Antiproliferative and Proapoptotic Activities of Methanolic Extracts from Ligustrum vulgare L. as an Individual Treatment and in Combination with Palladium Complex

The aim of this study is to examine the growth inhibitory effects of methanolic leaf and fruit extracts of L. vulgare on HCT-116 cells over different time periods and their synergistic effect with a Pd(apox) complex. The antiproliferative activity of plant extracts alone or in combination with the Pd(apox) complex was determined using MTT cell viability assay, where the IC(50) value was used as a parameter of cytotoxicity. Results show that antiproliferative effects of L. vulgare extracts increase with extension of exposure time, with decreasing IC(50) values, except for 72 h where the IC(50) values for methanolic leaf extract were lower than for the fruit extract. The Pd(apox) complex alone had a weak antiproliferative effect, but combination with L. vulgare extracts caused stronger effects with lower IC(50) values than with L. vulgare extracts alone. The type of cell death was explored by fluorescence microscopy using the acridin orange/ethidium bromide method. Treatments with plant extracts caused typical apoptotic morphological changes in HCT-116 cells and co-treatments with Pd(apox) complex caused higher levels of apoptotic cells than treatment with plant extracts alone. The results indicate that L. vulgare is a considerable source of natural bioactive substances with antiproliferative activity on HCT-116 cells and which have a substantial synergistic effect with the Pd(apox) complex.     

The A9 Core Sequence from NRPS Adenylation Domain Is Relevant for Thioester Formation

The adenylation (A) domain in nonribosomal peptide synthetases catalyses a two-step reaction in which an amino acid is activated and then transferred to the neighbouring thiolation (T) domain. In this study, we investigated the role of the conserved A9 core sequence of the A-domain of tyrocidine synthetase 1, by analysis of single amino acid mutations in the A9 region. Mutation of an absolutely conserved proline (P490G) significantly reduced the conformational stability of the protein, as evidenced by increased susceptibility to proteolytic cleavage and denaturation. All mutant A-domains were capable of amino acid activation, but the activity in the overall reaction was reduced. Surprisingly, the S491R mutant (mutation at the first residue following the A9 motif) showed elevated overall activity compared to the wild-type protein. Our results suggest that the A9 core sequence plays a role in the second reaction step, in which it could serve as a "clip" for the proper positioning of residues important for the interaction with the T-domain, and/or stabilisation of the thioester-forming conformation.     

MODELLING GAS-SOLID FLOW IN A PNEUMATIC-FLASH DRYER

ABSTRACT

Investigations of aerodynamics of gas-solid flow in a pneumatic-flash dryer in semiindustrial scale have been carried out. Apparatus was composed of three elements with varying cross-sectional area connected together, i.e. expanding cone, decreasing cone and a vertical pipe with constant diameter. A mathematical model of the dryer is based on the continuity equations for both gas and solid phase and on differential equations for momentum balance of the gas-solid mixture and momentum balance of the solid phase. The model has been solved by means of Gear's numerical method. The effect of various empirical correlations for the solid-wall friction factor has been shown. Distributions, resulting from the model, for pressure, gas velocity, panicle velocity, voidage and residence time of panicle along the axis of apparatus have been presented. The results of numerical calculations have been verified on the basis of measurements in pan.     

Analysis of the strain and hardness in self-cured and light-cured self-adhesive resin based cement

The study showed an application of the 3?D Digital Image Correlation Method (3?D-DIC) for detection of von Mises strain in samples of the self-etch, self-adhesive resin based cement (RBC). The aim was to determine and compare strain in the self-cured and light-cured Maxcem Elite, furthermore to investigate the hardness of these two cement-types. The experiment was carried out using two groups of Maxcem Elite (Kerr, Orange, CA, USA) samples; each tested group includes five (ø5?×?2?mm sized) samples, for both self-curing and light-curing mode. All samples were prepared by filling teflon ring-type molds. In addition, Vickers micro-hardness was measured for all samples. Maxcem Elite showed similar maximum strain values from 10% to 12% for both groups. Besides the maximum strain value, the 3?D-DIC method also enabled monitoring the change of strain field even after the recommended polymerization time. This method has shown that the polymerization shrinkage continues even after 10?min which disagreed with manufacturer’s suggestion. Group II showed maximum strain values of 12% in the peripheral zone after 10?min, in the last Stage (Stage 60). Statistically significant difference was not found in the overall strain between self- and light-cured Maxcem Elite neither peripherally (p?=?0.118) nor centrally (p?=?0.879). However, statistical significance was found in strain regarding central and peripheral zone in both, self-cured (p?=?0.020) and light-cured (p?=?0.002) Maxcem Elite. The mean von Mises strain values in the periphery of the samples (Section 0) were significantly higher compared to strain values in the center of the samples (for Section 1 and 2). The last stage (Stage 60) of the light-cured Maxcem Elite polymerization showed significantly higher values of von Mises strain compared to initial stage (Stage 0). Higher values of micro-hardness were noticed on the surfaces directly exposed to LED lamp after performing measurements of micro-hardness on light-cured samples.     

