bluuebunny/crossref_metadata_2025 huggingface dataset:
Spectrophotometric Estimation of Cefuroxime and Ceftazidime in Bulk and in Dosage Forms
Authors: Amin A. , Khalli H. , Saleh H.
Published: May 2019

Three simple, accurate and sensitive spectrophotometric methods (A, B and C) for the determination of cefuroxime and ceftazidime in bulk samples and in dosage forms are described. They are based on the reaction with nitrous acid forming a nitroso derivatives which can be measured at λmax 350 and 355 nm for cefuroxime (I) and ceftazidime (II), respectively (method A) or by oxidation of drug I or II with an excess of freshly prepared hypobromite and the residual hypobromite was treated with sodium fluorescein at the optimum experimental conditions and measured at λmax at 517 nm (method B). Method C is based on the formation of tris (0-phenanthroline) iron(II) complex (ferroin) upon the oxidation of the studied drug I or II with an iron (III)-o-phenanthroline mixture in acetate buffer solution of pH 3.6 and measuring at λmax 509 nm. Regression analysis of Beer-Lambert plots showed good correlation in the concentration ranges 0.2 – 6.0, 0.2 – 3.2 and 0.1 – 5.6 μg ml−1 for methods A, B and C, respectively. The apparent molar absorptivity, Sandell sensitivity, detection and quantitation limits were calculated. For more accurate results, Ringbom optimum concentration range was 0.2 – 5.6 μg ml−1. The validity of the proposed methods was tested by analysing dosage forms containing the studied drugs I and II. The relative standard deviations were ≤ 1.25% with recoveries 98.6 – 101.4% .
METOPROLOL EFFECT ON FATTY ACIDS COMPOSITION OF CELL MEMBRANE PHOSPHOLIPIDS
Authors: Świerczek-Zięba G. , Lodowska J. , Mazurek U. , Kurkiewicz S. , Wilczok T.
Published: May 2019

It is quite well known that β-blockers influence the stability of cell membranes, but the effect of metoprolol on the composition of cell membrane lipids is not established. On the other hand, synchronous culture of Chlorella vulgaris cells, which consists of cells brought to the same developmental stage by cycling lighting, provides a convenient biological model in unidirectional analyses aimed at assessment of effects of xenobiotics on cells. Advantages of the model include short life cycle and possibility to control metabolic processes of the cells across the broad range. We assessed the effect of metoprolol on fatty acids composition of cell membrane phospholipids in consecutive life cycle stages of Chlorella vulgaris. Lipids were extracted using a chlorofonn/methanol method. Phospholipids were precipitated from the chloroform phase with cold acetone and following centrifugation the pellet of phospholipids was hydrolyzed in alkaline solution. Fatty acids were extracted with petroleum ether and then methylated with BF3-methanol. This protocol produced methyl esters of fatty acids which were subjected to GC-MS analysis. Metoprolol had no effect on the number of progeny cells of Chlorella vulgaris throughout their life cycle at the concentration range tested (5x10-5 M, 5x10-6 M, 5x10-7 M). However, we observed stimulation of biological activity of Chlorclla cells as measured by spectrophotomctry at λ=680 nm. Metoprolol, at the highest concentration, increased phospholipids content in mother cells. Simultaneously, relative amount and saturation level of thc fatty acids remained constant.
Anatomy of the underground parts of four Echinacea-species and of Parthenium integrifolium
Authors: Länger R.
Published: May 2019

Improved descriptions and detailed drawings of the most important anatomical characters of the roots of Echinacea purpurea (L.) MOENCH, E. angustifolia DC., E. pallida (NuTT.) NUTT., and of Parfhenium integrifolium L. are presented. The anatomy of the rhizome of E. purpurea, which was detected in commercial samples, and of the root of E. atrorubens NUTT., another known adulteration for pharmaceutically used Echinacea-species, is documented for the first time. The possibilities and limitations of the identification by means of microscopy are discussed. The anatomical differences between the roots of E. angustifolia, E. pallida and E. atrorubens are notsufficient for differentiation, however, root and rhizome of E. purpurea and the root of Parthenium integrifolium appear well characterized. Because of the highly similar anatomy the microscopic proof of identity and purity of crude drugs of Echinacea must be done with uncomminuted material and the examination of cross sections.
Tetramethyltetrahydro-1,4-anthrachinonazobenzoesäure, ein 5-Lipoxygenase-Inhibitor mit zelldifferenzierender Aktivität.Untersuchungen an 1,4-Naphthochinonen, 28. Mitt. 1)
Authors: Wurm G. , Probst R. , Schwandt S.
Published: May 2019

The combination of 5-lipoxygenase (5-LOX) inhibition and retinoid activity in one molecule could be a suitable too1 for the topical psoriasis therapy. The anellation of the 5-LOX inhibitor 1 with the tetramethylcyclohexane moity to the arotinoid structure 2 does not fullfil this expectation. This compound was not able to differentiate HL-60 cells to granulocytes. The exchange of the 3,5-di-tertbutyl-4-hydroxyphenyl substituent by benzoic acid and the synthesis of 8 resulted in the loss of 5-LOX inhibition also. The construction of 10 by the introduction of an azo spacer between the anthraquinone moity and benzoic acid of 8 finally led to the expected compound: 10 was potent 5-LOX inhibitor and concomitant differentiated HL-60 cells as measured by the NBT test.
KAPILLARELEKTROPHORETISCHE BESTIMMUNG VON KOHLENHYDRAT-ENANTI0MEREN
Authors: Lachmann B. , Noe C.
Published: May 2019

