Study of anaesthetical activity of alkoxyphenylcarbamic acid esters using statistical methods

Anaesthetical activity of 113 morpholinoethyl-, piperidinoethyl-, piperidinopropyl- and azepanoethyl- ester derivatives of alkoxyphenylcarbamic acid was characterized by several chemometrical techniques. The surface anaesthetical activity, A, and the infiltration anaesthetical activity, B, were correlated to lipophilicity, (expressed by the logarithm of the HPLC retention factor, log k), the length of the side alkoxy chain (represented by the number n of carbon atoms), molar mass M as well as the ester type. Principal component analysis and cluster analysis were used for predicting both types of the anaesthetic activity of the alkoxyphenylcarbamic acid esters.

Thermal Characteristic of Tetraselmis chuii Combustion Influenced by Titanium Dioxide (TiO2) Nanoparticle

The investigation of Titanium dioxide (TiO2) nanoparticles on the thermal characteristic of Tetraselmis chuii (T.Chuii) microalgae during combustion process has been carried out through a thermogravimetric (TG) analyzer. T.Chuii microalgae samples were cultured within 8 days at BBPBAP Jepara, Central Java, Indonesia. The microalgae sediment was dried at 80°C for 24 hours then was powdered by means of a mortar. Thereafter, the dried powder of microalgae was filtered with a size of 60 mesh. Titanium dioxide (TiO2) nanoparticles were used as catalysts with the particle size of < 25 nm; these were obtained from Singapore’s Sigma Aldrich. Amount of 0.03 mg of TiO2 and 10 mg of T.Chuii microalgae were mixed mechanically using a mortar to guarantee the homogeneous blend, and then this sample was heated up in the oven for 14 hours at 80°C. The TG experiment was performed at a temperature range 25 to 900°C with atmospheric air at a flow rate of 50 mL/min and a heating rate of 15 °C/min. Differential method of Arrhenius is applied to evaluate kinetic parameters, including reaction order (n), activation energy (Ea), and pre-exponential factor (log A) that were 0.9; 74,191 kJ/mol and 6.38 min-1 for the stage II and 0.87; 118.47 kJ/mol and 7.29 min-1 for stage V.

Arrhenius Kinetic Analysis during Combustion of Spirulina platensis Microalgae

Characteristics and potential of microalgae Spirulina platensis as an energy source were studied in regard to the decomposition patterns, as well as kinetic and thermodynamic parameters. The thermogravimetric analysis was performed using the TGA instrument (Mettler Toledo TG DSC 1) at a heating rate of 30 °C/min, with an atmospheric air flow-rate of 100 ml/min at the temperature range of 25-1000 °C. The kinetic was evaluated using a differential method of Arrhenius. The results showed that Spirulina platensis microalgae decomposed into three stages. The first stage is related to the evaporation of moisture, the second stage is associated with the release of volatile matter, and the final stage is the combustion stage of char. The kinetic evaluation resulted in the respective activation energy (), pre-exponential factor (log A) and reaction order (n) are 53.57 kJ/mol, 4.4 min-1, and 1.73. It also understands from the thermodynamic analysis that the respective values of enthalpy (), Gibbs free energy ( and the entropies ( were 48.50 kJ/mol, 146,73 kJ/mol, and-174,78 J/mol.

Pyrolytic Characteristics and Kinetic Parameters Evaluation of Cassava Stalks Using Thermogravimetric Analyzer

Pyrolytic characteristics and kinetics of cassava stalks as a renewable energy source were delved via a thermogravimetric (TG) analyzer. About 10 mg powder of the sample was heated up in the TG cavity under inert conditions with 50 ml.min-1 nitrogen flow rate and operated at 20 °C min-1 of heating program. The pyrolysis process of cassava stalks was taken place into three main stages, in which the peak reaction occurred at the second stage with 70% of the mass was degraded. The differential method of Arrhenius kinetic evaluation resulted in the values of reaction order (n) that was 0.99, activation energy that was 89.46 kJ/mol and logarithmic frequency factor (log A) was 7.7 min-1.

Effects of steam-exploded wood as an insoluble dietary fiber source on the performance characteristics of broilers

Effects of modified insoluble fiber originating from steam-exploded Quercus mongolica were studied relative to growth performance, blood parameters, intestinal morphology, and other intestinal characteristics in poultry broilers. First, the effect of steam-explosion on physicochemical properties of insoluble fiber from Q. mongolica was investigated. Steam-explosion (severity factor Log (Ro) = 3.94) was found to increase the physical properties (water-holding capacity, oil-holding capacity, and swelling capacity) of Q. mongolica chip to different extents. Effects of feeding different concentrations of steam-exploded Q. mongolica on performance characteristics of broilers were investigated. Experimental diets of broilers consisted of a control diet (free of steam-exploded Q. mongolica), and four diets containing 0.5% to 2.0% steam-exploded Q. mongolica (severity factor Log (Ro) = 3.94). A diet containing 1.0% steam-exploded Q. mongolica promoted broiler growth performance (body weight (858.9 g) and improved blood characteristics (130.0 mg/dL), intestinal morphology (V:C ratio 7.50), and organ weights (length of intestine 17.6 cm/100 g body weight).

