeling study of selected conformationally constrained phenylcarbamate local anesthetics in relation to the available pharmacological data that enabled us to develop a receptor-interaction model for this class of drugs. The validity of the model was confirmed on other semirigid analogues prepared for this study. The results suggest that the phenyl ring is most likely involved in a stacking interaction with a complementary receptor site and the tertiary ammonium group is capable of both hydrogen bonding and lipophilic interactions.
Electron Spin Resonance Study of Semiquinones Formed during the Autoxidation of 6-Hydroxy-dopamine (2,4,5-Trihydroxy-phenyl-ethylamine)
Authors: Köhle Heidrun , Schuler Paul , Stegmann Hartmut B. , Roginsky Vitaly A. , Brucheltc Gernot
Published: August 2018

6-Hydroxy-dopamine is easily oxidized in aqueous solutions within a pH range of 7-14. Depending on this parameter and the starting concentration of this catechol at least seven different paramagnetic species can be detected. Cyclization to two different indole derivatives of aminochrome type could be demonstrated and the mechanism of formation is discussed. The indoloquinones can easily be reduced to the corresponding semiquinone by an excess of 6-hydroxy-dopamine. All radicals observed react with ascorbic acid in a redox reaction, forming the corresponding catechol and the ascorbic acid semidione
Effect of Platinum(II) Complexes of Benzoic and 3-Methoxybenzoic Acid Hydrazides on Saccharomyces cerevisiae
Authors: Tabakova Svoboda , Dodoff Nicolay
Published: August 2018

The inhibitory effect of benzoic acid hydrazide (bah) and 3-methoxybenzoic acid hydrazide (mbah) on Saccharomyces cerevisiae strains has been compared to that of their platinum(II) complexes: cis-[Pt(bah)2X2], cis- [Pt(NH3)(bah)Cl2]-0.5 H2O. cis-[Pt(mbah)2X2] and cis- [Pt(NH3)(mbah)Cl2] (X = Cl, Br = I), and cis- [Pt(NH3)2Cl2]. The minimal inhibitory concentrations for bah and mbah were 5000-20.000 μm whereas for their Pt(II) complexes they were much less (25-800 jam) and did not exceed these of cisplatin (100-800 μm ) . The activity of the Pt(II) complexes of bah and mbah varied in wide ranges for the different yeast strains tested. Osmotically unstable mutants were found to be more susceptible. The most active complexes were [Pt(NH3)(bah)Cl2] · 0.5 H2O and [Pt(NH3)(mbah)Cl2
Chemical Structure-Odor Correlation in Series of Synthetic Methylene Interrupted n-Nonadien-1-ols
Authors: Sakoda Yasunobu , Matsui Kenji , Akakabe Yoshihiko , Suzuki Jun , Hatanaka Akikazu , Kajiwara Tadahiko
Published: August 2018

Abstract Chemical structure-odor correlations in the isomers of n-C9-methylene interrupted dienols were explored using synthetic nine isomers of these alcohols. The synthetic dienols were purified by recrystallization or column chromatography of their 3,5-dinitrobenzoate de­ rivatives.

Chemical structure-odor correlations in all the isomers of the purified n-nonadien-1-ols were analyzed by treating the data obtained statistically with the principal component analysis method (Sakoda et al., 1995; Cramer et al., 1988) in comparison with those of n-nonen-1-ols. The odor profiles of the n-nonadien-1-ols were attributable largely to the geometries of the isomers, compared with n-nonen -1-ols (Sakoda et al., 1995). With the principal component analysis, the odor profiles of the series of the dienols were successfully integrated into the first and the second principal components. The first component (PC 1) consisted of combined characteristics of fruity, fresh, sweet, herbal and oily-fatty, and the second component (PC 2) leaf or grassy and vegetable-like. Of the methylene interrupted dienol isomers, (2E ,6Z)-and (3Z,6Z)-nonadien-1-ols which are natural products and have (6Z) in the same, deviated markedly from the other isomers as seen in (6Z)-nonen -1-ol of n-nonen-1-ols. That suggests that the double bond of (ω3Z) was an important factor for natural characteristic odor.
Lipoxygenases in Plants -Their Role in Development and Stress Response
Authors: Rosahl Sabine
Published: August 2018

Lipoxygenases catalyze the hydroperoxidation of polyunsaturated fatty acids and thus the first step in the synthesis of fatty acid metabolites in plants. Products of the LOX pathway have multiple functions as growth regulators, antimicrobial compounds, flavours and odours as well as signal molecules. Based on the effects of LOX products or on the correlation of increases in LOX protein and the onset of specific processes, a physiological function for LOXs has been proposed for growth and development and for the plant response to patho­gen infection and wound stress.
Magnesium Starved Cells of Euglena gracilis - a Possible Model System for Studying Mg2+ Influx?
Authors: Scholten-Beck Gabriele
Published: August 2018

