α-Amylolysis of native potato and corn starches - SEM, AFM, nitrogen and iodine sorption investigations

Scanning electron microscopy (SEM), atomic force microscopy (AFM), as well as iodine and nitrogen sorption measurements were applied to investigate potato and corn starch granules surface after an action of Bacillus subtilis α-amylase. The SEM images revealed holes and pits (corn starch) or scratches (potato starch) on the surface of modified granules. These results were confirmed by AFM investigation which showed the presence of depressions of approximately 121 nm in diameter. Structure of the surface was not uniform. It consisted of small particles, amylopectin blocklets, of approximately 20 nm in diameter. They became more distinctive after α-amylolysis. Values of iodine binding capacity (IBC) obtained for hydrolyzed granules were lower than for native ones which indicated that the amylose and amylopectin chains building their surface were shortened. Specific surface area, volume and average diameter of mesopores increased for both starches after α-amylolysis.     

Carbon coating with combined super-hydrophobic and self-lubricating properties on titanium silicon carbide

Carbon coating on Ti₃SiC₂ with combined super-hydrophobic and self-lubricating properties was synthesized by chlorination at 1000 °C followed by modification of the CF₃(CF₂)₅CH₂CH₂SiCl₃ film. Raman spectroscopy confirmed the conversion from Ti₃SiC₂ to highly graphitized carbon coating. Scanning electron microscopy observation showed a highly porous microstructure of graphite flakes on the coating surface. The porous structure as well as organic film on carbon coating endowed the surface with super-hydrophobic property. Because of chemical inertia of the carbon coating and the modifier, the super-hydrophobic surface was very stable under various environments. Carbon coating was a good solid lubricant and greatly reduced friction coefficient of Ti₃SiC₂ sliding against Si₃N₄, which was important for Ti₃SiC₂ used as engineering material.     

Fly ash as a sorbent for boron removal from aqueous solutions: Equilibrium and thermodynamic studies

ABSTRACT

This study presents the application of fly ash from brown coal and biomass burning power plant as a sorbent for the removal of boron ions from an aqueous solution. The adsorption process efficiency depended on the parameters, such as adsorbent dosage, pH, temperature, agitation time and initial boron concentration. The experimental data fitted well with the Freundlich isotherm model and the maximum capacity was found to be 16.14 mg g^?1. The adsorption kinetics followed the pseudo-second-order model. Also, the intra-particle diffusion model parameters were calculated. Thermodynamic parameters such as change in free energy (ΔG°), enthalpy (ΔH°), entropy (ΔS°) revealed on exothermic nature of boron adsorption onto the fly ash.     

High resolution SEM characterization of nano‐precipitates in ODS steels

The performance of the present‐day scanning electron microscopy (SEM) extends far beyond delivering electronic images of the surface topography. Oxide dispersion strengthened (ODS) steel is on of the most promising materials for the future nuclear fusion reactor because of its good radiation resistance, and higher operation temperature up to 750°C. The microstructure of ODS should not exceed tens of nm, therefore there is a strong need in a fast and reliable technique for their characterization. In this work, the results of low‐kV SEM characterization of nanoprecipitates formed in the ODS matrix are presented. Application of highly sensitive photo‐diode BSE detector in SEM imaging allowed for the registration of single nm‐sized precipitates in the vicinity of the ODS alloys. The composition of the precipitates has been confirmed by TEM‐EDS.     

Enzymes in organic synthesis. 2. Synthesis of enantiomerically pure prostaglandin intermediates by Enzymatic Hydrolysis of (1SR, 5RS, 6RS, 7RS)-7-acetoxy-6-acetoxymethyl-2-oxabicyclo[3.3.0]octan-3-one

Subtilisin DY as well as alkaline protease from Bacillus licheniformis 41 p catalyze the hydrolysis of (1SR, 5RS, 6RS, 7RS)-7-acetoxy-6-acetoxymethyl-2-oxabicyclo[3.3.0]octan-3-one ( rac-1 ) with practically useful enantio- and regioselectivity. Under the hitherto found optimal conditions (1S, 5R, 6R, 7R)-7-hydroxy-6-hydroxymethyl-2-oxabicyclo[3.3.0]octan-3-one ( 4 ), an important intermediate in prostaglandin syntheses, could be prepared in a yield of 16% with an enantiomeric excess of 99%. The enantiomer ( ent-4 ) was obtained with the same enantiomeric excess in 20% yield. The chemical yields are related to the racemic starting material rac-1 .     