Internal configurations for a multi-product dividing wall column

This paper addresses possibilities and peculiarities associated with establishing the most beneficial internal configuration of a complex dividing wall column (DWC), using as a base case the separation of a multicomponent aromatics mixture into four or five product streams. As expected, the V_min-diagram method proved to be an appropriate tool in such a study, as a means for identifying and assessing promising configurations and at the same time to provide the necessary inputs and reliable initial guesses for detailed simulation-based determination of energy and stage requirements. A new, energy efficient two-top product configuration is introduced that appears to be an interesting option for a four-product DWC.     

The influence of Ce-based coatings as pretreatments on corrosion stability of top powder polyester coating on AA6060

Cerium-based conversion coatings (CeCCs) are one of the most prospective alternatives to the widely used chromate conversion coatings (CCCs) due to their anticorrosion efficiency, environmentally friendly nature and low cost. In this work, the CeCCs on AA6060 were prepared by immersion into aqueous cerium salt solutions at room temperature, and subsequently post-treated in heated phosphate solution. The effect of counter ion (nitrate and chloride) on the coating properties was studied testing CeCCs as sole or conversion layers for the top polyester coating. Since the 60 μm thick polyester coating was applied, an artificial defect of 0.8 mm hole was introduced to faster assess the differences between pretreatments. The system with CCC pretreatment was used as reference. Corrosion properties were investigated in 0.5 M NaCl solution by electrochemical impedance spectroscopy while the adhesion strength was measured by NMPR (N-methyl-2-pyrrolidone) and pull-off tests. As shown, the post-treated chloride-based CeCC offered better protection than crack-free thin nitrate-based CeCC, when used as sole coatings. On the other hand, it was brought to evidence that in combination with top powder polyester coating, the CeCC deposited from nitrate solution exhibited better protection compared to protective system pretreated with chloride-based one. Excellent polyester coating adhesion was found independently on aluminium surface pretreatment.     

Behaviour of bone origin hydroxyapatite at elevated temperatures and in O2 and CO2 atmospheres

In the present work the behaviour of HAp extracted from pig bones at elevated temperatures up to 1000 °C in O₂ and CO₂ atmospheres has been studied. It has been found that CO₂ atmosphere arrests HAp decomposition. Chemical analysis and infrared spectroscopy reveal that no free CaO appears and no decrease of CO₃⁻² group concentration occurs in the material calcined in CO₂ atmosphere. In the O₂ atmosphere at elevated temperatures, CaO and CO₂ are emitted from the samples, although the remaining material retains the HAp structure as indicated by the X-ray diffraction.     

Method for determining refractory specimen heat resistance

The most important properties governing the operation of refractories are refractoriness, service temperature and heat resistance. The heat resistance of specimens based on Al₂O₃ is determined by a standard laboratory procedure with cooling in water (JUS.B.D.8.319). In order to analyze possible worsening of specimen property indices before, during and after rapid water cooling a Pro Plus Program control system is used. This program has also been used for analyzing the nature of grain size distribution. Simultaneously mechanical properties such as strength, dynamic elasticity modulus, determined from data for measuring resonance frequency and ultrasonic (US) velocity, are determined. The correlation between worsening property indices, US velocity, strength and heat resistance is studied in this work. The results obtained are used for a model predicting refractory specimen heat resistance. Translated from Novye Ogneupory, No. 4, pp. 55–58, April 2008. An erratum to this article can be found at