Replacing the detector mask with a structured scintillator in edge-illumination x-ray phase contrast imaging

We present a proof-of-concept edge illumination x-ray phase contrast system where the detector mask has been replaced by an indirect conversion detector in which sensitive and insensitive regions have been obtained by “patterning” the scintillator. This was achieved by creating a free-standing grid with period and aperture size matching that of a typical detector mask and filling the apertures with gadolinium oxysulfide. Images of various samples were collected with both the modified and the original edge illumination systems based on the use of two masks to characterize the performances of this detector design. We found that, despite the proof-of-concept nature of this attempt resulting in a structured detector with suboptimal performance, it allows effective separation of the attenuation and refraction channels through phase retrieval and the visualization of hard-to-detect features such as cartilage through the latter channel, thus demonstrating that the proposed approach holds the potential to lead to improved stability since it will use a single optical element facilitating the design of rotating phase contrast systems or the retrofitting of conventional x-ray systems

Riboflavin Ameliorates Cisplatin Induced Toxicities under Photoillumination

BACKGROUND: Cisplatin is an effective anticancer drug that elicits many side effects mainly due to induction of oxidative and nitrosative stresses during prolonged chemotherapy. The severity of these side effects consequently restricts its clinical use under long term treatment. Riboflavin is an essential vitamin used in various metabolic redox reactions in the form of flavin adenine dinucleotide and flavin mononucleotide. Besides, it has excellent photosensitizing property that can be used to ameliorate these toxicities in mice under photodynamic therapy. METHODS AND FINDINGS: Riboflavin, cisplatin and their combinations were given to the separate groups of mice under photoilluminated condition under specific treatment regime. Their kidney and liver were excised for comet assay and histopathological studies. Furthermore, Fourier Transform Infrared Spectroscopy of riboflavin-cisplatin combination in vitro was also conducted to investigate any possible interaction between the two compounds. Their comet assay and histopathological examination revealed that riboflavin in combination with cisplatin was able to protect the tissues from cisplatin induced toxicities and damages. Moreover, Fourier Transform Infrared Spectroscopy analysis of the combination indicated a strong molecular interaction among their constituent groups that may be assigned for the protective effect of the combination in the treated animals. CONCLUSION: Inclusion of riboflavin diminishes cisplatin induced toxicities which may possibly make the cisplatin-riboflavin combination, an effective treatment strategy under chemoradiotherapy in pronouncing its antineoplastic activity and sensitivity towards the cancer cells as compared to cisplatin alone

Degradación y mineralización de tartrazina mediante electrooxidación. Optimización de las condiciones de operación

In this work, the operational conditions of the tartrazine electro-oxidation (EO) process were optimized. The batch reactor used has two electrodes: one made of diamond doped with boron and the other one of titanium, working at monopolar configuration. The initial dyestuff concentration (Ci), the current density (i) and the pH were defined as the main factors affecting the EO. Their optimal values were found as follows: Ci=30 ppm, i=5mA/cm2 and pH=6.0. At these conditions, a kinetic analysis was performed in the terms of: the percentage of the dyestuff decolorization (%DC), the percentage of the chemical oxygen demand (%DCOD), and the percentage of the total organic carbon (%TOC). Additionally, the effect of Fe2+ (electro- Fenton process, EF) and Fe2+/UV radiation (electro-photo-Fenton process, EFF) on the studied process were evaluated. The work demonstrates the validity of the hypothesis about the most significant parameters that affect the EO process

Región de Inestabilidad y Optimización de las Condiciones de Producción de Metanol en un Reactor Lurgi

In the present work, the operational conditions for methanol synthesis in a Lurgi reactor are analyzed. The industrial data for a packed reactor (consisting of 1620 tubes of 7 m long) are the basis of this study. At first, the industrial reactor is simulated achieving excellent agreement with plant data. Then, the instability region is defined as a boundary in the conversion-temperature diagram and defines the conditions that must be avoided during reactor operation. The optimization of the operational conditions is performed based on the optimal temperature progression from the iso-reaction rate curves. Finally, it was found that the cooling fluid must be at 230 °C and that the heat transfer coefficient must guarantee a value of 118 J/(s.K.m2)

Degradación de Colorante Amarillo 12 de Aguas Residuales Industriales utilizando Hierro Cero Valente, Peróxido de Hidrógeno y Radiación Ultravioleta

The Fenton heterogeneous process in a fluidized bed reactor using Zero Valent Iron (ZVI), in the metallic state, for the treatment of textile wastewater has been used an analyzed. The aim of this work was to optimize the following operating parameters: initial dye concentration, H2O2 concentration, pH, amount of ZVI, and UV radiation, for the removal of dye and organic matter. At first, a fractional factorial experimental design allows defining the most influential factors. After that, they were optimized using the Response Surface Methodology coupled to the Box-Behnken experimental design. The optimal conditions were found to be as follows: initial dye concentration, 881 mg/L; pH 5; ZVI concentration, 5,31 g/L; H2O2 concentration, 0,86 mL/L. At these conditions, the degradation kinetics was performed, reaching 100% and 80,83% of dye and chemical oxygen demand respectively, in 150 minutes of reaction

Sensibilidad Paramétrica y Condiciones Seguras de Operación de la Hidrólisis del Anhídrido Acético en un Reactor Batch

The results of a study on the parametric sensitivity of acetic acid production by hydrolysis of acetic anhydride, using acid homogeneous catalysis in a batch reactor, are presented. Dimensionless parameters of mass and energy balances were fitted using experimental data available in the literature that includes the variation of the reaction temperature for different sulfuric acid concentrations (3% to 5%). Then, from the analysis of the intrinsic mathematical properties of the concentration-temperature phase plane, the critical operating conditions were defined. Thus, it was possible to determine the specific values of the safe operating conditions for the catalyzed hydrolysis of acetic anhydride, in the function of catalyst concentration

The removal of the trivalent chromium from the leather tannery wastewater: the optimisation of the electro-coagulation process parameters.

The capacity of the electro-coagulation (EC) process for the treatment of the wastewater containing Cr3+, resulting from a leather tannery industry placed in Medellin (Colombia), was evaluated. In order to assess the effect of some parameters, such as: the electrode type (Al and/or Fe), the distance between electrodes, the current density, the stirring velocity, and the initial Cr3+ concentration on its efficiency of removal (%RCr+3), a multifactorial experimental design was used. The %RCr3+ was defined as the response variable for the statistical analysis. In order to optimise the operational values for the chosen parameters, the response surface method (RSM) was applied. Additionally, the Biological Oxygen Demand (BOD5), the Chemical Oxygen Demand (COD), and the Total Organic Carbon (TOC) were monitored during the EC process. The electrodes made of aluminium appeared to be the most effective in the chromium removal from the wastewater under study. At pH equal to 4.52 and at 28 degrees C, the optimal conditions of Cr3+ removal using the EC process were found, as follows: the initial Cr3+ concentration=3,596 mg/L, the electrode gap=0.5 cm, the stirring velocity=382.3 rpm, and the current density=57.87 mA/cm2. At those conditions, it was possible to reach 99.76% of Cr3+ removal, and 64% and 61% of mineralisation (TOC) and COD removal, respectively. A kinetic analysis was performed in order to verify the response capacity of the EC process at optimised parameter values

Instability Analysis and Optimal Conditions for Methanol Production in a Lurgi Reactor.

In the present work, the operational conditions for methanol synthesis in a Lurgi reactor are analyzed. The industrial data for a packed reactor (consisting of 1620 tubes of 7 m long) are the basis of this study. At first, the industrial reactor..