Distribution and accumulation of perfluororinated chemicals (PFCs) in water and sediment in two urban large lakes, Hanoi

The perfluororinated chemicals (PFCs) were determined in 40 surface water samples anf 36 sediment samples which were collected in two large urban lakes of Hanoi that are West lake and Yen So lake in rainy and dry seasons. Concentrations of total analysed PFCs was averaged of 10.78ng/L (8.13 – 13.25 ng/L) in water of West lake and 14.55 ng/L (12.42 – 17.64 ng/L) in water of Yen So lake, respectively. The average amount of PFCs in sediment of West lake was 0.11 ng/g dry sample (0.03-0.26 ng/g dry sediment) and PFCs of Yen So lake was 0.79 ng/g dry sample (0.08-2.01 ng/g dry sediment). The dominant PFCs with short cabon chain of PFC moleculars that were found a range of C4 to C10 for water and a range of C8 to C10 for sediment in two lakes. PFCs accumulation was recognized in sediment and water of both lakes Yen So and West lake with distribution factor (log KD) in a range of 1.05 and 2.91.

Oil Reservoir Permeability Estimation from Well Logging Data Using Statistical Methods (A Case Study: South Pars Oil Reservoir)

Permeability is a key parameter that affects fluids flow in reservoir and its accurate determination is a significant task. Permeability usually is measured using practical approaches such as either core analysis or well test which both are time and cost consuming. For these reasons applying well logging data in order to obtaining petrophysical properties of oil reservoir such as permeability and porosity is common. Most of petrophysical parameters generally have relationship with one of well logged data. But reservoir permeability does not show clear and meaningful correlation with any of logged data. Sonic log, density log, neutron log, resistivity log, photo electric factor log and gamma log, are the logs which effect on permeability. It is clear that all of above logs do not effect on permeability with same degree. Hence determination of which log or logs have more effect on permeability is essential task. In order to obtaining mathematical relationship between permeability and affected log data, fitting statistical nonlinear models on measured geophysical data logs as input data and measured vertical and horizontal permeability data as output, was studied. Results indicate that sonic log, density log, neutron log and resistivity log have most effect on permeability, so nonlinear relationships between these logs and permeability was done.

Predicting Survival of Salmonella in Low–Water Activity Foods: An Analysis of Literature Data

Factors such as temperature, water activity (aw), substrate, culture media, serotype, and strain influence the survival of Salmonella in low-aw foods. Predictive models for Salmonella survival in low-aw foods at temperatures ranging from 21 to 80°C and water activities below 0.6 were previously developed. Literature data on survival of Salmonella in low-aw foods were analyzed in the present study to validate these predictive models and to determine global influencing factors. The results showed the Weibull model provided suitable fits to the data in 75% of the curves as compared with the log-linear model. The secondary models predicting the time required for log-decimal reduction (log δ) and shape factor (log β) values were useful in predicting the survival of Salmonella in low-aw foods. Statistical analysis indicated overall fail-safe secondary models, with 88% of the residuals in the acceptable and safe zones (&lt;0.5 log CFU) and a 59% correlation coefficient (R2 = 0.35). A high variability in log δ-values and log β-values was observed, emphasizing the importance of experimental design. Factors of significant influence on the times required for first log-decimal reduction included temperature, aw, product, and serotype. Log β-values were significantly influenced by serotype, the type of inoculum (wet or dry), and whether the recovery media was selective or not. The results of this analysis provide a general overview of survival kinetics of Salmonella in low-aw foods and its influencing factors.

Separation of Tegafur and its Impurities by Reversed-Phase High-Perfomance Liquid Chromatography

The chromatographic behavior of tegafur and its impurities on a naphthalene Cosmosil piNAP column under reversed-phase high-performance liquid chromatography conditions was examined. A good description of the retention was achieved through the application of statistical weights to the widely used quadratic relationships between the logarithm of the retention factor (log k) and the organic solvent concentration in the mobile phase. Optimum conditions for isocratic separation of the compounds were found with acetonitrile concentration of 10-30% in the mobile phase

Determination of lipophilicity for antitumor acridinone derivatives supported by gradient high-performance liquid chromatography method

The lipophilicity values of selected acridinone (imidazoacridinone and triazoloacridinone) derivatives were measured by gradient reversed-phase high-performance liquid chromatography (RP-HPLC) using a C18 stationary phase with a water/acetonitrile mixture as a mobile phase. The retention times obtained served as input data and appropriate log kw values (i.e., the retention factor log kw extrapolated to 0% organic modifier) as an alternative to log P were calculated using the DryLab program. The relationships between the lipophilicity (log kw) and the chemical structure of the studied compounds, as well as correlation between experimentally determined lipophilicities (log kw) and log P data calculated using some commonly available software, are discussed.