In order to obtain a model which allows to directly study Mg2+ influx into the cell, Mg2+ deficiency was induced in the unicellular photoautotrophic flagellate Euglena gracilis. Lack of Mg2+ in the culture medium leads to a number of morphological, biochemical, and physio­ logical changes in E uglena gracilis. The rate of cell division was reduced under Mg2+-free conditions. Subsequently an enlargement of the cells was observed and they changed from spindle-like to oval shape. The Mg2+-starved cells were well filled with paramylon granules, while their motility and vitality was not impaired. Concurrently with the larger cell size the protein-, carbohydrate-, and chlorophyll content of the cells increased. Further changes were observed in the surface carbohydrates. The proportion of cells with galactose, N-acetyl-galac-tosamine and mannose on the cell surface rose in the Mg2+-starved cultures, shown in a lectin-binding assay. Fucose was found on the pellicle of Mg2+-starved cells only. Cultivation of E uglena gracilis in Mg2+-free medium induced a drastic reduction of the intracellular Mg2+ concentration already after 24 h (from 233 nmol/106 cells to 82 nmol/106 cells). When Mg2+ was made available again, the Mg2+-starved cells took them up rapidly and the intracellular concentration of free Mg2+ rose. As Mg2+ depletion could be induced in Euglena gracilis easily by manipulating the culture conditions and as the cells remained viable, it was con­ cluded that this flagellate can be used as a model organism for studying the Mg2+ uptake of eukaryotic cells.
Radioadapted Chicken Embryo Cells: Challenge Specificity and Alterations in Higher-Order DNA Structure
Authors: Tempel Karlheinz
Published: August 2018

Radioadapted chicken embryo cells (X-irradiation in ovo with 10 cGy at the 14th day of development with priming periods of 24 h) were treated in vitro by challenge doses of 14 different DNA -and/or chromatin-interactive agents, including X-rays. A decrease in the cel­lular damage, as measured by scheduled DNA synthesis, was only observed with X-irradia­tion. Sedimentation of nucleoids as well as viscosity of alkaline lysates from ethidium bro­mide (0.35 - 400 (μg/ml)-, novobiocin (125 -1800 μg/ml)-, and hyperthermia (30 min at 43° and 45°)-treated cells suggest a higher tendency of radioadapted cells to undergo positive DNA supercoiling. When DNA from adapted and non-adapted chicken embryo cells was used as substrate, neither its digestion by DNase I nor the inhibition of DNase I activity by various DNA-interactive agents was changed in primed cells. From the previous investigations as well as from the present results it is concluded that an increase of tightening of protein-DNA interactions within the nuclear matrix is a molecular determinant of the elevated radiation resistance in radioadapted chicken embryo cells.
Latent Oxidative Stress Responses of Ozone-Fumigated Cucumber Plants Are Enhanced by Simultaneous Cold Exposures
Authors: Streb Peter , Schaub Hermann , Feierabend Jürgen
Published: August 2018

Cucumber plants (Cucumis sativus L.) were grown under controlled conditions and fumigated with either O3, diluted automobile exhaust or a combination of both. The ratio of variable to maximum chlorophyll fluorescence (Fv/Fm) was estimated as a measure of PSII activity Activities of the enzymes catalase, glutathione reductase and guaiacol-dependent peroxidase and contents of the antioxidants ascorbate and glutathione were assayed as potential indicators of oxidative stress. The behavior of catalase and of PSII are of particular diagnostic interest because they require continuous repair in light. Exposures of up to 13 days to moderate concentrations of the pollutant gases alone did not induce striking changes in any of the activities that were assayed. A lso when the plants were subjected to an additional stress treatment by exposing them to 4 short cold treatments (2h each at 0 - 4 °C in light on days 12-15 after sowing) which induced marked declines of the Fv/Fm ratio, the chlorophyll content and the catalase activity, these cold-induced symptoms of photodamage were not significantly enhanced by the fumigation treatments. However, increases of the activities of glutathione reductase and peroxidase observed during a period of recovery following the cold-exposures were markedly higher in O3-fumigated plants, as compared to plants grown in filtered air or fumigated with car exhaust alone. The results emphasize that effects of moderate pollutant exposures may be latent or delayed over long time periods and that defence responses can be enhanced when plants are exposed to additional, naturally occurring stress situations.
Direct Release of Ethylene from Methionine and Methionine Containing Peptides by Action of 13-Hydroperoxy-(9cis, 11trans)-octadecadienoic Acid
Authors: Scheick C. , Spiteller G.
Published: August 2018

