Ozone Production in a Dielectric Barrier Discharge with Ultrasonic Irradiation

Ozone production has been investigated using an atmospheric pressure dielectric barrier discharge in pure O₂ at room temperature with and without ultrasonic irradiation. It was driven at a frequency of either 15 kHz or ～40 kHz. The ozone production was highly dependent on the O₂ flow rate and the discharge power. Furthermore, powerful ultrasonic irradiation at a fundamental frequency of ～30 kHz with the sound pressure level of ～150 dB into the discharge can improve the ozone production efficiency, particularly when operated at the frequency of 15 kHz at the flow rate of 15 L/min.     

Novel conventional and chelating anion exchange resins with amino ligands for sorption of silver

ABSTRACT

The polymeric resins containing diethylenetriamine, tetraethylenepentamine, 2-(diethylamino)ethanol, 1-methylimidazole, and 1,2-dimethylimidazole ligands have been synthesized from vinylbenzyl chloride-divinylbenzene copolymers and used in the removal of Ag(I) from chloride solution. The best Ag(I) sorption was reached in the case of 1-methylimidazole resin. Resins retain their capacity towards Ag(I) in five consecutive sorption/desorption cycles. The resins with imidazole ligands were highly selective for Ag(I) from synthetic chloride solution and they did not sorb chloride complexes of Cu(II). Additionally, the recovery of Ag(I) was tested from real chloride solution coming from leaching of the copper concentrate from Lubin Concentrator (KGHM Polska Mied? S.A.).     

Al-Tolerant Barley Mutant hvatr.g Shows the ATR-Regulated DNA Damage Response to Maleic Acid Hydrazide

ATR, a DNA damage signaling kinase, is required for cell cycle checkpoint regulation and detecting DNA damage caused by genotoxic factors including Al³⁺ ions. We analyzed the function of the HvATR gene in response to chemical clastogen-maleic acid hydrazide (MH). For this purpose, the Al-tolerant barley TILLING mutant hvatr.g was used. We described the effects of MH on the nuclear genome of hvatr.g mutant and its WT parent cv. “Sebastian”, showing that the genotoxic effect measured by TUNEL test and frequency of cells with micronuclei was much stronger in hvatr.g than in WT. MH caused a significant decrease in the mitotic activity of root cells in both genotypes, however this effect was significantly stronger in “Sebastian”. The impact of MH on the roots cell cycle, analyzed using flow cytometry, showed no differences between the mutant and WT.     

Specific cationic photoinitiators for near UV and visible LEDs: Iodonium versus ferrocenium structures

Two iodonium salts based on a coumarin chromophore are investigated for polymerization upon light emitting diode irradiations (LEDs). They work as one‐component photoinitiators. They initiate the cationic polymerization of epoxides (under air) and vinylethers (laminate) upon exposure to violet LEDs (385 and 405 nm). Excellent polymerization profiles are recorded. Their efficiency is quite similar to that of a ferrocenium salt. Interpenetrating polymer networks can also be obtained through a concomitant cationic/radical photopolymerization of an epoxy/acrylate blend monomer. The light absorption properties of these new salts as well as the involved photochemical mechanisms are investigated for the first time through electron spin resonance, laser flash photolysis, steady state photolysis experiments. Molecular orbital calculations are also used to shed some light on the initiation mechanisms. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42759.     

Study on the new bone cement based on calcium sulfate and Mg,CO3 doped hydroxyapatite

In order to improve some features of bone substitutes the new self-setting composite-type implant material based on Mg²⁺/CO₃^2? co-substituted hydroxyapatite (Mg-CHA) and calcium sulfate hemihydrate (CSH) was developed. Synthetic hydroxyapatites doped with small amounts of additives found in natural bone (e.g. Mg²⁺ and CO₃^2?) are regarded as promising components of calcium phosphate bone cements (CPCs). The CPCs, now available on the market, due to low resorption rate are too stable to permit material degradation and are slowly replaced by the newly formed bone. To improve cement resorption we used calcium sulfate which is a well-known biodegradable and biocompatible bone defect filler. Combining properties of Mg-CHA and CSH allowed developing a new, promising, easy shapeable implant material with high potential for bone regeneration.     

Effects of various roasting conditions on acrylamide,acrolein, and polycyclic aromatic hydrocarbons content in cocoa bean and the derived chocolates

The effect of roasting parameters such as the temperature (135 and 150°C) and relative humidity of air (RH of 0.3 and 5.0%) on acrylamide, acrolein, and polycyclic aromatic hydrocarbon (PAH) levels in whole and crushed cocoa beans and chocolates derived from these beans was studied. Acrylamide was identified in all tested samples of roasted cocoa beans, irrespective of process conditions. Its contents in chocolates produced from these beans were similar. The highest acrylamide concentration was found in whole cocoa beans roasted at 135°C and RH of 5.0%. Small amounts of acrolein were present only in the roasted whole cocoa beans while neither the roasted crushed cocoa beans nor chocolates contained this aldehyde. Roasting conditions significantly affected the profile and content of PAHs in whole and crushed cocoa beans and the richest in PAHs were crushed cocoa beans roasted at 150°C and RH of 5.0%. The chocolates obtained in this study contained significantly higher concentrations of PAHs than the roasted cocoa beans used for their production. The results of the study demonstrate that optimization of roasting conditions may reduce levels of all these harmful substances in cocoa beans.     

Characterization of new class III lantibiotics--erythreapeptin, avermipeptin and griseopeptin from Saccharopolyspora erythraea, Streptomyces avermitilis and Streptomyces griseus demonstrates stepwise N-terminal leader processing

Lantibiotics are a large group of ribosomally synthesized peptides post-translationally modified to incorporate the amino acid lanthionine. They are classified, according to their biosynthetic pathway and bioactivity, into three major subtypes. Of Actinomycetes type III lantibiotics, only four peptides (SapB, SapT, LabA1, and LabA2) have been described and structurally characterized, although homologous gene clusters are abundant in other Actinomycetes. All these gene clusters share a similar architecture with a characteristic Ser/Ser/Cys motif in precursor peptides, which has previously been suggested to act as a precursor for lanthionine (SapB) and labionin (LabA2) rings. Mass spectrometry screening led to the discovery and characterization of three new representatives of type III lantibiotics: Avermipeptin (Avi), Erythreapeptin (Ery), and Griseopeptin (Gri) from Streptomyces avermitilis DSM 46492, Saccharopolyspora erythraea NRRL 2338, and Streptomyces griseus DSM 40236, respectively. Apart from the assignment of these peptides to their corresponding gene clusters, additional investigations on Avi, Ery and Gri peptides indicate stepwise leader processing by putative aminopeptidase-like protease(s), thus yielding mixtures of differently N-terminal-processed lantibiotic peptides. Similar peptide processing was observed for a heterologously expressed eryth biosynthetic gene cluster expressed in a Streptomyces host system. Remarkably, all isolates of the new type III lantibiotics contain both the amino acids lanthionine and labionin, thus implying dual-mode cyclase activity of the processing lyase-kinase-cyclase enzymes. These findings have implications for the structures and maturation of other type III lantibiotics from Actinomycetes.