A statistical model for unwarping of 1-D electrophoresis gels

A statistical model is proposed which relates density profiles in 1-D electrophoresis gels, such as those produced by pulsed-field gel electrophoresis (PFGE), to databases of profiles of known genotypes. The warp in each gel lane is described by a trend that is linear in its parameters plus a first-order autoregressive process, and density differences are modelled by a mixture of two normal distributions. Maximum likelihood estimates are computed efficiently by a recursive algorithm that alternates between dynamic time warping to align individual lanes and generalised-least-squares regression to ensure that the warp is smooth between lanes. The method, illustrated using PFGE of Escherichia coli O157 strains, automatically unwarps and classifies gel lanes, and facilitates manual identification of new genotypes.     

A simple route for the synthesis of 3,3,3′,3′-tetramethyl-2,3,3′,4′-tetrahydro-1H,1′H-[4,9′-bixanthene]-1,1′(2′H,9′H)-dione and its derivatives catalyzed by Mn and other transition metal cations

A simple and efficient unusual coupling reaction of 9-(2-hydroxy-4,4-dimethyl-6-oxocyclohex-1-en-1-yl)-3,3-dimethyl-2,3,4,9-tetrahydro-1H-xanthen-1-one and its derivatives was accomplished in the presence of Mn²⁺, Cu²⁺, Cd²⁺, Hg²⁺, Fe³, or La³⁺. The structure elucidation was accomplished by IR, ¹H NMR, ¹³C NMR, X-ray crystallography, UV-Visible and elemental analysis. A reaction mechanism is proposed.     

Influence of surface topography and annealing temperature on the surface and volume of dissipation electrical energy and Spitzer–Fan model in Al doped ZnO films

The aim of this work is to investigate the optical constants of aluminum doped zinc oxide films annealed at different temperatures. With increasing temperature, due to decreasing unfilled inter-granular volume per unit thickness, the optical transmittance spectra of films were increased. The films have a normal dispersion in the spectral range 400?<?λ?<?500 nm and the anomalous dispersion in IR range. The lattice dielectric constants ε_L, the free charge carriers concentration, the plasma frequency, Spitzer–Fan model and the waste of electrical energy as heat of films can be analyzed using the refractive index n and the extinction coefficient k spectra. With increasing annealing temperature, the lattice dielectric constants ε_L of films decrease however the free charge carriers concentration of films increase. The free carrier electric susceptibility of films annealed at 600 °C has maximum value. The energy loss by the free charge carriers when traversing the bulk and surface of films annealed at 600 °C has a minimum value in the near fundamental absorption edge and it with increasing energy increases.     

Quality by Design: Design of Experiments Approach Prior to the Validation of a Stability-Indicating HPLC Method for Montelukast

This paper describes a systematic design of experiments (DoE) approach by applying the principle of quality by design (QbD) to determine the design space for a stability-indicating HPLC method prior to validation. By employing DoE, a simultaneous multivariate approach was carried out for mobile phase pH, flow rate, percentage of organic content and column temperature. A two-level fractional factorial design (2⁴⁻¹ + 2 center points = 10 experiments) was employed and statistical analysis of the experimental data uncovered the significant influential chromatographic factors. The experimental data for USP tailing and resolution were analyzed statistically to screen the chromatographic factors. This approach determined the most influential chromatographic factors. During this process, inferences were evaluated from various data tables, for example, analysis of variance, summary of fit, lack of fit, and parameter estimates. The study also explained various plots such as actual vs. predicted plot, Pareto plot, and prediction profiler. The acceptable range of the chromatographic factors was displayed as a Contour plot defining the ‘design space’ of the method. The range of operating conditions that guarantee a satisfactory QbD was deduced to finalize the method prior to validation. The method is simple, rapid, and robust for the determination of montelukast in montelukast sodium oral granules dosage form. The method was validated according to ICH guidelines for accuracy, precision, linearity, range, specificity, ruggedness and robustness (one factor varied at a time). The method has been successfully transferred to the quality control department for quality analysis of manufactured batches and stability samples.