13-Hydroperoxy-9cis,12trans-octadecadienoic acid (13-LOOH) reacts with methionine and methionine-containing peptides in absence of any other reagent by slow release of ethylene. Ethylene was identified by mass spectrometry and quantified by gas chromatography. The amount of ethylene released in a certain time interval depends on the position of the methionine residue in the peptide chain. Highest rates of ethylene release were measured with peptides carrying methionine at the N-terminus. 13-Hydroperoxy-9cis,12trans-octadecadie-noic acid can be substituted by linoleic acid, lipoxigenase and oxygen. We assume that the instant formation of lipid peroxides after plant injury and the instant release of ′wound ethylene′ are related. Since the initiator tRNA in eucaryontic cells always carries a methionine, all newly produced proteins contain methionine at the N-terminal position and are therefore sensitive to oxidative damage by hydroperoxides of fatty acids.
Partial Molecular Analysis of the psbA Gene in Euglena gracilis Mutants Exhibiting Resistance to DCMU and Atrazine
Authors: Thuillier-Bruston Francine , Calvayrac Regis , Duval Evelyne
Published: August 2018

Mutations conferring herbicide resistance have been detected in two new strains (ZR250 and ZR480) of Euglena gracilis Z by partial gene cloning and sequencing. These mutants were originally derived from Z cells grown in medium containing progressively increasing concentrations of DCMU. Each of these strains have been characterized by measuring their growth kinetics, O2 evolution, and resistance to DCMU and atrazine. Partial sequences of the psbA gene of these strains were compared to those published for strains Z and ZR25. The ZR250 and ZR480 strains were found to be double mutants. Besides the expected mutation S265A , they showed an additional point mutation at codon 219 (equivalent to codon 218 of other organisms). This mutation results in leucine being substituted by phenylalanine. For each of the ZR strains, two growth conditions (with or without DCMU in the medium ) have been compared. The presence of the second mutation (at codon 219) leads to notable increase (20-fold) in resistance to DCMU, whereas the resistance to atrazine is only 2-fold. The presence of DCMU, as the selective agent, was responsible for an enhanced herbicide resistance, irrespective of the concentrations used. Substantial modifications in the rate of cell growth and O2 yields were observed when the maximal concentration (480 μm) of DCMU was used. These modifications were reversible on withdrawal of the DCMU. Thus the reversible adaptative modifications also adds to the mutational effect observed
A Stable Crude Chitinase Solution from Spodoptera litura Pupae and A Search for Its Inhibitors
Authors: Kawazu Kazuyoshi , Ohmshi Shigehiko , Kanzaki Hiroshi , Kobayashi Akio
Published: August 2018

A convenient method for preparing a stable chitinase solution from a pest insect. Spodopteralitura, and a bioassay method for insect chitinase inhibitors using this enzyme solution were developed. Allosamidin, the first insect chitinase inhibitor, exhibited an IC50 of 0.2 μᴍ in the present Spodoptera litura chitinase assay, whereas allosamidin was reported to exhibit an IC50 of 0.7 μᴍ in the Bombyx mori chitinase assay. Thus, the present assay using Spodopteralitura chitinase was 3.5-fold more sensitive than the B. mori chitinase assay. Screening of 300 supernatants of microbial cultures for chitinase inhibitors using the Spodoptera litura chitinase assay found 13 active supernatants
Some Properties of Spectrin-Like Proteins from Pisum sativum
Authors: Bisikirska Brygida , Sikorski Aleksander F.
Published: August 2018

Abstract Proteins cross-reacting with antibodies directed against a-and β-spectrin were recently detected in plant cells. In this report we have studied the ability of these proteins to interact with other components of membrane skeleton such as ankyrin. f-actin and calmodulin. It was found that the polypeptide of high molecular weight reacting with anti-a-spectrin antibody binds calmodulin in Ca2+-dependent manner. Protein complexes containing polypeptides cross-reacting with anti-spectrin antibodies interact with muscle f-actin (in co-sedimentation assay) and with erythrocyte ankyrin (ELISA -type assay). These data further substantiate a possibility of occurrence of spectrin-based membrane skeleton in higher plant cells.
A Particulate Guanylate Cyclase (EC 4.6.1.2) from Growing Yeast Cells {Saccharomyces cerevisiae)
Authors: Eckstein Hans , Schlobohm Heike
Published: August 2018

