Drying of Tomato Pretreated with Calcium

Pieces of tomato pericarp were pretreated by soaking in CaCl₂ solution before convective drying. Drying was interrupted at prescribed water contents and volume of the piece, its area, perimeter and shape factor were measured. It was found that pretreatment cause shrinkage of tomato pieces by some 15%. Drying causes further shrinkage, which in both nontreated and pretreated tomato is larger than the volume of evaporated water. Microscopic examination showed that pretreatment of tomato with calcium ion causes larger tissue structure alterations in comparison to those observed in nontreated tomato. Calcium concentration gradients cause variable resistance of the tissue to deformation. During dehydration tissue is torn apart and large cavities are formed. It results in faster drying of pretreated tomato in comparison to drying of nontreated tomato.     

Determination of Pyrrolizidine Alkaloids in Honey with Sensitive Gas Chromatography-Mass Spectrometry Method

Pyrrolizidine alkaloids (PAs) are secondary metabolites produced by plants as a chemical defense against herbivores. Plants containing PAs are widely distributed in almost all geographical regions posing a risk of honey contamination. To provide safety of honey and decrease the potential risk for the consumers, a sensitive method based on gas chromatography-mass spectrometry enabling determination of a content of 1,2-unsaturated PAs in honey was developed. Honey samples were purified on MCX cartridges, and PAs were eluted with a solvent mixture consisting of ethyl acetate, methanol, ammonia, and triethylamine. Subsequently, 1,2-unsaturated alkaloids were reduced to their common backbone structures and derivatized with heptafluorobutyric anhydride. The method was validated according to SANTE 2015. All received parameters are in consistence with the document requirements as recovery ranged from 73.1 to 93.6%. The repeatability and reproducibility were calculated as relative standard deviation and ranged from 3.9 to 8.6% and from 10.6 to 17.8%, respectively. The limit of quantification was determined as 1 μg kg^?1. Good linearity of the method was obtained with the coefficient of determination R ²?>?0.99. The method was applied to 40 Polish and 14 Asian honey sample analyses.     

Isolation of genes coding for chitin-degrading enzymes in the novel chitinolytic bacterium, Chitiniphilus shinanonensis, and characterization of a gene coding for a family 19 chitinase

Chitiniphilus shinanonensis type strain SAY3(T) is a strongly chitinolytic bacterium, originally isolated from the moat water in Ueda, Japan. To elucidate the chitinolytic activity of this strain, 15 genes (chiA-chiO) coding for putative chitin-degrading enzymes were isolated from a genomic library. Sequence analysis revealed the genes comprised 12 family 18 chitinases, a family 19 chitinase, a family 20 β-N-acetylglucosaminidase, and a polypeptide with a chitin-binding domain but devoid of a catalytic domain. Two operons were detected among the sequences: chiCDEFG and chiLM. The gene coding for the polypeptide (chiN) showed sequence similarity to family 19 chitinases and was successfully expressed in Escherichia coli. ChiN demonstrated a multi-domain structure, composed of the N-terminal, two chitin-binding domains connected by a Pro- and Thr-rich linker, and a family 19 catalytic domain located at the C-terminus. The recombinant protein rChiN catalyzed an endo-type cleavage of N-acetyl-d-glucosamine oligomers, and also degraded insoluble chitin and soluble chitosan (degree of deacetylation of 80%). rChiN exhibited an inhibitory effect on hyphal growth of the fungus Trichoderma reesei. The chitin-binding domains of ChiN likely play an important role in the degradation of insoluble chitin, and are responsible for a growth inhibitory effect on fungi.     