Capillary electrophoresis is a versatile analytical technique for the determination of a very widespread range of compounds. Many applications for the separation of different pharmaceuticals, ions, herbicides and biomolecules such as DNA, proteins and peptides have been published over the last decade. A comparatively new field is the separation and determination of carbohydrates bycapillary electrophoresis, especially the assignment of absolute configuration. These methods will also gain importance in the field of pharmaceutical carbohydrate analysis. In this review a short overview ofthe different methods and separation procedures is given and some applications for the separation of sugar enantiomers are described in more detail.
Die Benzidinblau-Reaktion in der pharmazeutischen Analytik
Authors: H.-J. Kallmayer , B. Trojan
Published: May 2019

Vor mehr als 150 Jahren hat Zinin das unsubstituierte Benzidin (1) synthetisiert und dessen Blaufärbung mit oxidierenden Reagentien beobachtet [1] [...]
Phenylpropanoids and Polyacetylenes from Ligusticum mutellina (Apiaceae) of Tyrolean Origin
Authors: Renate Spitaler , Ernst-Peter Ellmerer-Müller , Christian Zidorn , Hermann Stuppner
Published: May 2019

Roots of Ligusticum mutellina (L.) CRANTZ afforded five major compounds, the phenylpropanoids trans-isoelemicin (1), sarisan (2), and trans-isomyristicin (3), and the polyacetylenes falcarindiol (4) and falcarindiol-3-O-acetate (5). Structures were assigned by 1D- and 2D-NMR spectroscopy. Close inspection of the NMR spectra of falcarindiol-3-O-acetate (5) and comparison with the literature revealed that published NMR data for this compound are most probably attributable to cis or trans Δ2-isofalcarindiol-1-O-acetate (6a/6b). 1H and 13C NMR data for falcarindiol-3-O-acetate are given and trans-isoelemicin (1), sarisan (2), and trans-isomyristicin (3), falcarindiol (4), and falcarindiol-3-O-acetate (5) are reported for the first time from Ligusticum mutellina. Chemosystematic and ethnopharmacological implications of the findings are discussed briefly.
Triflate-mediated Synthesis of 3-(4-Methoxyquinazolin-2-yl)- quinazolin-2,4-(1H,3H)-dione and its Antimicrobial Activity.
Authors: C. O. Usifoh , G. C. Ukoh
Published: May 2019

The synthesis of a novel quinazolinone was accomplished by the reaction of quinazolin- 2,4-(1H,3H)-dione with trifluoromethanesulfonic anhydride in triethylamine. The antimicrobial activity was determined against eight microorganisms. The organisms were all susceptible to 3-(4-methoxyquinazolin-2-yl)-quinazolin-2,4-(1H,3H)-dione 3 at the concentrations used. The gram positive organisms showed more susceptibility than the gram negative ones.
The Behaviour of Arylidene Barbituric Acid and Cyclohexadione Derivatives Towards Tris(dimethy1amino)phosphin
Authors: N. R. Mohame , M. M. T. El-Saidi , S . A. Abdel Aziz , M. F. Zayed
Published: May 2019

Tris(dimethy1amino)phosphine 1 reacted with phenylarylidene barbituric acids 4 to yield the triaminophosphonium dipolar ion adduct 7. 2-Arylidene-1,3- cyclohexanedione 5 and 2-Arylidene-5,5-dimethylcyclohaxane1-,3 -diones 6 reacted with phosphine 1 to produce the dioxyxanthenes 10 and 12, respectively. Structural assignments are based on analytical, chemical, and spectroscopic evidences. A mechanism is proposed to explain the formation of these compounds. The biological acitivity of the new synthesized compounds against Aphis Craccivora, a serious pest infecting many crops in Egypt, was studied.
The Beneficial Interaction Between Enalapril and Danazol in Normal Rat
Authors: M. Mansour , T. El-Hadiyah , O. Ginawi , A. Mostafa , A. Al-Majed , O. Al-Shabanah
Published: May 2019

Danazol, a weekly androgenic, heterocyclic compound with anabolic properties, is used primarily in the treatment of endometriosis and other gynecological complaints. Effects of co-administration of enalapril, an angiotensin converting enzyme inhibitor (ACE inhibitor) with danazol on some biochemical parameters in rats were studied. Treatment of rats with danazol (200mglkg i.p) for 15 days induced a significant elevation of serum aspartate transaminase activity (AST, EC: 2.6.1.1), triglycerides (TG) and induced a significant decrease in serum cholesterol. However, enalapril treatment (20mglkg i.p) for 15 days caused a significant elevation of serum alanine transaminase activity (ALT, EC: 2.6.1.2). Co-administration of danazol and enalapril significantly lowered the elevated levels of serum transaminases enzyme activities and serum TG. It could be concluded that long term treatment with enalapril might be beneficial in patients danazol in clinical situations through protection against undesirable side effects.
Synthesis of new piperidine and cyclohexylamino-spiro derivatives as potential anticalcium agents
Authors: Isabel Sánchez , Maria Dolors Pujol , Gérald Guillaumet , Roy Massingham , André Monteil
Published: May 2019

The spiropiperidine derivatives have considerable importance in pharmaceutical chemistry due to their effects on different biological systems [...]
Bioactives properties of extracts from moroccan oil shale
Authors: Mina OUMAM , Abdelkrim ABOURRICHE , Hassan HANNACHE , Abdelmjid ABOURRICHE , Ahmed BENNAMARA , M'hamed CHARROUE , R. PAILLER , R. NASLAIN
Published: May 2019

Oil shale have constituted for a long time, an economical hope for countries which possesses important reserves of these rocks and view to use them as an energy source substitute for petroleum [...]
Enhanced Dissolution Rate of Tiaprofenic Acid Using Gelucire®44/14*
Authors: M. S. Saygh , G. Uzunkaya , Y. Özsoy , A. Araman
Published: May 2019