The detection of cGMP in yeast (Eckstein 1988), but lacking hints at guanylate cyclase from sequencing of the yeast genome, raised questions about existence, isoform, and regula­tion of guanylate cyclase from this organism. We found a particulate guanylate cyclase activity in yeast extracts, exhibiting properties of an integral membrane protein. Characteristics are: pH-optimum at pH 6.8, temperature-optimum around 60 °C, only slight stimulation by Mn2+. Sigmoidal enzyme kinetics indicate allosteric regulation, ATP and Ca2+ act as negative allosteric effectors. The enzyme activity is increased by yeast alpha-1 mating factor, and by sodium nitrite, thus showing properties of particulate as well as of soluble isoforms from other eukaryotes. The activation by alpha-1 mating factor suggests receptor functions, and a role in ascospore conjugation.
Interaction of the Organochlorine Pesticide Dieldrin with Phospholipid Bilayers
Authors: Suwalsky M. , Benites M. , Villena F. , Aguilar F. , Sotomayor C. P.
Published: August 2018

Dieldrin is an organochlorine insecticide highly toxic for human beings. Although its exact mechanism of action is not well known, there is evidence that it acts at the cell membrane level. In fact, the lipophilicity of the pesticide as well as that of the phospholipid bilayer present in biological membranes makes the latter a most likely target for the interaction of dieldrin with living organisms. In order to evaluate its perturbing effect upon cell membranes the pesticide was made to interact with human erythrocytes and molecular models. These studies were performed by scanning electron microscopy on erythrocytes, fluorescence spectroscopy on dimyristoylphosphatidylcholine (DMPC) large unilamellar vesicles and X-ray diffraction on multilayers of dimirystoylphosphatidylcholine (DMPC) and dimyristoyl-phosphatidylethanolamine (DMPE). It was observed that dieldrin particularly interacted with DMPC liposomes and multilayers perturbing its molecular arrangements. However, no effect was noticed on erythrocytes, which might be due to its high cholesterol content.
Self-Assembly in Plant Barrier Biopolymers
Authors: Domínguez Eva , Heredia Antonio
Published: August 2018

A new procedure is given to isolate the components that constitute the translucent lines present in some layered plant cuticles. These electron-translucent lines are mainly composed of fatty acids and n-alkanes. This waxy material is capable to form molecular bilayers with a constant thickness of approximately 5 nm. This special arrangement have a strong contribution in water transport across the cuticle
Effects of Seasonality and Fasting on the Body Mass and Plasma Growth Hormone Concentrations of the Raccoon Dog (Nyctereutes procyonoides) and the Blue Fox (Alopex lagopus)
Authors: Mustonen Anne-Mari , Nieminen Petteri , Hyvärinen Heikki , Asikainen Juha
Published: August 2018

Growth hormone (G H ) promotes growth and endochondral ossification, but it is also important in the response to fasting due to its effects of increasing gluconeogenesis and lipolysis. In this study eleven raccoon dogs and blue foxes were followed for six months and their body mass and GH levels were measured. In November half of the animals of both species were put to a three-week fast. There were no significant differences in the GH levels between the animals of different ages and the subadults and adults both had quite low GH levels in the summer. Fasting had no effect on the GH levels of the raccoon dogs, but the fasting blue foxes had lower GH concentrations than the controls in Nov 16th. The control blue foxes experienced a significant increase in the GH levels in early November and the fasting blue foxes in late November. The GH concentrations of all the raccoon dogs rose in early December. As fasting did not cause an elevation in the GH levels but the concentrations increased with decreasing temperature and shortening daylength, the autumnal GH secretion of these species could be regulated by endogenous seasonal rhythms entrained by exogenous Zeitgebers such as temperature or photoperiod. The autumnal increase of GH levels contributes to the response to fasting as an adaptation to survive the winter months with inadequate nutrition. The raccoon dog which spends the coldest part of the winter in winter sleep seems to be better adapted to a total fast than the actively wintering blue fox.
Luteal ANGPT-TIE system during selected stages of pregnancy, and normal and antigestagen-induced luteolysis in the dog.
Authors: Gram Aykut , Tavares Pereira Miguel , Boos Alois , Grazul-Bilska Anna T , Kowalewski Mariusz P.
Published: August 2018

