Application of three-electrode electrolytic cell to evaluate thin films of vegetable and mineral oils

Films (∼5 μm) of rapeseed and mineral oils with or without antioxidants were coated on steel disc electrodes. Initial stages of corrosion and oxidation were monitored by potentiodynamic polarization and impedance spectroscopy in ammonium borate electrolyte at pH 9.0. Fresh films lead to spatial separation of electrochemical reactions without major changes in corrosion mechanism. However, heating in air (4 h, 70 °C) reduced current densities by 2 orders and produced dramatic changes in impedance and phase angle patterns. Data fitting was proposed and reasons discussed why mild heating changed the course of corrosion so strongly.     

Click through Rate Effectiveness Prediction on Mobile Ads Using Extreme Gradient Boosting

Online advertisements have a significant influence over the success or failure of your business. Therefore, it is important to somehow measure the impact of your advertisement before uploading it online, and this is can be done by calculating the Click Through Rate (CTR). Unfortunately, this method is not eco-friendly, since you have to gather the clicks from users then compute the CTR. This is where CTR prediction come in handy. Advertisement CTR prediction relies on the users’ log regarding click information data. Accurate prediction of CTR is a challenging and critical process for e-advertising platforms these days. CTR prediction uses machine learning techniques to determine how much the online advertisement has been clicked by a potential client: The more clicks, the more successful the ad is. In this study we develop a machine learning based click through rate prediction model. The proposed study defines a model that generates accurate results with low computational power consumption. We used four classification techniques, namely K Nearest Neighbor (KNN), Logistic Regression, Random Forest, and Extreme Gradient Boosting (XGBoost). The study was performed on the Click-Through Rate Prediction Competition Dataset. It is a click-through data that is ordered chronologically and was collected over 10 days. Experimental results reveal that XGBoost produced ROC-AUC of 0.76 with reduced number of features.     

Comparison of carbon dioxide and nuclear waste storage costs in Lithuania

Nuclear power and carbon capture and storage (CCS) are key greenhouse gas mitigation options under consideration across the world. Both technologies imply long-term waste management challenge. Geological storage of carbon dioxide (CO₂) and nuclear waste has much in common, and valuable lessons can be learnt from a comparison. Seeking to compare these technologies economic, social and environmental criteria need to be selected and expressed in terms of indicators. Very important issue is costs and economics of geological storage of carbon dioxide and nuclear waste. The costs of storage are one of the main indicators for assessment of technologies in terms of economic criteria.The paper defines the costs of the geological storage of CO₂ and nuclear waste in Lithuania, drawing also on insights from other parts of the world. The costs of carbon dioxide and nuclear waste storage are evaluated in UScnt/kWh and compared. The paper critically compares the characteristics and location of the both sources of and storage options for CO₂ and nuclear waste in Lithuania. It discusses the main costs categories for carbon dioxide and nuclear waste storage. The full range of potential geological storage options is considered and the most reliable options for carbon dioxide and nuclear waste are selected for the comparative costs assessment.     

Solubility engineering of the HhaI methyltransferase

DNA methylation is involved in epigenetic control of numerouscellular processes in eukaryotes, however, many mechanisticaspects of this phenomenon are not yet understood. A bacterialprototype cytosine-C5 methyltransferase, M.HhaI, serves as aparadigm system for structural and mechanistic studies of biologicalDNA methylation, but further analysis of the 37 kDa proteinis hampered by its insufficient solubility (0.15 mM). To overcomethis problem, three hydrophobic patches on the surface of M.HhaIthat are not involved in substrate interactions were subjectedto site-specific mutagenesis. Residues M51 or V213 were substitutedby polar amino acids of a similar size, and/or the C-terminaltetrapeptide FKPY was replaced by a single glycine residue (     

Sustaining the Commitment to Multiculturalism: A Longitudinal Study in a Graduate Psychology Program.

Those committed to the multicultural transformation of the psychology profession must become familiar with ways to initiate and maintain this challenging process. The efforts of a graduate training program to sustain its multicultural evolution are presented along with longitudinal outcome data. Over time, diversity interventions were seen as more effective while differences in the success ratings among students of color and their White peers decreased. Reports of having heard about, seen, or experienced prejudicial behavior, however, remained unchanged. The institutionalization of multicultural change procedures, the revision of assessment instruments for long-term use, and the potential benefits of comparative diversity research are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Antimicrobial activity of chitosan‐based films against Salmonella typhimurium and Staphylococcus aureus

The antibacterial effect of polyamide 6/66‐chitosan blend and chitosan‐coated plastic films was compared to chitosan films and chitosan solution, against Salmonella typhimurium and Staphylococcus aureus. The chitosan films did not show inhibition halos; however, contact inhibition was observed. During the tests, the films absorbed moisture, increasing of the diameter discs in relation to the concentration of the chitosan for both microorganisms at least 31%. Chitosan plastic film coating (bilayer system) showed only contact inhibition, without increase in contact area. The films from polyamide 6/66‐chitosan blend had no antibacterial activity. The highest inhibitory effect resulted from a chitosan solution at 1000 and 2000 ppm for S. typhimurium and S. aureus, respectively. The results of this study showed that the antimicrobial activity was lessened when the chitosan was combined with the plastic matrix because of the absence of contact inhibition, and the best activity was obtained with films prepared by casting of chitosan solution.     