Effect of ALDH1A1 Gene Knockout on Drug Resistance in Paclitaxel and Topotecan Resistant Human Ovarian Cancer Cell Lines in 2D and 3D Model

Ovarian cancer is the most common cause of gynecological cancer death. Cancer Stem Cells (CSCs) characterized by drug transporters and extracellular matrix (ECM) molecules expression are responsible for drug resistance development. The goal of our study was to examine the role of aldehyde dehydrogenase 1A1 (ALDH1A1) expression in paclitaxel (PAC) and topotecan (TOP) resistant ovarian cancer cell lines. In both cell lines, we knocked out the ALDH1A1 gene using the CRISPR/Cas9 technique. Additionally, we derived an ALDH1A1 positive TOP-resistant cell line with ALDH1A1 expression in all cells via clonal selection. The effect of ALDH1A1 gene knockout or clonal selection on the expression of ALDH1A1, drug transporters (P-gp and BCRP), and ECM (COL3A1) was determined by Q-PCR, Western blot and immunofluorescence. Using MTT assay, we compared drug resistance in two-dimensional (2D) and three-dimensional (3D) cell culture conditions. We did not observe any effect of ALDH1A1 gene knockout on MDR1/P-gp expression and drug resistance in the PAC-resistant cell line. The knockout of ALDH1A1 in the TOP-resistant cell line resulted in a moderate decrease of BCRP and COL3A1 expression and weakened TOP resistance. The clonal selection of ALDH1A1 cells resulted in very strong downregulation of BCPR and COL3A1 expression and overexpression of MDR1/P-gp. This finally resulted in decreased resistance to TOP but increased resistance to PAC. All spheroids were more resistant than cells growing as monolayers, but the resistance mechanism differs. The spheroids’ resistance may result from the presence of cell zones with different proliferation paces, the density of the spheroid, ECM expression, and drug capacity to diffuse into the spheroid.     

The Use of a Novel Ferulic Acid Esterase from Lactobacillus acidophilus K1 for the Release of Phenolic Acids from Brewer's Spent Grain

In this work, an extracellular ferulic acid esterase was produced in bioreactor cultivations of Lactobacillus acidophilus K1 strain. The enzyme was partially purified using ultrafiltration (10 kDa), dialysis (4–6 kDa) and Fast Protein Liquid Chromatography (Sepharose CM, Sephacryl S‐300). A considerable increment of enzyme activity (31‐fold) in the final preparation was achieved. Two distinct bands (approx. 21.5 kDa and 39 kDa) were obtained after SDS‐PAGE. A high similarity of the purified enzyme (LC‐MS/MS analysis) to tannase and ferulic acid esterase from Burkholderia ambifaria MEX‐5 was obtained. The optimal pH and temperature for the enzyme activity were 6.3 and 37°C, respectively. The enzyme preparation effectively released phenolic acids (mainly ferulic and p‐coumaric acid) from brewer's spent grain. This novel enzyme preparation can be used for the utilisation of a valuable and inexpensive by‐product of the brewing industry.     

Influence of nonlinear coupling of pulses on spatio-temporal compression

Abstract

Properties of a novel configuration of an optical (spatio-temporal) pulse compressor, that is based on a Kerr-type planar waveguide into which two pulses are simultaneously launched, are studied. It is assumed that the pulse which is the subject of the compression propagates in the anomalous dispersion regime, while the auxiliary pulse is in normal dispersion. The best parameters of the proposed compressor are obtained when duration of the auxiliary pulse is so large that this dispersion can be neglected, while energy of the second pulse is above the threshold of first-order soliton generation. It is observed that in such a configuration the compression occurs simultaneously with the generation of a soliton-like solution. It is argued that the proposed configuration with two simultaneously propagating pulses has advantages over the configuration with a single pulse, namely the maximal compression factor and the optimal length of the compressor is, respectively, more than 3 times larger and, at least, 10 times greater than the corresponding values of the compressor with a single pulse. It is also demonstrated that such a compressor can be considered as a universal device, since its operation depends only slightly on the initial parameters of the pulse subject to the compression.     

Conventional and Non-conventional Edible Oils: An Indian Perspective

The Indian dietary pattern has undergone major changes over the past 40 years. Many of these changes involve modification in dietary intake of fats and oils. In developing countries like India, vegetable oils are replacing animal fats because of the cost and health concerns. A wide range of vegetable oils are available in the market but the choice of healthy cooking oil has been a controversial subject since ideas keep on changing as new evidence accumulates. One of the factors holding back the increased use of value-added healthy oils in India is that most potential consumers are genuinely not aware of their health benefits. Edible oil consumption is primarily a community-driven phenomenon in India. The purpose of this paper is to highlight the current scenario of edible oils in India, their composition, health benefits, food applications, stability issues and future aspects as buying the right oil for health has become of great importance.