Rapid establishment of a vascular network is essential for normal functionality of the corpus luteum (CL). The early luteal phase is associated with increased expression of the VEGF-system in canine CL. Acting in synchrony with angiopoietins (ANGPTs), VEGF-system plays major roles in stabilization of blood vessels. However, the expression of the ANPGT-system has not yet been investigated in the dog. Therefore, here, we investigated the luteal expression of ANGPT1, -2, and of their receptors TIE1 and -2, in pregnant dogs at selected time points during pregnancy and at normal and antigestagen-induced luteolysis. Additionally, luteal cells from early CL were incubated with PGE2 and its effects on the ANGPT-system were assessed. Whereas the luteal ANGPT1 was stable until mid-gestation, TIE1 was elevated post-implantation, their expression decreased towards prepartum luteolysis. The ANGPT2- and TIE2-mRNA did not vary during pregnancy. The ANGPT2/ANGPT1 ratio was elevated during prepartum luteolysis. PGE2 increased ANGPT2, but suppressed ANGPT1 levels. None of the ANGPT-system members was affected by antigestagen treatment in mid-pregnancy. Localization of ANGPT1 was predominantly found in the tunica intima and media of vessels and ANGPT2 stained strongly in luteal cells. Both ANGPTs were localized in macrophages. TIE1 stained in the vascular tunica media, in luteal cells and macrophages, whereas TIE2 was colocalized with ANGPT1 in vascular components. In conclusion, high expression of ANGPT1 during the increased presence of VEGFA in early canine CL implies its contribution to vascular network development. The upregulation of the ANGPT2/ANGPT1 ratio during prepartum luteolysis indicates involvement of the ANGPT-system in PGF2a-mediated vascular destabilization.
Conocimiento popular de los mamíferos del Parque Nacional Barra Honda, Nicoya, Costa Rica
Authors: Castillo-Chinchilla Maikol , Piedra-Castro Lilliana , Sandoval-Hernández Iván , Carvajal-Sánchez José Pablo
Published: July 2018

En el mundo, las actividades antrópicas y la pérdida de hábitat tienen efectos negativos sobre la flora y fauna. Se ha comprobado que el estudio del conocimiento popular de grupos faunísticos representa un recurso valioso para la toma de decisiones. El objetivo de este estudio fue evaluar el conocimiento popular sobre los mamíferos terrestres en seis poblados circundantes al Parque Nacional Barra Honda (PNBH), Nicoya, Costa Rica. El análisis de las encuestas se realizó tomando en cuenta la frecuencia y los porcentajes obtenidos en relación con el conocimiento popular, la diversidad de especies, las percepciones sobre los mamíferos terrestres y las actividades de cacería. Los entrevistados mencionaron que, en las áreas externas al PNBH, se pueden observar entre 14 y 18 mamíferos, donde se destaca al puma (Puma concolor), tolomuco (Eira barbara), tepezcuintle (Cuniculus paca) y al venado cola blanca (Odocoileus virginianus). Alrededor del 50 % de los entrevistados identificaron el tepezcuintle y al venado cola blanca como especies que son cazadas con mayor frecuencia. Algunos de los mamíferos identificados por los pobladores de las áreas circundantes al PNBH son catalogados como perjudiciales para los cultivos, animales de granja y ganado, por lo que son cazados de manera indiscriminada.
Parámetros poblacionales y hábitos alimenticios del pargo mancha (Lutjanus guttatus) en el Área Marina de Pesca Responsable Paquera-Tambor, golfo de Nicoya, Costa Rica
Authors: Soto-Rojas Rosa Lidia , Hernández-Noguera Luis Adrán , Vega-Alpízar José Luis
Published: July 2018

El pargo mancha Lutjanus guttatus es una de las especies de peces de mayor importancia comercial capturada en el Golfo de Nicoya, que desde hace muchos años ha venido sufriendo una fuerte presión pesquera, principalmente, por la flota artesanal. De abril del 2015 a abril del 2016, se analizaron 1109 especímenes, con el fin de conocer algunos aspectos biológico pesqueros de la población que se distribuye en el Área Marina de Pesca Responsable Paquera-Tambor en este golfo. La relación longitud total-peso total indica que esta especie posee un crecimiento alométrico negativo; tal población está conformada por cuatro cohortes. La talla media de primera madurez sexual se estimó en 30 cm de longitud total y se determinaron dos periodos máximos de reproducción: el primero de mayo a agosto y el segundo de octubre a noviembre. Los parámetros de crecimiento estimados fueron L∞ = 65 cm de longitud total, K = 0,32 anual y to = -0,42. Las tasas de mortalidad estimadas fueron M = 0,68, F = 2,38; Z = 3,06 y E = 0,77, indicando esta última que la población se encuentra sobreexplotada. Los análisis de hábitos alimenticios sugieren que esta población es generalista con preferencias por crustáceos y peces.
Factores relacionados con la deserción estudiantil en la cohorte 2016, de la carrera de Bachillerato y Licenciatura en la Enseñanza de la Matemática de la Universidad Nacional de Costa Rica (UNA)
Authors: Zamora-Araya José Andrey , Hernández-Noguera Francisco José
Published: July 2018