Tiaprofenic acid (TA), racemic (5-benzoyl-2-thieny1)-propionic acid (Fig. 1) is a 2-aryl propionic acid derivative nonsteroidal anti-inflammatory drug (1) [...]
Efficient Synthesis of Nα,N-Disubstituted α-Aminocarbohydroxamic Acids
Authors: Detlef Geffken , Alf Ploetz , Hans v. Zydowitz
Published: May 2019

The title compounds 3 can be prepared in good yields by the reaction of N-substituted α-chlorocarbohydroxarnic acids 2 and primary amines in dirnethylacetarnide as solvent.
Tetrahydro-2H-1,3,5- thiadiazin-t-thione Derivatives of The optical Isomers of Phenylalanine, Synthesis, Comparative Stability Study and Antifungal Activity
Authors: Tarek Aboul-Fadl , Mahrous Osman
Published: May 2019

In order to investigate the effect of the optical properties of the 5-substituent on the stability and the antihngal activity of tetrahydro-2H-1,3,5-thiadizine-2-thione (THTT) moiety, optical isomers and racemic mixture of phenylalanine were incorporated in the 5th position of THTT to afford derivatives 2a-g. Chemical and enzymatic stability of these derivatives were studied in vitro in aqueous buffer solution of pH 7.4, physiological pH, and 80% human plasma at 37°C using HPLC. The chemical and enzy'matic degradation rates of the tested compounds revealed that the optical properties of the 5-substituent of THTT moiety have no role on their stability at the investigated media. However, the chemical nature of the 3-substiuents has a significant effect on their chemical and enzymatic liability as 3-aralkyl derivatives, 2f and 2g , were the least stable compounds under the investigation conditions. Solid state stability of these derivatives was studied using Differential Scanning Calorimetry (DSC). In spite of the distinguished DSC curves of the racemic cornpounds from that of the corresponding single optical isomers no constant pattern of their thermal stability was observed. The antifbngal activity of 2a-g, was investigated in vitro against Cnndida albicans, C. parasilosis and C. stellatoidea using tube dilution method. No role for the optical properties of the tested compounds on their antifungal activity was observed. The utmost antihngal activity revealed by compound 2g which has 3-phenethyl substituent. Moreover, 2g has the highest lipophilicity and the most susceptible compound for both chemical and enzymatic degradations.
Inversvoltammetrische Bestimmung von Metallionen in mit Hilfe von Nährlösungen kultivierten Solanaceen
Authors: Riße D. , Lahl H. , Unterhalt B.
Published: May 2019

The uptake of Pb, Cd, Cu, Zn into the leaves and roots of Datura stramonium and Hyoseyamus niger, grown in nutrient solutions, is measured by Differential Pulse Anodic Stripping Voltammetry (DPASV). In the leaves of the plants only the contents of Cd and Zn, not those ofPb and Cu, increase by adding these ions to the medium.
Tropane alkaloids from a Brazilian bark traded as "Catuaba"
Authors: Glasl Sabine , Presser Armin , Werner Ingrid , Haslinger Ernst , Jurenitsch Johann
Published: May 2019

Dichloromethane extracts of a Brazilian bark assigned as Anemopaegma mirandum contained four tropane alkaloids. MS-, UV-, IR-, 1H NMR-data and specific optical rotation allowed the identification of catuabin C and its 7-exo-hydroxy-20-methyl-derivative. As no alkaloids are described for Anemopaegma these results indicate heterogeneity for the investigated drug and require a further review.
Adamantam Derivatives, Part 111* : Synthesis of Some Aminoadamantanes as Novel Antitumor Agents
Authors: El-Sherbeny M. , Youssef K. , Mahran M.
Published: May 2019

New series of 1-(1-adamantyl)semicarbazide 3a, 1-(1-adamantyl)4(4-subsMuted pheny1)semicarbazides 3b-e, 1-(1-adamantyl)-3-(subsMuted aminosulfonyl)ureas 5a-g, 1-(1-adamantyl)-4-(1-adamantylamino-methylene)-semicarbazide 7, 1-(1-adamantyl)-4-(1-adamantylcarbonylmethyl)semicarbazide 8, 1-(Iadamantyl)-4-acylsemicarbazides Sad and 1-(1-adamantyl)-4-(1-adamantylaminocarbonyl) thiosemicarbazide 10 have been synthesized and tested for their anMumor activity. Among them, compounds 3a, 5a, 9a. and 9d exhibited a broad spectrum antitumor activity with full panel (MG-MID) median growth inhibition (GI50) of 1 0.5, 12.0, 6.8 and 5.5 μM respectively. In addition, compounds 3a, 3c, and 5d proved to be of moderate selectivity toward leukemia cell lines wrth ratios of 3.0, 3.9 and 4.0 respectively. Moreover, compounds 5a and 5g showed moderate selectivrty toward melanoma cell lines with ratios of 3.6 and 4.4 respectively. The detailed synthesis, specroscopic and biological data are reported.
Method Development for Separation of Active Ingredients in Cold Medicines by Micellar Electrokinetic Chromatography
Authors: Suntornsuk Leena , Pipitharomel Ongart , Wilairat Prapin
Published: May 2019

Separation of nine commonly used active ingredients in cold medicines, were demonstrated by micellar electrokinetic chromatography. The ingredients included paracetamol, chlorpheniramine maleate, diphenhydramine hydrochloride, triprolidine hydrochloride, phenylpropanolamine hydrochloride, dextromethorphan hydrobromide, loratadine, aspirin and caffeine. Effects of buffer concentrations, pH, organic modifiers and capillary length were investigated. The optimum conditions were achieved in 10 mM sodium dihydrogenphosphate-sodium tetraborate buffer, pH 9.0, containing 50 mM sodium dodecyl sulfate and 28% v/v acetonitrile using the effective length of 50 cm, the separating voltage of +15 kV and the capillary temperature of 30°C. Separation of all peaks was obtained within 28.4 min with a resolution of 1.2.
In vitro Studies on Sustained Release Suppository Formulations of Tiaprofenic Acid with Sucrose Fattv Acid Ester
Authors: Gūngör Sevgi , Orlu Mine , Özsoy Yildiz , Araman Ahmet
Published: May 2019

