Linearization of multichannel amplifiers with the injection of second harmonics into the amplifier and predistortion circuit

A linearization technique that uses the injection of the fundamental signal second harmonics together with the fundamental signals at the amplifier input has been extended in this paper by introducing the injection the second harmonics into nonlinear microwave amplifier and so-called predistortion circuit. Predistortion circuit produces the third-order intermodulation signals that are injected at the amplifier input together with the second harmonics making the linearization procedure more independent on the phase variation of the second harmonics. In addition, a considerably better improvement is attained for the power of fundamental signals close to 1-dB compression point by applying the linearization technique proposed in this paper in comparison to the linearization with the injection of the second harmonics merely in the nonlinear amplifier

Perception of small farmers in Serbia regarding the use of ICT and possibilities of organic agriculture

During the last two decades there is a growing awareness of the importance of introducing organic agricultural production in Serbia due to issues of health, environmental protection and need for more sustainable agriculture. There is a need for education of small farmers on the possibilities of organic production and significance of information technologies for education, production and marketing. This paper aims to examine the perception on the possibilities of organic production and ICT use concerning their level of education. The study has included 143 farmers from Raška district, municipality Kraljevo. The statistical ANOVA analysis has been done by using the software package SPSS18 to explore an impact the education has on the perception of small farmers on the use of information technologies in education, production, and marketing of agricultural products. The results show statistically significant difference in the perception of small farmers on the usage of information technologies regarding their level of education.Publishe

Different coordination abilities of 1,7- and 4,7-phenanthroline in the reactions with copper(II) salts: Structural characterization and biological evaluation of the reaction products

The reactions between equimolar amounts of CuX2 (X = NO3− and CF3SO3−) and two aromatic nitrogen-containing heterocycles differing in the position of nitrogen atoms, 1,7- and 4,7-phenanthroline (1,7- and 4,7-phen), were performed in ethanol/methanol at room temperature. When CuX2 salts were mixed with 4,7-phen, two copper(II) complexes, [Cu(NO3)2(4,7-Hphen)2](NO3)2 (1) and [Cu(CF3SO3)(4,7- phen)2(H2O)2]CF3SO3 (2), were formed. On the other hand, in the reaction of CuX2 salts with 1,7-phen, only 1,7-HphenNO3 (3a/b) and 1,7-HphenCF3SO3 (4) were obtained as the final products. The obtained products 1–4 were characterized by spectroscopic and X-ray diffraction techniques. In the copper(II) complexes 1 and 2, the coordination geometry around the Cu(II) ion is distorted octahedral and square pyramidal, respectively. The antimicrobial potential of the copper(II) complexes 1 and 2 and corresponding compounds used for their synthesis were assessed against four different bacterial species and Candida albicans, displaying moderate growth inhibiting activity. The cytotoxic properties of the investigated complexes were also evaluated against the normal human lung fibroblast cell line (MRC-5) indicating moderate, yet more pronounced cytotoxicity than antimicrobial properties

Genomics-Based Insights Into the Biosynthesis and Unusually High Accumulation of Free Fatty Acids by Streptomyces sp NP10

Schneider O, Ilic-Tomic T, Rückert C, et al. Genomics-Based Insights Into the Biosynthesis and Unusually High Accumulation of Free Fatty Acids by Streptomyces sp NP10. FRONTIERS IN MICROBIOLOGY. 2018;9: 10.Streptomyces sp. NP10 was previously shown to synthesize large amounts of free fatty acids (FFAs). In this work, we report the first insights into the biosynthesis of these fatty acids (FAs) gained after genome sequencing and identification of the genes involved. Analysis of the Streptomyces sp. NP10 draft genome revealed that it is closely related to several strains of Streptomyces griseus. Comparative analyses of secondary metabolite biosynthetic gene clusters, as well as those presumably involved in FA biosynthesis, allowed identification of an unusual cluster C12-2, which could be identified in only one other S. griseus-related streptomycete. To prove the involvement of identified cluster in FFA biosynthesis, one of its three ketosynthase genes was insertionally inactivated to generate mutant strain mNP10. Accumulation of FFAs in mNP10 was almost completely abolished, reaching less than 0.01% compared to the wild-type strain. Cloning and transfer of the C12-2 cluster to the mNP10 mutant partially restored FFA production, albeit to a low level. The discovery of this rare FFA biosynthesis cluster opens possibilities for detailed characterization of the roles of individual genes and their products in the biosynthesis of FFAs in NP10

Expression and purification of the Sgm protein from E. coli

The sgm gene from Micromonospora zionensis, the producer of the aminoglycoside antibiotic G-52, encodes for Sgm methylasewhich modifies the target site on 16S rRNA and thus protects the producer against its own toxic product. The sgm gene wasmodified by polymerase chain reaction (PCR) and cloned in the QIAexpress pQE-30 vector in order to make a construct that places the (His)6 tag at the N-terminus of the protein. The resulting expression construct was transformed in the E. coli strain NM522 and the functional activity of the Sgm-His fusion protein was confirmed in vivo. Purification of the (His)6-tagged Sgm protein by Ni-NTA affinity chromatography was performed under native conditions and the protein was detected on a sodium dodecyl sulfate polyacrylamide gel. Sgm methylase was purified to homogeneity > 95 %. Polyclonal antibodies raised to purified (His)6-tagged Sgm protein were used to identify this protein byWestern blot analysis

Expression and purification of the Sgm protein from E. coli

The sgm gene from Micromonospora zionensis, the producer of the aminoglycoside antibiotic G-52, encodes for Sgm methylasewhich modifies the target site on 16S rRNA and thus protects the producer against its own toxic product. The sgm gene wasmodified by polymerase chain reaction (PCR) and cloned in the QIAexpress pQE-30 vector in order to make a construct that places the (His)6 tag at the N-terminus of the protein. The resulting expression construct was transformed in the E. coli strain NM522 and the functional activity of the Sgm-His fusion protein was confirmed in vivo. Purification of the (His)6-tagged Sgm protein by Ni-NTA affinity chromatography was performed under native conditions and the protein was detected on a sodium dodecyl sulfate polyacrylamide gel. Sgm methylase was purified to homogeneity > 95 %. Polyclonal antibodies raised to purified (His)6-tagged Sgm protein were used to identify this protein byWestern blot analysis

Specific approach for continuous air quality monitoring

Rapid industry development as well as increase of traffic volume across the world have resulted in air quality becoming one of the most important factors of everyday life. Air quality monitoring is the necessary factor for proper decision making regarding air pollution. An integral part of such investigations is the measurement of wind characteristics, as the wind is the most influential factor in turbulent pollution diffusion into the atmosphere. The most of the air pollution originates from combustion processes, so it is important to make quantitative, as well as qualitative analysis, as the sources of pollution can be very distant. In this paper, specific methodology for continuous wind, temperature and air quality data acquisition is presented. Comparison of the measured results is given, as well as the detailed presentation of the characteristics of the acquisition software used