Slow magnetic dynamics and hysteresis loops of a bulk ferromagnet

Magnetic dynamics of a bulk ferromagnet, a new single crystalline compound Co7(TeO3)4Br6, was studied by ac susceptibility and the related techniques. Very large Arrhenius activation energy of 17.2 meV (201 K) and long attempt time (2x10^(-4)s) span the full spectrum of magnetic dynamics inside a convenient frequency window, offering a rare opportunity for general studies of magnetic dynamics. Within the experimental window the ac susceptibility data build almost ideally semicircular Cole-Cole plots. Comprehensive study of experimental dynamic hysteresis loops of the compound is presented and interpreted within a simple thermal-activation-assisted spin lattice relaxation model for spin reversal. Quantitative agreement between the experimental results and the model's prediction for dynamic coercive field is achieved by assuming the central physical quantity, the Debye relaxation rate, to depend on frequency, as well as on the applied field strength and sample temperature. Cross-over between minor- to major hysteresis loops is carefully analyzed. Low-frequency limitations of the model, relying on domain wall pinning effects, are experimentally detected and appropriately discussed.Comment: A paragraph on dynamical-hysteresis assymetry added, text partially revised; Accepted in Physical Review

Two component butterfly hysteresis in Ru1222 ruthenocuprate

We report detailed studies of the ac susceptibility butterfly hysteresis on the Ru1222 ruthenocuprate compounds. Two separate contributions to these hysteresis have been identified and studied. One contribution is ferromagnetic-like and is characterized by the coercive field maximum. Another contribution, represented by the so called inverted maximum, is related to the unusual inverted loops, unique feature of Ru1222 butterfly hysteresis. The different nature of the two identified magnetic contributions is proved by the different temperature dependences involved. By lowering the temperature the inverted peak gradually disappears while the coercive field slowly raises. If the maximum dc field for the hysteresis is increased, the size of the inverted part of the butterfly hysteresis monotonously grows while the position of the peak saturates. In reaching saturation exponential field dependence has been demonstrated to take place. At T = 78 K the saturation field is 42 Oe.Comment: 5 pages, 5 figure

Ground state order and spin-lattice coupling in tetrahedral spin systems Cu2Te2O5X2

High-resolution ac susceptibility and thermal conductivity measurement on Cu2Te2O5X2(X=Br,Cl) single crystals are reported. For Br-sample, sample dependence prevents to distinguish between possibilities of magnetically ordered and spin-singlet ground states. In Cl-sample a three-dimensional transition at 18.5 K is accompanied by almost isotropic behavior of susceptibility and almost switching behavior of thermal conductivity. Thermal conductivity studies suggest the presence of a tremendous spin-lattice coupling characterizing Cl- but not Br-sample. Below the transition Cl-sample is in a complex magnetic state involving AF order but also the elements consistent with the presence of a gap in the excitation spectrum.Comment: version accepted for publication in Phys.Rev.B-Rapid Communicatio

The Content of Coumarin in the Commercial Samples of Cinnamon Bark and Cinnamon-Containing Dietary Supplements Available on the Serbian Market

Cinnamon bark is used worldwide due to its characteristic flavour and medicinal properties. Ceylon cinnamon or “true” cinnamon bark refers to the dried inner bark of the shoots of Cinnamomum verum J. Presl, originated from Sri Lanka. The bark of some other species of this genus, Cinnamomum cassia Blume (Chinese cinnamon), C. burmanni (Nees & T. Nees) Blume (Indonesian cinnamon), and C. loureiroi Nees (Saigon cinnamon) are also marketed and sold as cinnamon. They are characterised by a significantly higher amount of coumarin compared to Ceylon cinnamon bark. Since coumarin may be potentially hepatotoxic, the aim of this study was to determine coumarin level in commercial samples of cinnamon bark and in cinnamon-containing dietary supplements present on the Serbian market. HPLC analysis showed lowest coumarin content in Ceylon cinnamon bark samples (0.08–0.15 mg g–1), whereas other samples contained a significantly higher amounts of coumarin (1.38–5.80 mg g–1). Cinnamon based dietary supplements contained 0.007-1.19 mg coumarin/tablet. The obtained results indicate that the majority of commercial samples of cinnamon bark on the Serbian market do not originate from the Ceylon cinnamon but from other species of this genus, and that consumed amount of certain products should be taken into account since the tolerable daily intake of coumarin is limited

TSH-CHECK-1 test: diagnostic accuracy and potential application to initiating treatment for hypothyroidism in patients on anti-tuberculosis drugs.

Thyroid-stimulating hormone (TSH) promotes expression of thyroid hormones which are essential for metabolism, growth, and development. Second-line drugs to treat tuberculosis (TB) can cause hypothyroidism by suppressing thyroid hormone synthesis. Therefore, TSH levels are routinely measured in TB patients receiving second-line drugs, and thyroxin treatment is initiated where indicated. However, standard TSH tests are technically demanding for many low-resource settings where TB is prevalent; a simple and inexpensive test is urgently needed