The objective of this study was to evaluate the performance of Sucro Ester 7 (sucrose distearate) as additive for preparing sustained release suppositories of tiaprofenic acid. Suppocire AIM (semi-synthetic glycerides) was used as suppository base and formulations were prepared containing different ratios of sugar ester: Suppocire AIM. Content uniformity, disintegration time and in vitro release characteristics of suppositories were investigated. Significant decrease in the extent of drug release was observed with the increase in the content of sugar ester, which was due to the longer disintegration time of suppositories.
Synthese von thienoanalogen Zimtsäurederivaten mit Hilfe der Heck Reaktion [1]
Authors: Erker Thomas , Handler Norbert
Published: May 2019

Ausgehend vom entsprechenden Bromthiophenderivat und Acrylsäurederivat wurden die optimalen Bedingungen für eine Heck-Reaktion erarbeitet. Dabei wurde der Einfluss der Mengenverhältnisse der Reaktanden bzw. des Katalysators und Co-Katalysators sowie des Lösungsmittels und der Temperatur auf die Umsetzung untersucht.
Erratum to "Tropane alkaloids from a Brazilian bark traded as 'Catuaba'*" [Scientia Pharmaceutica 71,113-119 (2003)]
Authors: Glasl Sabine , Presser Armin , Werner Ingrid , Haslinger Ernst , Jurenitsch Johann
Published: May 2019

The authors regret that the chemical structure of compound 2 was indicated incorrectly as catuabine C. [...]
Analysis of the sesquiterpenes in Achillea species usinq liquid chromatography-mass spectrometry with positive ion atmospheric pressure chemical ionisation
Authors: Rothwangl-Wiltschnigg Katharina , Glasl Sabine , Werner Ingrid , Reznicek Gottfried
Published: May 2019

The species of the Achillea millefolium group contain different sesquiterpenes which are of chemotaxonomical and pharmacological interest. Therefore the HPLC analysis of these compounds is a fundamental task for the quality control of Achillea samples. As difficulties in identification solely on the basis of retention times may arise, the LC was coupled with atmospheric pressure chemical ionisation mass spectrometry (APCI-MS) allowing a selective and sensitive detection and thus the clear identification of the sesquiterpenes.
lnvestiaations for the Preparation of new Pyrazolo[4,3-d]isothiazole Derivatives
Authors: LIPNICKA Urszula , JASZTOLD-HOWORKO lzabela
Published: May 2019

Synthesis of 5-acylhydrazine derivatives of ethyl 3-methyl-4-isothiazolo-carboxylate and their transformations under alcoxides influence have been described and presented.
Application of Ion Associate Formation for Conductimetric Determination of Dothiepin Hvdrochloride in Pharmaceutical Formulations by Using Trioxalato Complexes
Authors: Youssef Ahmed
Published: May 2019

A simple titrimetric method is described for the determination of dothiepin hydrochloride. The method is based on titrating the cited drug with potassium salts of trioxalato-ferrate (III) (TOXFe), trioxalato-chromate (III) (TOXCr), trioxalatoaluminate (III) (TOXAI) and trioxalato-cobaltate (III) (TOXCo). The end point was located conductimetrically. The effect of solvent, molar ratio, reagent concentration and temperature were studied. Based on conductimetric measurements at 25 °C, the solubility, solubility product, free energy (ΔG) and entropy changes (ΔS) of the ion associates were calculated. Calculations of the enthalpy change (ΔH) are based on atomic absorption measurements of the solubility of the ion associates at different temperatures. The method allowed the determination of 6.63-29.87, 3.31-49.78, 9.95-49.78 and 3.31-33.19 mg of the studied drug using TOXFe, TOXCr, TOXAl and TOXCo, respectively. The method was further applied successfully to some dosage forms containing the cited drug, and the obtained results were compared favorably with those previously given by the official method.
Swertia Chirata Buch.-Ham. ex Wall. (Gentianaceae), an Endanaered Himalavan Medicinal Plant: Comparative Study of the Secondary Compound Patterns in Market Drua. In Vitro-Cultivated, and Micropropaaated Field Qrown Samples
Authors: Wawrosch Christoph , Hugh-Bloch Andreas , Hostettmann Kurt , Kopp Brigitte
Published: May 2019

Samples of the Himalayan medicinal plant Swertia chirata obtained from a local market in Nepal, from a micropropagated field cultivated clone, and from two in vitro-clones were compared by means of HPLC. The substance patterns of methanolic and dichloromethane extracts of the in vivo grown materials showed good conformity while in the samples from tissue culture major compounds were missing. Our findings confirm that the secondary metabolism of in vitro-cultivated plants normally differs from that of plants in their natural environment. Furthermore, the compound pattern of plants produced through micropropagation and subsequently cultivated in the field is comparable to that of plants collected from the wild. As an alternative to the uncontrolled depletion of the natural resources a sustainable use of Swertia chirata could hence be achieved by controlled field culture of micropropagated plants.
Pvrrolizidine Alkaloid Containina Plants Used in Mongolian Traditional Medicine: Lappula Myosotis Moench.
Authors: Wiedenfeld Helmut , B. Amarsanaa , D. Altanchirneg , S. Narantuya
Published: May 2019