El estudio abarca la problemática de la deserción universitaria en los estudiantes de la carrera de Bachillerato y Licenciatura en la Enseñanza de la Matemática de la Universidad Nacional de Costa Rica. Se pretende describir a la cohorte 2016 y determinar algunos factores asociados con la deserción, mediante la aplicación de entrevistas telefónicas semiestructuradas a los desertores. Se consideraron, para el análisis descriptivo, variables como la nota del colegio de procedencia, la nota del examen de admisión, la nota tipificada, el índice de desarrollo social, el estrato, el sexo, el tipo de financiamiento del colegio, la condición de beca, la zona de residencia, los créditos matriculados y aprobados. Como resultado de la investigación, se encontró que existen diferencias entre desertores y no desertores en las variables nota de admisión, créditos matriculados y aprobados. Además, la deserción afecta más a las mujeres, estudiantes no becados y de zonas urbanas. Se entrevistaron 11 desertores y se ilustraron tres de esos casos, en los cuales se logró determinar que los aspectos vocacionales, los económicos, los métodos de enseñanza y las expectativas no satisfechas hacia la carrera son los principales factores asociados con el abandono escolar.
Sorption of Polymethine Dyes on Nanographites and Carbon Nanotubes
Authors: Kulinich A. V. , Ishchenko A. A. , Sharanda L. F. , Shulga S. V. , Ogenko V. M.
Published: July 2018

The sorption of functional molecules is a simple rather effective way of modification of nanostructures. The goal of this work is to study the sorption of various polymethine dyes on nanographites and carbon nanotubes. A simple technique affording the preparation of macroscopic amounts (tens of grams) of nanographite from an available starting material has been implemented. The chemical functionalization of the obtained nanographite has been carried out in order to modify its binding properties. Stable suspensions of nanographite and its modifications are obtained in water and organic solvents. It is found that the cationic, anionic and neutral (merocyanine) polymethine dyes do not bind efficiently with the surface of the studiednanographites. Carbon nanotubes of different types (single-, double-, and multiwall) under the same conditions form stable associates with polymethine dyes, what is primarily manifested by a decrease in the absorption intensity of dyes in time, as well as by the additional stabilization of the nanotube suspension. The DFT calculations demonstrate that the studied dyes do not bind strongly, indeed, with nanographites, but they can form more stable aggregates with carbon nanotubes.
Surface Plasmon Resonance in “Monolayer of Ni Nanoparticles/Dielectric Spacer/Au (Ni) Film” Nanostructure
Authors: Yeshchenko O. A. , Kozachenko V. V. , Tomchuk A. V.
Published: July 2018

The dual surface plasmon resonance in Ni nanoparticles in “monolayer of Ni nanoparticles/shellac film/Au (Ni) film” planar nanostructures has been observed in UV-vis absorption spectra. The dependences of the intensity, wavelength, and width of the dual SPR absorption peaks of Ni nanoparticles coupled with an Au (Ni) film on the spacer thickness have been studied in the range of spacer thicknesses of 12–43 nm. The main features of these dependences are an increase of the intensity, the blue shift, and the monotonic behavior of the widths of SPR absorption peaks at a decrease of the spacer thickness. The observed dependences have been rationalized as a result of the plasmonic coupling of the monolayer of Ni nanoparticles withthe metal film and the variation of the dielectric permittivity of the environment of Ni nanoparticles caused by the metal film presence. The stronger dependences of the SPR spectral characteristics of Ni nanoparticles have been observed in the nanostructure containing the gold film comparing to that with a nickel one. Such effect is due to the stronger coupling of Ni nanoparticles with an Au film, and the stronger influence of an Au film on the permittivity of the environment of Ni nanoparticles.
Pulses of the Excitonic Condensed Phase in Semiconductors with Double Quantum Well at Steady Pumping
Authors: Mykhaylovskyy V. V. , Sugakov V. I.
Published: July 2018

The conditions, under which the generation and movement of solitons (regions of exciton condensed phases) occurs in double quantum wells of semiconductors under a stationary pumping and in the presence of an external driving force, are analyzed. It is shown that there is a minimal size of the system, in which a state with moving solitons can be created. The dependence of the minimum value of the driving force necessary for the generation of moving solitons on the size of the system is found.
Electric Field Interaction with Hydrocarbon Flames
Authors: Orlovskaya S. G. , Skoropado M. S. , Karimova F. F. , Chernyak V. Ya. , Vergun L. Yu.
Published: July 2018