     

A nano-fibrillated mesoporous carbon as an effective support for palladium nanoparticles in the aerobic oxidation of alcohols "on pure water"

A novel nano-fibrillated mesoporous carbon (IFMC) was successfully prepared via carbonization of the ionic liquid 1-methyl-3-phenethyl-1H-imidazolium hydrogen sulfate (1) in the presence of SBA-15. The material was shown to be an efficient and unique support for the palladium nanoparticle (PdNP) catalyst Pd@IFMC (2) in aerobic oxidation of heterocyclic, benzylic, and heteroatom containing alcohols on pure water at temperatures as low as 40 °C for the first time and giving almost consistent activities and selectivities within more than six reaction runs. The catalyst has also been employed as an effective catalyst for the selective oxidation of aliphatic and allylic alcohols at 70-80 °C. The materials were characterized by X-ray photoelectron spectroscopy (XPS), N(2) adsorption-desorption analysis, transmission electron microscopy (TEM), and electron tomography (ET). Our compelling XPS and ET studies showed that higher activity of 2 compared to Pd@CMK-3 and Pd/C in the aerobic oxidation of alcohols on water might be due to the presence of nitrogen functionalities inside the carbon structure and also the fibrous nature of our materials. The presence of a nitrogen heteroatom in the carboneous framework might also be responsible for the relatively uniform and nearly atomic-scale distribution of PdNPs throughout the mesoporous structure and the inhibition of Pd agglomeration during the reaction, resulting in high durability, high stability, and recycling characteristics of 2. This effect was clearly confirmed by comparing the TEM images of the recovered 2 and Pd@CMK-3.     

Identification of Voice Disorders Using Long-Time Features and Support Vector Machine With Different Feature Reduction Methods

Identification of voice disorders has a fundamental role in our life nowadays. Therefore, many of these diseases must be diagnosed at early stages of occurrence before they lead to a critical condition. Acoustic analysis can be used to identify voice disorders as a complementary technique with other traditional invasive methods, such as laryngoscopy. In this article, we followed an extensive study in the diagnosis of voice disorders using the statistical pattern recognition techniques. Finally, we proposed a combined scheme of feature reduction methods followed by pattern recognition methods to classify voice disorders. Six classifiers are used to evaluate feature vectors obtained by principal component analysis or linear discriminant analysis (LDA) as feature reduction methods. Furthermore, individual, forward, backward, and branch-and-bound methods are examined as feature selection methods. The performance of each combined scheme is evaluated in terms of the accuracy, sensitivity, specificity, and area under the receiver operating characteristic curve (AUC). The experimental results denote that LDA along with support vector machine (SVM) has the best performance, with a recognition rate of 94.26% and AUC of 97.94%. Additionally, this structure has the lowest complexity in comparison with other architectures. Among feature selection methods, individual feature selection followed by SVM classifier shows the best recognition rate of 91.55% and AUC of 95.80%.     

Synthesis of α-phthalimido-α′-dithiocarbamato propan-2-ols via a one-pot,three-component epoxide ring-opening in water

Regioselective ring-opening of the N-(2,3-epoxypropyl)phthalimide with in situ prepared dithiocarbamic acid in water is reported for the synthesis of a new family of α-phthalimido-α′-dithiocarbamato propan-2-ols. The present method is simple, EtOAc is used for work-ups and affords excellent yield of products.     

Disposable amperometric sensor for neurotransmitters based on screen-printed electrodes modified with a thin iridium oxide film.

Potential cycling in the range from -0.2 to +1.2 V is used for the electrodeposition of hydrous iridium oxide films onto a screen-printed electrode from a saturated solution of alkaline iridium(III) solution. The iridium oxide redox couple shows a stable and obvious reversible redox, with the formal potential being pH dependent in the range 1-14. The properties, stability and electrochemical properties of iridium oxide films were investigated by cyclic voltammetry. A modified electrode showed excellent catalytic activity toward the oxidation of neurotransmitters (catecholamines) over a wide pH range (2-8). The electrocatalytic behavior is further exploited as a sensitive detection scheme for adrenaline and dopamine by hydrodynamic amperometry. Under the optimized conditions, the calibration curves are linear in the concentration range 0.1-70 and 0.1-15 microM for dopamine and adrenaline determination, respectively. The detection limit and sensitivity are 30 nM and 30 nA/microM for adrenaline and 15 nM and 80 nA/microM for dopamine. Finally, the analytical performance of the modified electrode was demonstrated for the elimination of interference by uric acid in catecholamines determination when present in a 1000-fold concentration excess.     

Asymptotic Maslov’s method for shocks of conservation laws systems with quadratic flux

In this work we apply the asymptotic method suggested by Maslov [1] to obtain the Hugoniot–Maslov chain for shock type solutions of conservation laws systems with quadratic flux. Additionally to the ODE infinite system that make up the chain, it was obtained an algebraic compatibility condition that must be satisfied by some of the coefficients of the asymptotic expansion of the shock solution. We give a new geometrical interpretation for this compatibility condition by means of certain singular surface whose projections represent time-dependent Hugoniot locus through the left limit state of the Shock.