Lappula myosotis Moench. (Boraginaceae) is a plant growing wide-spread in the Mongolian Aimags Khubsgul, Khangai, Khentei, Mongol dahurica, Altai and Alasha Gobi [1]. From this plant four pyrrolizidine alkloids were isolated and their structures determined using spectroscopical methods: lycopsamine, intermedine and their acetylderivatives. This plant is used in the Mongolian traditional medicine externally but on account of its high level of alkaloids (~ 0.2%) the usage of L. myosotis may be hazardous for humans.
Colorimetric and Atomic Absorption Spectrometric Methods for the Determination of Hyoscine N-Butylbromide in Pharmaceutical Formulations Using Cobalt (II) and Chromium (III) Thiocyanate Complexes
Authors: Issa Yousry M , Youssef Ahmed F A , Awady Mohamed A
Published: May 2019

Two simple and sensitive colorimetric and atomic absorption spectrometric procedures have been established for determination of hyoscine N-butylbromide (Hyo.Br) in pure form and in pharmaceutical formulation. The methods are based on formation of an insoluble coloured ion-associate between the examined drug and tetrathiocyanatocobaltate (CoTC) or hexathiocyanatochromate (CrTC). The first method involves extraction of Hyo-CoTC and Hyo-CrTC ion-associates with methylene chloride and isobutyl alcohol, followed by measuring the absorbance at 630 and 557 nm, respectively. Optimization of the extraction conditions is investigated. Beer's law is obeyed in the concentration ranges 144.20-865.20 and 72.00-640.00 μg/ml using CoTC and CrTC, respectively. The molar absorptivities, Ringbom ranges, Sandell sensitivities and quantification and detection limits are also calculated. The second method is based on measuring the absorbance of the excess cobalt or chromium in the aqueous solution, after precipitation of the drug, at 240.7 and 357.9 nm using atomic absorption spectrometer, respectively. Linear application ranges, characteristic concentrations and detection limits of Hyo.Br are 0.404-1.617 mg/ml, 16.11 and 10.78 μg/ml in the case of CoTC, while 0.040-0.283 mg/ml, 29.50 and 2.70 μg/ml in the case of CrTC. The present methods have been successfully applied for the determination of the drug in commercial dosage form. The data obtained by the developed methods are compared with the official one.
Analytic Formulation of 21 cm Signal from Cosmic Dawn: Lyα Fluctuations
Authors: Raste Janakee , Sethi Shiv
Published: May 2019

We present an analytic formalism to compute the fluctuating component of the H i signal and extend it to take into account the effects of partial Lyα coupling during the era of cosmic dawn. We use excursion set formalism to calculate the size distribution of randomly distributed self-ionized regions. These ionization bubbles are surrounded by partially heated and Lyα coupled regions, which create spin temperature T

S
fluctuations. We use the ratio of number of Lyα to ionizing photons (f

L
) and number of X-ray photons emitted per stellar baryon (N
heat) as modeling parameters. Using our formalism, we compute the global H i signal, its autocorrelation, and its power spectrum in the redshift range 10 ≤ z ≤ 30 for the ΛCDM model. We check the validity of this formalism for various limits and simplified cases. Our results agree reasonably well with existing results from N-body simulations, in spite of following a different approach and requiring orders of magnitude less computation power and time. We further apply our formalism to study the fluctuating component corresponding to the recent observation by the Experiment to Detect the Global Epoch of reionization Signature (EDGES) that shows an unexpectedly deep absorption trough in the global H i signal in the redshift range 15 < z < 19. We show that, generically, the EDGES observation predicts a larger signal in this redshift range but a smaller signal at higher redshifts. We also explore the possibility of negative real-space autocorrelation of spin temperature and show that it can be achieved for partial Lyα coupling in many cases corresponding to simplified models and a complete model without density perturbations.
Recurrent CME-like Eruptions in Emerging Flux Regions. II. Scaling of Energy and Collision of Successive Eruptions
Authors: Syntelis P. , Archontis V. , Tsinganos K.
Published: May 2019

We present results of three-dimensional MHD simulations of recurrent eruptions in emerging flux regions. The initial numerical setup is the same as that in the work by Syntelis et al. Here, we perform a parametric study on the magnetic field strength (B
0) of the emerging field. The kinetic energy of the produced ejective eruptions in the emerging flux region ranges from 1026 to 1028 erg, reaching up to the energies of small coronal mass ejections. The kinetic and magnetic energies of the eruptions scale linearly in a logarithmic plot. We find that the eruptions are triggered earlier for higher B
0 and that B
0 is not directly correlated to the frequency of occurrence of the eruptions. Using large numerical domains, we show the initial stage of the partial merging of two colliding erupting fields. The partial merging occurs partly by the reconnection between the field lines of the following and the leading eruption at the interface between them. We also find that tether-cutting reconnection of the field lines of the leading eruption underneath the following eruption magnetically links the two eruptions. Shocks develop inside the leading eruption during the collision.
Jugement moral et désaccord persistant
Authors: Jaffro Laurent
Published: May 2019

Le propos est d’éclairer les conditions du désaccord réel dans l’épistémologie des jugements moraux. Il semblerait que le subjectiviste en morale puisse s’accommoder du fait du désaccord plus facilement que le réaliste. Le premier peut rapporter le désaccord à la diversité des préférences individuelles ou sociales que les évaluations manifestent. Le second semble peiner à en rendre compte dans des contextes où les conditions informationnelles d’une évaluation sont remplies. L’article défend une troisième approche, attentive à l’épistémologie de l’évaluation, qui met l’accent sur la manière dont les jugements de valeur moraux dépendent essentiellement de raisons. En morale comme ailleurs, juger, c’est entre autres choses assumer une responsabilité à l’égard d’un verdict qui est susceptible d’être justifié.
Terrorisme, imaginaires sociaux et mobilités touristiques : comparaison France/Tunisie
Authors: Mamontoff Anne-Marie
Published: May 2019