Advantages of highly ionized pulse plasma magnetron sputtering (HIPIMS) of silver for improved E. coli inactivation

This study addresses the DC-magnetron sputtering (DCMS) of Ag-films on polyester and compares the results found for the E. coli inactivation with the inactivation obtained when applying highly ionized pulse plasma power magnetron sputtering (HIPIMS). The amounts of Ag needed to inactivate E. coli by HIPIMS sputtering were an order of magnitude lower than with DCMS indicating a significant saving of noble metal and concomitantly a faster E. coli inactivation was observed compared to samples sputtered with DCMS. Higher current densities applied with DCMS led to shorter E. coli inactivation times and this trend was observed also for HIPIMS sputtered samples. By DCMS the thicker layers needed to inactivate E. coli comprised slightly larger Ag-aggregates compared to the thinner Ag-layers sputtered by HIPIMS to inactivate E. coli within short times. Longer sputtering times by DCMS and HIPIMS lead to optically darker Ag-deposits reaching the absorption edge of silver absorption of ~ 1000 nm. Mass spectroscopic analyses indicated that HIPIMS produced a much higher amount of Ag¹⁺ and Ag²⁺ compared to DCMS due to the higher peak discharge current employed in the former case.     

Neuroplasticity and Multilevel System of Connections Determine the Integrative Role of Nucleus Accumbens in the Brain Reward System

A growing body of evidence suggests that nucleus accumbens (NAc) plays a significant role not only in the physiological processes associated with reward and satisfaction but also in many diseases of the central nervous system. Summary of the current state of knowledge on the morphological and functional basis of such a diverse function of this structure may be a good starting point for further basic and clinical research. The NAc is a part of the brain reward system (BRS) characterized by multilevel organization, extensive connections, and several neurotransmitter systems. The unique role of NAc in the BRS is a result of: (1) hierarchical connections with the other brain areas, (2) a well-developed morphological and functional plasticity regulating short- and long-term synaptic potentiation and signalling pathways, (3) cooperation among several neurotransmitter systems, and (4) a supportive role of neuroglia involved in both physiological and pathological processes. Understanding the complex function of NAc is possible by combining the results of morphological studies with molecular, genetic, and behavioral data. In this review, we present the current views on the NAc function in physiological conditions, emphasizing the role of its connections, neuroplasticity processes, and neurotransmitter systems.     

Preparation and characteristics of new chiral photochromic copolymers

The copolymers consisting of chiral (S)-(−)-1-(4-nitrophenyl)pyrrolidin-2-yl]methyl 2-methacrylate ((S)-PYM) and azobenzene methacrylic co-monomers: 2-(methyl{4-[(E)-(5-methylisoxazol-3-yl)diazenyl]phenyl}amino)ethyl 2-methacrylate (ISM) or 2-{[4-[4-{(2,6-dimethylpirymidin-4-yl)amino]sulfonyl}phenyl) diazenyl]phenyl}-(methyl)amino]ethyl 2-methacrylate (SUM) were synthesized by radical polymerization. The quantum chemical calculations were carried out to predict spectral and nonlinear optical properties of the materials in question. The copolymers showed reversible photochromic properties under illumination with light by change of UV–vis spectra and ellipsometric parameters. The ellipsometric measurements made it possible to determine the change of refractive index under illumination that was in the range between 0.017 and 0.041 depending on copolymer type. Photochromic gratings were inscribed on the surface of polymer films in two kinds of experiments, leading to interesting conclusion that the surface relief grating could be recorded by two interfering laser beams as well as by a single linearly polarized laser beam. The chirooptical properties of the materials were investigated by circular dichroism spectroscopy.     

A phenol-formaldehyde resin loaded with in situ synthesised silver nanoparticles

Attempts to obtain stable phenol-formaldehyde resins with silver nanoparticles embedded in their structure were performed in the study. Silver nanoparticles were formed in situ in the process of obtaining resole resins. The conditions of their formation allowed for effectively reducing silver ions and stabilising the creation of nanoparticles. Tannic acid was used as a reducing and stabilising substance and gelatin served as a supporting stabiliser. The possibility of using the obtained product as a wood binder was studied. It was confirmed that their adhesive properties are strong enough to bind blocks of pine wood. Thanks to the presence of silver nanoparticles, the product also exhibited antimicrobial activity which was confirmed against the Saccharomyces cerevisiae strain.