The problem of electric-field-assisted combustion for low-melting point hydrocarbons (paraffin wax, n-alkanes) attracts the attention of scientists in relation to the development of paraffin-based propellants. Our study is aimed at the detailed investigation of the dc electric field interaction with the flame of octadecane droplet. We have studied the melting and combustion of alkane particles in the electric field ranging from 33 kV/m to 117 kV/m. It is found that the melting rate decreases distinctly starting with the electric field strength E ∼ 80 kV/m. This effect is more pronounced at high gas temperatures (Ste >1), when the melting time is about a few seconds. So, the melting process slows down in the dc electric field. At the same time, the burning rate constant rises by more than 10 percents. The obtained results can be used to develop efficient and clean technologies of fossil fuels combustion.
Self-Organized Structuring of the Surface of a Metal–Semiconductor Composite by Femtosecond Laser Processing
Authors: Berezovska N. , Dmitruk I. , Kalyuzhnyy A. , Dmytruk A. , Blonskyi I.
Published: July 2018

Peculiarities of the laser treatment of a composite consisting of a thin film of a metal (gold) on the surface of a semiconductor substrate [silicon (100)] have been studied. Micro- and nanostructurings of the metal-semiconductor composite sample have been achieved by the irradiation of its initial surface with a Ti : sapphire femtosecond laser. Laser ablation leads to the patterning of the surface of the composite with laser-induced periodic surface structures (LIPSS) and the formation of semiconductor nanohills, metal nanoparticles, and/or nanowires on the top of hills. The presence of some nanoscale surface features is confirmed by a low-frequency shift of the silicon phonon band in Raman spectra. Prepared microstructured surface barrier solar cells are characterized by means of scanning electron microscopy, optical spectroscopy, and photoelectric measurements.
FTIR and DSC Studies of Binary Mixtures of Long-Chain Aliphatic Compounds: Lauric Acid – Cetyl-trimethylammonium Bromide
Authors: Gavrilko T. , Gnatyuk I. , Styopkin V. , Shcherban N. , Baran J. , Drozd M.
Published: July 2018

Structural and thermal properties of a solid-state binary mixture of long-chain cationic and anionic surfactants (so-called catanionic complexes) composed of cetyltrimethyl-ammonium bromide, [H3C–(CH2)15–N+(CH3)3]Br−(CTAB), and saturated fatty acid (FA), CH3(CH2)12COOH (lauric acid, kC12), are studied. To clarify the effect of intermolecular interactions on the crystalline structure and phase transitions in this class of supramolecular compounds, the 1 : 1 kC12-CTAB binary mixture is investigated by means of X-ray diffraction, differential scanning calorimetry (DSC), and temperature-variable Fourier transform infrared spectroscopy (FTIR). Based on the comparison of the obtained results with those of other CTAB-FA binary mixtures with different alkyl chain length mismatches, the possible molecular packing in the crystal phase of CTAB-FA complexes and the mechanism of successive phase transitions in the condensed state are proposed.
Morphology and Phase Transformation of Copper/Aluminium Oxide Films
Authors: Panthawan A. , Kumpika T. , Sroila W. , Kantarak E. , Thongpan W. , Pooseekheaw P. , Sornphanpee R. , Jumrus N. , Sanmuangmoon P. , Tuantranont A. , Singjai P. , Thongsuwan W.
Published: July 2018

Сopper aluminium oxide (CuAlO2) was successfully prepared within the single-step sparking process at the atmospheric pressure. The as-deposited films were then annealed at 400, 900, 1000, and 1100 ∘C in an oven. The results have shown that the annealing temperature has direct effect on the morphology, phase transformation, and optical properties. CuAlO2 in the delafossite phase was formed on the annealed films at temperatures higher than 900 ∘C. Furthermore, the energy band gaps of the annealed films were linearly increased from 3.3 to 3.8 eV with increasing the annealing temperature from 400 to 1100 ∘C due to a reduction of the oxygen deficit of films at high annealing temperatures.
Energy Spectra Correlation of Vibrational and Electronic Excitations and Their Dispersion in Graphite and Graphene
Authors: Gubanov V. O. , Naumenko A. P. , Bilyi M. M. , Dotsenko I. S. , Navozenko O. M. , Sabov M. M. , Bulavin L. A.
Published: July 2018

The correlation between the vibrational and electron excitation modes in the energy spectra of single-layer graphene and crystalline graphite, as well as the dispersion dependences of those modes, has been studied. The methods of the theory of projective representations of the point and spatial symmetry groups are used for the first time in order to interpret those correlations. The correlations of vibrational and electron excitation spectra and the compatibility conditions for irreducible projective representations in the descriptions of quantum states of graphene and crystalline graphite at various points of their Brillouin zones are determined. For the projective representations of all projective classes belonging to the hexagonal system, standard factor-systems are constructed for the first time. In particular, the factor-systems for electron states are first determined. The results obtained are used to calculate, also for the first time, the correct spinor multiplication tables, i.e. the multiplication tables for elements in double symmetry groups. The developed method is applied to classify all high-symmetry points in the Brillouin zones of single-layer graphene and crystalline graphite with respect to the symmetry type of vibrational excitations.
Yurii Ivanovych Shymans’kyi (1928–1998) (to the 90th anniversary of his birthday)
Authors: Лебовка Микола Іванович
Published: July 2018