L’étude comparée entre la France et la Tunisie depuis 2012 concernant l’effet des attentats terroristes sur les fréquentations touristiques met en évidence des résultats contrastés. En France, malgré un nombre d’attentats très élevé, le tourisme est reparti à la hausse assez rapidement. En revanche, la Tunisie, qui a eu très peu d’attentats impactant le tourisme a subi un effondrement touristique conséquent. Cette différence s’explique par des effets conjugués de contextes sociaux et de « stratégies cognitives » des voyageurs. Le contexte français renvoie une image rassurante, en raison d’un État démocratique et laïque et une sécurisation optimale. Ceci permet alors l’activation de stratégies ou « biais cognitifs » chez les individus, destinés à « ignorer » le risque terroriste pourtant assez probable. La Tunisie affiche un État non démocratique où les pouvoirs politique et religieux vont de concert et, même si le risque terroriste est beaucoup moins probable qu’en France et le pays très sécurisé, il renvoie l’image d’un contexte à risque. Dans ce cas, les voyageurs décodent cette destination à partir de la représentation sociale du terrorisme, dans laquelle l’Islam est contaminé par le terrorisme, ce qui amène de surcroît à classer la Tunisie dans la catégorie des pays dangereux.
José Luis : portrait satirique d’un bourreau dans un pays en plein essor touristique ( El Verdugo de Luis García Berlanga, 1963)
Authors: Picod Claire
Published: May 2019

S’inspirant d’un fait réel, le film El Verdugo du cinéaste espagnol Luis García Berlanga (1963) se livre à la satire d’un bourreau qui incarne la répression à l’époque franquiste, dans une Espagne où le tourisme est une activité prospère et florissante. Le cinéaste oppose à ce titre deux mondes antagonistes : l’univers idyllique des touristes à celui de la féroce dictature espagnole incarnée par José Luis, bourreau récemment promu. Il dépeint ce dernier comme la victime d’un système et non comme le monstre qu’il incarne généralement dans l’imaginaire collectif. Son rêve de voyage va progressivement tourner pour lui à une descente aux Enfers...
Violences aux frontières. « Décomposition » et « recomposition » réelles et symboliques des territoires
Authors: Fleurdorge Denis
Published: May 2019

Ce texte propose une réflexion sur les formes de violences à l’œuvre dans un monde aux frontières ouvertes par une généralisation d’une mondialisation économique. L’analyse se portera sur les effets de la « décomposition-recomposition » des frontières et des limites confrontées aux actes de violence du terrorisme contemporain. L’usage de la violence, à la fois mesuré dans les formes et diversifié dans les moyens, contraint le terrorisme à désigner « ses ennemis » et à reconstruire des frontières à la fois réelles et symboliques.
Le droit des contrats suscite-t-il la confiance du touriste ? Le régime particulier du contrat de vente de voyages à forfait
Authors: Bally Romain
Published: May 2019

Les menaces et les attaques contre un territoire entraînent inéluctablement des conséquences économiques, à tout le moins, de manière provisoire. Le tourisme est l’un des premiers secteurs impactés. Les effets moins directs sont bien connus : le secteur de l’assurance augmente ses primes, réduit ses garanties, la confiance des consommateurs s’érode... Ces effets pernicieux justifient l’intervention des pouvoirs publics qui sont, en quelque sorte, les premiers secours pour préserver autant que faire se peut l’élan de croissance du pays. Cependant, cette action doit être limitée dans le temps et dans son champ d’application car ce sont les acteurs privés qui doivent être au centre du processus : sécuriser, rassurer, guérir et rééduquer la demande touristique. Nous profiterons de cette opportunité afin d’interroger la fonction régulatrice de la règle de droit. L’acte contractuel – représentation juridique de l’échange économique – est-il le berceau d’où peut renaître la confiance du consommateur, quitte à ce que la loi stimule, force un peu, « res-suscite » ce sentiment ? Ces quelques lignes auront pour modeste ambition d’étudier le régime d’un contrat particulier, le contrat de vente de voyages à forfait, pour tenter de démontrer comment le droit français des contrats, et plus particulièrement le droit consumériste, participe à protéger la confiance juridicisée pour mieux susciter la confiance dans le marché .
Development of the Clinical Learning Environment Inventory: Using the Theoretical Framework of Learning Environment Studies to Assess Nursing Students' Perceptions of the Hospital as a Learning Environment
Authors: Chan Dominic
Published: May 2019

ABSTRACT

Clinical learning is an integral part of nursing education; yet, clinical education has been problematic. Why are some clinical experiences better than others? Various studies have indicated that not all practice settings are able to provide student nurses with a positive learning environment. The clinical learning environment is a multidimensional entity with a complex social context. Classroom learning environment research based on psychosocial educational conceptual frameworks has been well established in the past 30 years, with evidential benefits. Previous research on clinical learning environment was examined. However, minimal studies have been conducted on hospital learning environments from the psychosocial educational perspective. To maximize nursing students' clinical learning experiences, the author developed the Clinical Learning Environment Inventory based on the theoretical framework in psychosocial education.
A New Approach to the Numerical Modeling of Pure Metal Solidification
Authors: Ciesielski Mariusz , Mochnacki Bohdan
Published: May 2019