Building a Web marketing experience: the Maltese case of Where's Everybody

L’attività di web marketing, concepita fino ad oggi come esclusiva dell’impresa, sta vivendo un’evoluzione in senso sociale e partecipativo che dipende dall’evoluzione stessa del Web. Quello che in particolare si modifica non è lo scopo, che rimane sempre la soddisfazione del cliente e la sua fidelizzazione, ma l’avere a disposizione di utilizzo una “cassetta degli strumenti” più ampia e malleabile. Partendo dalla considerazione di questo fatto, la scelta dell’argomento del presente lavoro di ricerca è avvenuta in seguito a un’esperienza lavorativa di tre mesi presso il Dipartimento di Marketing & Public Relation di Where’s Everybody, una delle maggiori aziende di produzione televisiva a Malta. Questa opportunità mi è stata offerta grazie a una borsa di studio del Progetto Leonardo. Alla luce di questa prospettiva, si è cercato innanzitutto di fornire un’accurata analisi delle variabili del macro-ambiente che rendono Malta un caso particolare in Europa, sia economico, politico che sociale e culturale. In seguito si è definito il micro-ambiente, ovvero il panorama televisivo locale e la concorrenza, con particolare attenzione alla descrizione e al target dei programmi di Where’s Everybody. Il capitolo successivo è dedicato a come il Web 2.0 sta modificando gli assi portanti dell’attività di marketing, e in generale al marketing 2.0. In particolare, saranno delineate le principali caratteristiche del web marketing, non tutte ma soltanto quelle relative al lavoro svolto e all’azienda presa in considerazione. Queste sono: lo spostamento di valore dalla transazione alla relazione; il paradigma di comunicazione many-to-many e i suoi elementi fondanti (comunità virtuale, user-generated content e passaparola); l’empowerment del consumatore e il cambiamento della definizione del marketing mix. Queste considerazioni vengono applicate nella seconda parte del lavoro, in cui vengono analizzati gli strumenti e le applicazioni di web marketing utilizzati dall’azienda maltese, prima, dopo e durante il mio periodo di lavoro. Essi sono analizzati per siti Internet, social networks e servizi streaming e on-demand. In particolare, l’analisi dei punti di forza e di debolezza dell’impiego di questi strumenti serve come spunto per presentare suggerimenti di miglioramento per la strategia complessiva, in accordo con i concetti chiave del Web 2.0, ovvero collaborazione e partecipazione degli utenti. Con ciò si dimostra che Where’s Everybody ha saputo cogliere le opportunità di evoluzione del marketing in un’ottica 2.0, comprovate dai dati forniti dall’Authority delle Comunicazioni e dalle indagini di mercato svolte dalla Media Warehouse di Malta. Lo scopo finale è quindi quello di fornire, in prima istanza, una mappatura generale dello scenario di cambiamento del Web 2.0 e conseguentemente dell’attività di marketing. In seconda istanza, preso il caso pratico di una casa di produzione televisiva non italiana, il presente lavoro si propone di offrire un esempio di azienda capace di sfruttare al meglio le effettive potenzialità dei nuovi strumenti di web marketing, sottolineando le strategie adottate e l’abilità di creare valore aggiunto per i suoi clienti

Ruthenocuprates RuSr2(Eu,Ce)2Cu2O10: Intrinsic magnetic multilayers

We report ac susceptibility data on RuSr_2(Eu,Ce)_2Cu_2O_(10-y) (Ru-1222, Ce content x=0.5 and 1.0), RuSr_2GdCu_2O_8 (Ru-1212) and SrRuO_3. Both Ru-1222 (x=0.5, 1.0) sample types exhibit unexpected magnetic dynamics in low magnetic fields: logarithmic time relaxation, switching behavior, and `inverted' hysteresis loops. Neither Ru-1212 nor SrRuO_3 exhibit such magnetic dynamics. The results are interpreted as evidence of the complex magnetic order in Ru-1222. We propose a specific multilayer model to explain the data, and note that superconductivity in the ruthenocuprate is compatible with both the presence and absence of the magnetic dynamics.Comment: 9 pages, 11 figures, Revtex; submitted to Phys.Rev.

Improving OCR of historical newspapers and journals published in Finland

Peer reviewe

Polyphenol rich extracts of Geranium L. species as potential natural antioxidant and antimicrobial agents

OBJECTIVE: Plants and plant extracts are of great scientific interest due to the chemical diversity and pharmacological properties of present bioactive molecules. The Geranium L. species are widely used in ethnomedicine. In the current study, the total phenolic and tannin content, antioxidant and antimicrobial activity of methanol extracts of eight Geranium species were investigated. MATERIALS AND METHODS: The total phenolic and tannin content were determined by the FC method. Antioxidant capacity was evaluated in FRAP, DPPH, and biochemical assays, while antimicrobial activity was examined using the broth microdilution method. RESULTS: The high total phenolic (170.64- 636.32 mg GAE/g dry extract) and tannin content (37.80-414.02 mg GAE/g DE), along with significant total antioxidant (FRAP values 1.13-8.80 mmol Fe2+/g) and DPPH radical scavenging activity (SC50 values 4.24-34.52 µg/mL) were observed. The prominent antioxidant capacity was confirmed in biochemical assays (OS values -1.47 – -13.02). The extracts exhibited significant antimicrobial activity against ATTC strains (MICs dominantly in the range of 12.5-200 µg/mL) as well as against clinical isolates of E. coli (MICs mostly 50 and 100 µg/mL). The pronounced antioxidant and antimicrobial activity can be due to the high phenolic content, particularly due to the presence of hydrolyzable tannins. CONCLUSIONS: Based on the high content of polyphenols, pronounced antioxidant and antimicrobial activities, the examined extracts are promising natural antioxidant and antimicrobial agents with the potential medicinal purpose and use as a functional food