Effect of TiO2, LiF and Cr2O3 in the Crystallization of Cristobalite and Tridymite in Sintered Glass-Ceramics

Based on the poudretteite (K Na₂ B₃ Si₁₂ O₃₀) glass composition, six transparent glass frits were prepared. TiO₂, LiF and Cr₂O₃ were experimented on the base glass composition as nucleation catalysts. Only cristobalite and tridymite were developed through the sintering process of the glasses between 900 and 1100?°C. LiF enhances mainly tridymite with traces of cristobalite and in the opposite side the parent and both TiO₂ and Cr₂O₃ containing glasses catalyzed mainly cristobalite with traces of tridymite. The microstructure of the glass samples heat-treated at 1000?°C showed backbone-like, small rods, quadrant-, hexagonal crystals referred to the cristobalite and tridymite. The EDS microanalysis shows the presence of both alkalis, i.e. Na^?+? and K^?+?, in the cristobalite crystal structure while the residual glass contains K^?+?. The infrared spectroscopy indicates the band patterns of cristobalite and tridymite.     

Optimization of nano spray drying parameters for production of α-amylase nanopowder for biotheraputic applications using factorial design

Abstract

This study was designed to optimize the effect of operating conditions and formulation parameters using various additives to develop α-amylase nanoparticles. α-Amylase was chosen due to its importance in the substantial number of industrial processing with emphasis on pharmaceutical industry. Factorial statistical design was adopted to effectively optimize the size, yield value, residual enzyme activity, and morphology of α-amylase nanoparticles using Nano Spray Dryer BÜCHI B-90. The physicochemical characterization of the prepared nanopowder was carried out using zetasizer and scanning electron microscopy (SEM) and enzyme activity assay. Results showed that the type of additive and mesh size significantly influenced the particles size and yield value. SEM images showed three different structure patterns where particle morphology was influenced by Tween^® 80 or sucrose at low concentration (0.05%). Optimized spherical nanoparticles (600?nm) was obtained using 7 µm mesh cap size, sucrose (0.15%), 95% yield value, drying flow rate (100?L/min), and inlet temperature of 80?°C. Higher storage stability was detected for enzyme spray-dried using larger cap size. It was concluded that nano spray drying of aqueous enzyme solution under determined operating conditions produced stable α-amylase powders. This would extend the application of the enzyme in a variety of pharmaceutical products.     

Nocturnal Bees are Attracted by Widespread Floral Scents

Flower localization in darkness is a challenging task for nocturnal pollinators. Floral scents often play a crucial role in guiding them towards their hosts. Using common volatile compounds of floral scents, we trapped female nocturnal Megalopta-bees (Halictidae), thus uncovering olfactory cues involved in their search for floral resources. Applying a new sampling method hereby described, we offer novel perspectives on the investigation of nocturnal bees.     

Feed restriction and a diet's caloric value: The influence on the aerobic and anaerobic capacity of rats

Background

The influence of feed restriction and different diet's caloric value on the aerobic and anaerobic capacity is unclear in the literature. Thus, the objectives of this study were to determine the possible influences of two diets with different caloric values and the influence of feed restriction on the aerobic (anaerobic threshold: AT) and anaerobic (time to exhaustion: Tlim) variables measured by a lactate minimum test (LM) in rats.

Methods

We used 40 adult Wistar rats. The animals were divided into four groups: ad libitum commercial Purina^? diet (3028.0 Kcal/kg) (ALP), restricted commercial Purina^? diet (RAP), ad libitum semi-purified AIN-93 diet (3802.7 Kcal/kg) (ALD) and restricted semi-purified AIN-93 diet (RAD). The animals performed LM at the end of the experiment, 48 h before euthanasia. Comparisons between groups were performed by analysis of variance (p < 0,05).

Results

At the end of the experiment, the weights of the rats in the groups with the restricted diets were significantly lower than those in the groups with ad libitum diet intakes. In addition, the ALD group had higher amounts of adipose tissue. With respect to energetic substrates, the groups subjected to diet restriction had significantly higher levels of liver and muscle glycogen. There were no differences between the groups with respect to AT; however, the ALD group had lower lactatemia at the AT intensity and higher Tlim than the other groups.

Conclusions

We conclude that dietary restriction induces changes in energetic substrates and that ad libitum intake of a semi-purified AIN-93 diet results in an increase in adipose tissue, likely reducing the density of the animals in water and favouring their performance during the swimming exercises.