Solidification and cooling processes proceeding in the metal domain can be described in different ways. One of them consists in the application of the Fourier-type equation in which the additional term (source function) controlling the solidification process is introduced. In this paper this type of energy equation is used, but for the phase change modeling the equation discussed is in some way transformed. Such a modification is possible if one considers the pure metal for which the solidification point is a constant value. The numerical model used at the stage of computations is based on the Control Volume Method. In the final part of the paper, examples of computations are shown.
Discrete Wavelet Analysis of Electrochemical Current Noise of a High-Alloy Cast Steel in Sulfuric Acid and Sodium Chloride Solution
Authors: Mandel Marcel , Kietov Volodymyr , Krüger Lutz
Published: May 2019

The electrochemical current noise signal of a high-alloy cast steel was investigated in a 0.1 M sulfuric acid solution and in a 5 wt.% sodium chloride solution. In the sulfuric acid solution, the current time signal reveals characteristic spikes of high amplitudes. In the chloride containing solution, spontaneous power drops with a subsequent recovery of comparatively low intensity characterize the noise signal. Both noise records were analyzed by the discrete wavelet transform. For the noise signal in the sulfuric acid solution, the received wavelet coefficients exhibit the highest values in the fine scale, which signal the dominance of short-time corrosion events that were attributed to the observed hydrogen bubble evolution. In the chloride containing medium, the signal decomposition by the wavelet analysis reveals the highest coefficients predominantly in the coarse scale, indicating a preferred initiation of corrosion processes of high duration. The subsequent observations by scanning electron microscopy, reveal an attack by micro pitting, which is associated with the noise events.
Mechanical, Thermal and Electrical Characteristics of Conventionally Cast and Cold-Rolled 5754-Sc-Zr Aluminium Alloy
Authors: Vlach Martin , Kodetová Veronika , Kudrnová Hana , Leibner Michal , Vlček Marián , Šíma Vladimír , Procházka Ivan , Málek Jaroslav , Očenášek Vladivoj
Published: May 2019

The effect of cold-rolling on mechanical, thermal, and electrical properties as well as microstructure behaviour of the Al-2.93wt.%Mg-0.34wt.%Mn-0.33wt.%Si-0.22wt.%Fe-0.19wt.%Cr-0.24wt.%Sc-0.06wt.%Zr was studied. The material was investigated during step-by-step isochronal annealing in a temperature range from room temperature up to 540 °C and during isothermal annealing at 200, 450 and 550 °C. Precipitation reactions were studied by electrical resistometry, conductivity, (micro) hardness measurements and differential scanning calorimetry. The hardening effect appears due to the additional precipitation of the Al3Sc and/or Al3(Sc,Zr) particles. The distinct changes in residual resistivity ratio above ~ 330 °C are probably caused by precipitation of the Mn (,Fe,Cr)-containing particles. This precipitation process is highly influenced by cold rolling but it has a negligible effect on hardness. The apparent activation energy values for additional formation of the Al3Sc and/or Al3(Sc,Zr) particles were determined. The kinetics of the Al3(Sc,Zr)-phase precipitation seems to be independent of Mn-and Mg-addition in the studied alloys. A partial recrystallization of the cold-rolled alloy was registered by electron backscatter diffraction after annealing at 550 °C. The initial difference in microhardness introduced by cold rolling is almost removed after annealing at 550 °C/30 min.
Mechanical Properties of Bamboo Charcoal (BC)/Poly(Lactic) Acid (PLA) Composites
Authors: Srisuk Rapeeporn , Techawinyutham Laongdaw , Koetniyom Wantana , Dangtungee Rapeephun
Published: May 2019

The influence of bamboo charcoal (BC) in Poly (lactic) acid (PLA) matrix as masterbatch was studied on mechanical 40:60, 50:50 and 60:40 of masterbatch. BC MBs were diluted at 1 phr, 3 phr, and 5 phr. BC showed even distribution in PLA matrix; however,, it decreased compatibility in the matrix. The infusion of BC in PLA matrix enhanced the tensile modulus; however, there was a reduction in the tensile strength and the elongation at break. It could also be ascertained that there is no signification difference in the hardness of BC/PLA composites compared with neat PLA. The addition of BC slightly decreased shear viscosity of the composites. The optimal BC content in the composites was found to be 2.82wt.% (5 phr 60:40).
Fabrication and Surface-Enhanced Raman Scattering Activities of Cross-Linked Polyvinyl Alcohol/Ag Nanofibers
Authors: Juntarasena Komkrit , Samransuksamer Benjarong , Horprathum Mati , Triroj Napat , Jaroenapibal Papot
Published: May 2019

This work describes the fabrication steps and surface-enhanced Raman scattering (SERS) activities of the cross-linked polyvinyl alcohol (PVA)/Ag nanofibers. The water-insoluble electrospun PVA/Ag nanofibers were achieved by post-electrospinning treatment processes. Physical crosslinking was induced by heat treatments, while chemical crosslinking took place through the reactions with glutaraldehyde (GA). Scanning electron microscopy (SEM) images have shown that cross-linked PVA/Ag nanofibers remained mostly intact after immerging in water for 30 min. The testing of SERS activities was performed on these substrates using the methylene blue (MB) molecules as tested substances. The results have shown that the PVA/Ag nanofibers can be used as SERS substrates for rapid screening of biochemical substances. The Raman enhancement factor (EF) of approximately 104 corresponding to the detection limit of 10-4 M of MB molecules was achieved.
Enhancement of Graphene Oxide Deposition on Stainless Steel in Presence of Iodine
Authors: Madih Kholoud , El-Shazly Ahmed Hassan , Hares Essam
Published: May 2019

