The number of self-dual codes over $${Z_{p^3}}$$

Let p be a prime number. In this paper, we consider codes over the ring of integers modulo p ³ and give a characterization of self-duality. This leads to a construction of self-dual codes and a mass formula, which counts the number of such codes over .      

LC–MS/MS Method for the Simultaneous Determination of Free Urinary Steroids

Cortisol homeostasis is implicated in hypertension and metabolic syndrome. Two enzymes modulate cortisol availability; 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) preferentially converts inactive cortisone to cortisol, whereas 11β-hydroxysteroid dehydrogenase type 2 (11β-HSD2) converts cortisol to cortisone. In contrast, 5α and 5β reductases inactivate cortisol by conversion to its tetrahydrometabolites: tetrahydrocortisol, allo-tetrahydrocortisol and tetrahydrocortisone. A subtle local increase in cortisol can be detected by measuring 24-h urine metabolites, LC–MS/MS being the reference method. The 11β-HSD2 activity is assessed based on the cortisol/cortisone ratio, and the 11β-HSD1 activity on the (tetrahydrocortisol + allo-tetrahydrocortisol)/tetrahydrocortisone ratio. To better understand hypertension and/or metabolic syndrome pathogenesis a method for simultaneous determination of cortisol, cortisone, tetrahydrocortisol, allo-tetrahydrocortisol and tetrahydrocortisone was developed and validated in an LC coupled with the new detector AB Sciex QTrap^® 4500 tandem mass spectrometer. The steroids were extracted from 1 mL urine, using cortisol-D4 as internal standard. The quantification range was 0.1–120 ng/mL for cortisol and cortisone, and 1–120 ng/mL for tetrahydrometabolites, with >89 % recovery for all analytes. The coefficient of variation and accuracy was <10 %, and 85–105 %, respectively. Our LC–MS/MS method is accurate and reproducible in accordance with Food and Drug Administration guidelines, showing good sensitivity and recovery. This method allows the assessment of 11β-HSD2 and 11β-HSD1 activities in a single analytical run providing an innovative tool to explain etiology of misclassified essential hypertension and/or metabolic syndrome.     

Surface nitriding of Ti–6Al–4V alloy with a high power CO2 laser

Surface nitriding of a Ti–6Al–4V alloy by laser melting in a flow of nitrogen gas has been investigated, with the aim of increasing surface hardness and hence improving related properties such as wear and erosion resistance. The effect of the scanning speed, nitrogen dilution, and nitrogen flow rate on microstructure, microhardness, and cracking of the nitrided layers was studied. Optical, scanning electron microscopy, energy dispersive spectroscopy, and X-ray diffraction (XRD) were used to reveal the microstructure and to identify the phases formed. It is shown that smooth, deep, and crack-free nitride layers of a surface hardness ranging between 500 and 800 HV can be obtained by controlling the processing parameters. Cracks are present in the sample processed at slow scanning speed and high laser power. Dilution of the nitrogen gas with argon gas leads to a crack-free nitride layer at the expense of a reduction in surface hardness. Slow scanning speeds lead to the formation of a deep and hard surface layer, and increasing the nitrogen flow rate results in a rough surface with a slight increase in hardness.     

A Multiple Multicomponent Approach to Chimeric Peptide–Peptoid Podands

The success of multi‐armed, peptide‐based receptors in supramolecular chemistry traditionally is not only based on the sequence but equally on an appropriate positioning of various peptidic chains to create a multivalent array of binding elements. As a faster, more versatile and alternative access toward (pseudo)peptidic receptors, a new approach based on multiple Ugi four‐component reactions (Ugi‐4CR) is proposed as a means of simultaneously incorporating several binding and catalytic elements into organizing scaffolds. By employing α‐amino acids either as the amino or acid components of the Ugi‐4CRs, this multiple multicomponent process allows for the one‐pot assembly of podands bearing chimeric peptide–peptoid chains as appended arms. Tripodal, bowl‐shaped, and concave polyfunctional skeletons are employed as topologically varied platforms for positioning the multiple peptidic chains formed by Ugi‐4CRs. In a similar approach, steroidal building blocks with several axially‐oriented isocyano groups are synthesized and utilized to align the chimeric chains with conformational constrains, thus providing an alternative to the classical peptido‐steroidal receptors. The branched and hybrid peptide–peptoid appendages allow new possibilities for both rational design and combinatorial production of synthetic receptors. The concept is also expandable to other multicomponent reactions.     

Passive decomposition and gradient control of fractional-order nonlinear systems

Nonlinear Dynamics - Vector field decomposition is essential in physics and engineering in order to analyze several dynamical systems that appear in these areas. This paper proposes some novel...     

