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Publicatii proprii

The influence of annealing treatments on the properties of Ag:TiO2

The present paper reports on the preparation and characterization of DC reactive magnetron sputtered Ag:TiO2 nanocomposite coatings, with a silver content of about 8 at.% (average estimation). The asdeposited samples were subjected to annealing, in a protective atmosphere, at temperatures ranging from 200 to 800 .C. Morphology, structure, hardness and friction behaviour were characterised after each heat treatment. The cross-sections of the films

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Dedifferentiation of Foetal CNS Stem Cells to Mesendoderm-Like Cells through an EMT Process

Tissue-specific stem cells are considered to have a limited differentiation potential. Recently, this notion was challenged by reports that showed a broader differentiation potential of neural stem cells, in vitro and in vivo, although the molecular mechanisms that regulate plasticity of neural stem cells are unknown. Here, we report that neural stem cells derived from mouse embryonic cortex respond to Lif and serum in vitro and undergo epithelial

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Un pod peste timp

Anghel Saligny magazine technical school

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Compatibility study between ketoprofen and pharmaceutical excipients used in solid dosage forms

Thermogravimetry/derivative thermogravimetry (TG/DTG) and differential scanning calorimetry (DSC) techniques were used for assessing the compatibility between ketoprofen (KT) and several excipients as: corn starch, microcrystalline cellulose (PH 101 and PH 102), colloidal silicon dioxide, lactose (monohydrate and anhydre), polyvinylpyrrolidone K30, magnesium stearate and talc, commonly used in the pharmaceutical form. In order to investigate the

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Properties of non powerful numbers

In this paper we study some properties of non powerful numbers. We evaluate the $n$-th non powerful number and prove for the sequence of non powerful numbers some theorems that are related to the sequence of primes: Landau, Mandl, Scherk. Related to the conjecture of Goldbach, we prove that every positive integer $ge3$ is the sum between a prime and a non powerful number.

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Simultaneouss Determination of Metals in Hypericum Perforatum L. by ICP-OES

The determination of macro and trace elements in Hypericum perforatum leaves and flowers was carried out by Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES) [1,2]. Samples of fourteen populations were collected from the wild flora of Bihor county. Plants taken from areas in Romania with different geographical features (mountains, lowlands, and wildwoods) are more or less exposed to pollution sources in this part of the country (waste

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Relating the Riemann Hypothesis and the primes between two cubes

In this paper we make an evaluation for the number of primes between two consecutive cubes, if we assume the Riemann hypothesis.

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SOME PROPERTIES OF THE SEQUENCE OF PRIME NUMBERS

Let $p_n$ be the $n$-th prime number and $x_n=p_{n+1}^{n+1}/p_n^n$. We show that the sequence $(x_n)_{nge 1}$ is not monotone and that the series $sumlimits_{n=1}^infty 1/x_n$ is divergent. Related series are studied as well.

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Kinetic Study of Decomposition of Ibuprofen under Isothermal Conditions

Thermal analysis is one of the most widely used methods for studying the solid state of pharmaceutical substances. The thermoanalytical curves provide important information regarding the physical properties of the pharmaceutical compounds (stability, compatibility, polymorphism, phase transition, kinetic analysis etc). The purpose of a kinetic investigation is to calculate the kinetic parameters and the kinetic model for the studied process. The

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ON THE RATIO OF CONSECUTIVE PRIMES

For $nge 1$ let $p_n$ be the $n$-th prime number and $q_n=frac{p_{n+1}}{p_n}$ for $nge 1$. Using several results of ErdH{o}s we study the sequence $(q_n)_{nge 1}$ and we prove similar results as for the sequence $(d_n)_{nge 1}$, $d_n=p_{n+1}-p_n$. We also consider the sequence $x_n=q_n^n$ for $nge 1$ and denote by $G_n$ and $A_n$ its geometrical and arithmetical averages. We prove that $1

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