In this study, Graphene Oxide (GO) was prepared by modified Hummers method and characterized by X-ray diffraction technique (XRD). The characteristic peak of GO was observed at 2=10.94° compared to graphite’s peak at 2 = 26.4°. Aqueous stable suspension of GO was prepared, and its stability was confirmed using Zeta potential and found to be-28.9 mV. Electrophoretic Deposition (EPD) process of GO on stainless steel strips was investigated. The EPD process was optimized to obtain a large amount of deposited GO layer. The optimal applied voltage was found to be 30 V and optimal deposition time was 480 seconds. At the optimum conditions, the effect of the addition of iodine was investigated for its effect on the deposited layer homogeneity. Visual investigation of samples indicated that the homogeneity of the GO coated layer was enhanced in the presence of iodine and confirmed by scanning electron microscope (SEM).
MOF-Modified High Permeability Polyimide Membrane for Gas Separation
Authors: Bernabe Dante P. , Caparanga Alvin R. , Hu Chien Chieh , You Sheng Jie , Lee Kueir Rarn , Lai Juin Yih
Published: May 2019

This study explored the application of MOF-modified membrane for gas separation. Microporous aluminum fumarate (A520) was used to modify polyimide (PI) membrane using N-methylpyrrolidone (NMP) as solvent. The MOF-modified mixed matrix membrane (MMM) was subjected to gas permeability tests, using gas permeability apparatus (GPA). GPA results showed that adding 10wt% MOF to the membrane increased permeabilities of N2 and CO2 gases by up to 34%, and by 19% for O2 gas, without compromising selectivity. Further increasing MOF loading beyond 10wt% considerably decreased selectivities despite significantly increased permeabilities. Cahn adsorption experiment confirmed and supported this GPA data. These results indicate that MOF were successfully intercalated with the polymer as revealed by scanning electron microscope (SEM) images. Other characterizations like dynamic mechanical analysis (DMA), x-ray diffraction (XRD), and positron annihilation lifetime spectroscopy (PALS) showed that the interface and mechanical properties of the MMM also improved. MOF loading beyond 10wt% revealed aggregations forming non-selective voids that probably caused lowered selectivity.
Experimental Investigation, Modeling and Optimization of Tribological Parameters of AA6061/SiC/B4C Hybrid Nano Composites
Authors: Das Shubhajit , Tamang Santosh  K. , Chandrasekaran Muthumari , Samanta Sutanu
Published: May 2019

The present work investigates the tribological properties of AA6061/1.5 wt.% SiC/1.5 wt.% B4C hybrid nanocomposites prepared using stir casting technique. The effect of sliding distance, sliding speed and load were investigated on wear rate (WR) and coefficient of friction (COF). Response surface methodology was used to predict and model the responses. Analysis of variance showed that sliding speed and load were the significant factor affecting WR and COF respectively. Desirability analysis was performed for both single and multi-objective optimization. The minimum WR and COF were found to be 0.0015 mm3/m and 0.2430 at sliding distance of 1939.39 m, sliding speed of 1.99 m/s and load of 10 N.
Willingness to Pay for Fruit Attributes: A Conjoint Analysis
Authors: Ranasingha R.G.S.M. , Edirisinghe Jagath C. , Ratnayake R.H.M.K.
Published: May 2019

Purpose: Identification of consumer preferences is important in designing products. Producers will immensely benefit by knowing them to capture the market share. In light of this, we evaluate consumers’ stated preferences for various attributes of four popular fruits: grapes, sweet orange, pear and pomegranate. Research Method: We run a Rank Ordered Logistic Regression (ROLOGIT) and calculate Willingness to Pay (WTP) for fruit attributes. Findings: We find that the perception of the fruits selected is contingent upon only a handful of attributes. We find that crispness and price are significant attributes in Pear. Price has a non-significant effect on preferences for grapes. Sweetness, shelf life and price significantly influence consumer choice when buying sweet oranges. Seeds that are relatively low in bitterness and softness are the two key attributes influencing the purchase decisions of Pomegranate. Research Limitations: The number of attributes used in the choice card was limited to most important attributes. Additionally, only a main effect model was estimated without considering the interaction effects of attributes in this study. Originality/ Value: Favorable features of fruits in Sri Lankan condition has not been studied so far. Thus, incorporating favorable features of the fruits considered into breeding programs of the local counterparts of these fruits may be fruitful.
Assessing the Likely Impacts of Proposed Food Boxes on SNAP Recipients
Authors: Ananouko Ahoefa
Published: May 2019

The Supplemental Nutrition Assistance Program (SNAP), formerly known as the Food Stamp Program, is the largest of the federal food and nutrition assistance programs. Studies show that SNAP is vital in increasing recipients’ food budgets, as reflected in recipients’ food spending before and after the 2009 Stimulus Package. SNAP has also been shown to reduce food insecurity for U.S. households. Proposed changes to SNAP by the Trump administration in its initial 2019 budget request could have major impacts on households that depend on the program to lessen the setbacks caused by poverty. Based on economic theory and results from previous studies examining expenditure responses to changes in SNAP, this article explores possible impacts of allocating half of SNAP benefits in the form of food boxes. It argues that these changes would have a negative impact on low-income households—especially children. These changes could create further food insecurity among some of the most vulnerable, while also increasing costs to the government.
Return on What Investment? The Behavioral Economics of Student Financial Aid
Authors: Hopkin McCall Pitcher
Published: May 2019

Each year, the federal government offers billions of dollars in need-based grant aid and loan subsidies to low-income college students. Concern is growing, however, around several system-wide problems that persist despite these federal investments: that many low-income students either 1) fail to take advantage of available aid; 2) are accepted to college but do not enroll; or 3) enroll but end up dropping out before graduating. While each of these decisions is informed by many factors, economists have identified program complexity and student behavioral bias as key variables—in other words, real humans do not always make the rational financial calculations policymakers expect of them when designing aid programs. This article reviews existing research on behavioral economics and student financial aid, examines access and completion barriers through a behavioral lens, and evaluates policy vehicles aimed to reverse students’ behavioral biases.