July 10, 2018 marks the 90th anniversary of the birthday of the outstanding Ukrainian scientist in molecular physics, one of the founders of the physics of liquid state in Ukraine, Professor, Dr. Sci. in physics and mathematics, Academician of the Academy of Sciences of the Higher Schools of Ukraine Yurii Ivanovych Shymans’kyi.
On the History of Cryogenic Instrument Making in Ukraine
Authors: Zharkov I. P. , Demishev A. G.
Published: July 2018

The history of cryogenic instrument making in Ukraine has been briefly described.
Spectral Particularities of Femtosecond Optical Pulses Propagating in Dispersive Medium
Authors: Ovechko V. S. , Myhashko V. P.
Published: July 2018

We have proposed a refined solution of the wave equation for a dispersive medium without restriction on the duration of an optical pulse. We apply a series of elementary wave packages (EWP) to the representation of superwideband signals (fs pulse). We investigate peculiarities of the propagation of waves with low and high frequencies through the one-resonance medium. We show the existence of a “precursor” for fs optical pulses. We propose a formula for the optical signal velocity (OSV). Its value does not exceed the light velocity in vacuum. We have designed a method of adaptation of EWP-pulses to time-domain spectroscopy.
Generalized Equidistant Chebyshev Polynomials and Alexander Knot Invariants
Authors: Pavlyuk A. M.
Published: July 2018

We introduce the generalized equidistant Chebyshev polynomials T(k,h) of kind k of hyperkind h, where k, h are positive integers. They are obtained by a generalization of standard and monic Chebyshev polynomials of the first and second kinds. This generalization is fulfilled in two directions. The horizontal generalization is made by introducing hyperkind ℎ and expanding it to infinity. The vertical generalization proposes expanding kind k to infinity with the help of the method of equidistant coefficients. Some connections of these polynomials with the Alexander knot and link polynomial invariants are investigated.
Stochastic Diffusion of Energetic Ions in Wendelstein-Type Stellarators
Authors: Tykhyy A. V.
Published: July 2018

The collisionless stochastic diffusion of energetic ions in optimized stellarators of the Wendelstein type has been considered. The phenomenon concerned was predicted earlier in the framework of a simplified theory describing the separatrix crossing by ions. The jumps of the adiabatic invariant in magnetic configurations of a stellarator are calculated. The analysis of the results obtained confirms the importance of the stochastic diffusion and demonstrates that the diffusion coefficient can considerably exceed the available result.
Vibration Spectroscopy of Complex Formation in Aqueous Solutions of Isopropanol
Authors: Kutsyk A. M. , Ilchenko O. O. , Yuzvenko Ya. M. , Obukhovsky V. V. , Nikonova V. V.
Published: July 2018

The formation of molecular complexes in isopropanol-water solutions is studied by means of vibrational spectroscopy techniques. The ATR FTIR spectra of solutions with different mixing ratios are detected. The multivariate curve resolution of the experimental data set shows that the investigated solution could be treated as a four-component mixture, which contains pure isopropanol, pure water, and two molecular complexes.
Aggregation Processes in Hybrid Nanosystem Polymer/Nanosilver/Cisplatin
Authors: Kutsevol N. , Naumenko A. , Chumachenko V. , Yeshchenko O. , Harahuts Yu. , Pavlenko V.
Published: July 2018

Hybrid nanosystems consisting of star-like copolymer Dextran-graft-Polyacrylamide in the anionic form (D-g-PAA(PE)), silver nanoparticles (AgNPs), and cisplatin (cis-Pt) have been synthesized in water and characterized by TEM, DLS, FTIR, and UV-Vis spectroscopies. It is shown that cis-Pt forms a complex with carboxylate groups of the polymer. For the ternary system Polymer/AgNPs/cis-Pt, a change in the hydrophilic-hydrophobic balance of a polymer molecule (due to the complexation with cis-Pt) and the aggregation of macromolecules, as well as to some agglomeration AgNPs, are revealed. The decrease of the antitumor efficiency of the hybrid ternary nanosystem Polymer/AgNPs/cis-Pt in comparison with the Polymer/cis-Pt system is discussed.