Mass formula and structure of self-dual codes over {{\bf Z}_{2^s}}

We look at the structure of and give a mass formula for self-dual codes over the ring ${{\bf Z}_{2^s}}$ of integers modulo 2 ^s . Together with earlier work on the case of odd primes, this completes the mass formula for self-dual codes for ${{\bf Z}_{p^s}}$ , for all prime numbers p and positive integers s.     

Predefined-time control of distributed-order systems

Nonlinear Dynamics - Distributed-order calculus can be understood as a further generalisation of integer- and fractional-order calculus. Such a general case allows the modelling and understanding...     

Sonophotocatalytic degradation of congo red and methyl orange in the presence of TiO2 as a catalyst

A comparative study between the photocatalytic and sonophotocatalytic oxidation process of congo red was carried out using titanium dioxide as a catalyst. The effect of a number of parameters, such as the initial concentration of dye, the presence of oxygen and ultrasound, the TiO(2) crystalline structure and the amount of TiO(2), was studied using an inexpensive reactor. In the second part of this document, the oxidation and reduction processes of methyl orange was studied using the same reactor, but by changing the chemical environment in order to drive either the oxidation or the reduction reaction. The results showed, for all the cases studied, a sinergistic effect between sonolysis and photocatalysis when an ultrasonic bath of 80W was used as a source of ultrasound. On the other hand, the electrochemical experiments showed that the current densities for the oxidation process of the azodyes were higher when a conducting glass electrode covered with a thin film of TiO(2) was used as a working electrode instead of a platinum electrode, showing that the TiO(2) electrode is not passivated by the oxidation reaction.     

Polycaprolactone and poly-β-cyclodextrin polymer blend: a Biopolymers composite film for drug release

Nowadays, biomedical films containing drug carriers are preferred over conventional ones, since the protection of the injury and the therapy is joined within a single device. In the current work, we prepared polycaprolactone (PCL) composite films with β-cyclodextrin (βCD) or its epichlorohydrin crosslinked polymer (βCDP) as ibuprofen (Ibu) drug carrier. The composite films were prepared at different PCL/additive ratios (2, 5, 10 and 20 wt%). ATR-FTIR spectroscopy and water contact angle (WCA) measurements indicated a scarce presence of the additives on the surface. Cross-section scanning electron micrographs showed the presence of aggregates corresponding to βCD and βCDP in the inner regions of the films. The incorporation of βCD and βCDP into the PCL films did not affect their thermal properties as was determined from differential scanning calorimetry (DSC). PCL-films with 10 wt% of the inclusion complexes Ibu@βCD and Ibu@βCDP were prepared and the release studies were performed. At pH?=?7.2, PCL-Ibu@βCDP composite film released 55% of Ibu within the first six hours; eight times the amount released by PCL-Ibu@βCD within the same time interval. A plausible mechanism for ibuprofen release is discussed based on the cross-section SEM micrographs of composite films.

     

Isolation and characterization of modified species of a mutated (Cys125 -Ala) recombinant human interleukin-2

An approach for simultaneous determination of the main type A-trichothecenes by liquid chromatography and atmospheric pressure chemical ionization mass spectrometry is described. Parameters for coupling of LC-MS such as cone voltage, nebulizing temperature and the LC flow-rate, were optimized to provide detection of mycotoxins with maximum sensitivity. Furthermore, the effects of cone voltage and temperature on the fragmentation pattern of the tested toxins were studied. Main type A-trichothecenes such as T-2 Toxin, HT-2 Toxin, acetyl T-2 Toxin, diacetoxyscirpenol, monoacetoxyscirpenol (15-acetoxyscirpenol) and neosolaniol were separated on a reversed-phase narrow bore C18 column, using a linear gradient and a flow-rate of 0.3 ml/min. Mass spectra were obtained in positive ion mode for confirmation and quantitation. The method involves extraction and purification of toxins by using multifunctional Mycosep columns. Deuterated T-2 Toxin was used as an internal standard. A linear working range between 80 and 500 microg/kg in matrix with an acceptable correlation coefficient was observed. The developed method was validated by using a blank oats sample. The detection limit in the matrix was found to be between 50 and 85 microg/kg in selected ion mode for all tested A-trichothecenes. Recovery data were found to be between 77 and 101%. Within run and day-to-day precision were determined as having comparable levels to those found using GC methods. Furthermore, the matrix effect was investigated by comparing the internal standard versus the external standard method in quantification studies. In addition, the developed method was applied for the analysis of naturally contaminated oats, maize, barley and wheat samples.