Formation of ZnO Micro-Flowers Prepared via Solution Process and their Antibacterial Activity

This paper presents the fabrication and characterization of zinc oxide micro-flowers and their antibacterial activity. The micro-flowers of zinc oxide composed of hexagonal nanorods have been prepared via solution process using precursor zinc acetate di-hydrate and sodium hydroxide in 3 h of refluxing time at ~90°C. The antibacterial activities of grown micro-flowers were investigated against four pathogenic bacteria namely S. aureus, E. coli, S. typhimurium and K. pneumoniae by taking five different concentrations (5–45 μg/ml) of ZnO micro-flowers (ZnO-MFs). Our investigation reveals that at lowest concentration of ZnO-MFs solution inhibiting the growth of microbial strain which was found to be 5 μg/ml for all the tested pathogens. Additionally, on the basis of morphological and chemical observations, a chemical reaction mechanism of ZnO-MFs composed of hexagonal nanorods was also proposed

Synthesis, characterization and effect of pH variation on zinc oxide nanostructures

Here we present a systematic study on the morphological deviation of ZnO nanostructure (from sheets to micro-flowers) by varying pH of the solution via precipitation method. In this regard, zinc nitrate hexa-hydrate, NaOH and hydroxylamine hydrochloride (NH 2 OHÁHCl) were used. The solution of all three compounds was refluxed at a very low temperature (60 C) for short time (20 min). The solution pH was calibrated from 6 to 12 by the controlled addition of NaOH and HCl. We have observed from FESEM (field emission scanning electron microscopy) that the morphology of ZnO microballs composed with thin sheets markedly varies from sheet (at pH ¼ 6) to micro-flower composed with sheets of zinc oxide (pH ¼ 10{12). Further the morphology and crystallinity were also studied by the TEM (transmission electron microscopy) and HR-TEM (High resolution transmission electron microscopy) and it's clearly consistent with the FESEM observations. The FTIR spectroscopic measurement also confirms the compositional analysis of ZnO and it comes in the range of 475 to 424 cm À1 which is a standard peak of ZnO. In addition to this, the amount of H þ and OH À ions are found a key to control the structure of studied material and discussed in the growth mechanism

System Coverage and Capacity Analysis on Millimeter-Wave Band for 5G Mobile Communication Systems with Massive Antenna Structure

The use of a millimeter-wave band defined as a 30–300 GHz range is significant element for improving performance of 5th generation (5G) mobile communication systems. However, since the millimeter-wave signal has peculiar propagation characteristics especially toward non-line-of-sight regions, the system architecture and antenna structure for 5G mobile communications should be designed to overcome these propagation limitations. For realization of the 5G mobile communications, electronics and telecommunications research institute (ETRI) is developing central network applying various massive antenna structures with beamforming. In this paper, we have introduced the central network and evaluated the system coverage and capacity through C++ language-based simulations with real geospatial information

The Prevalence of Hepatitis C Virus Infection in Korea: Pooled Analysis

This study evaluated the prevalence of hepatitis C virus (HCV) infections in Korea. Pooled estimates of the anti-HCV positivity were calculated using the data published in 15 reports on the general population and health check-up examinees. The overall pooled estimate of the prevalence of HCV among middle-aged adults (40 yr old and above) was 1.68% (95% confidence interval: 1.51-1.86%) during the year of 1990-2000 among the general population. Most of the published data indicated that the prevalence of anti-HCV increased with age. The anti-HCV positivity was significantly higher in females than in males. Because the risk of HCV exposure in blood recipients has decreased remarkably, the spread of HCV through means other than a transfusion must be prevented

The lipoxygenase gene family: a genomic fossil of shared polyploidy between Glycine max and Medicago truncatula

<p>Abstract</p> <p>Background</p> <p>Soybean lipoxygenases (<it>Lxs</it>) play important roles in plant resistance and in conferring the distinct bean flavor. <it>Lxs </it>comprise a multi-gene family that includes <it>GmLx1</it>, <it>GmLx2 </it>and <it>GmLx3</it>, and many of these genes have been characterized. We were interested in investigating the relationship between the soybean lipoxygenase isozymes from an evolutionary perspective, since soybean has undergone two rounds of polyploidy. Here we report the tetrad genome structure of soybean <it>Lx </it>regions produced by ancient and recent polyploidy. Also, comparative genomics with <it>Medicago truncatula </it>was performed to estimate <it>Lxs </it>in the common ancestor of soybean and <it>Medicago</it>.</p> <p>Results</p> <p>Two <it>Lx </it>regions in <it>Medicago truncatula </it>showing synteny with soybean were analyzed. Differential evolutionary rates between soybean and <it>Medicago </it>were observed and the median Ks values of Mt-Mt, Gm-Mt, and Gm-Gm paralogs were determined to be 0.75, 0.62, and 0.46, respectively. Thus the comparison of Gm-Mt paralogs (Ks = 0.62) and Gm-Mt orthologs (Ks = 0.45) supports the ancient duplication of <it>Lx </it>regions in the common ancestor prior to the <it>Medicago</it>-<it>Glycine </it>split. After speciation, no <it>Lx </it>regions generated by another polyploidy were identified in <it>Medicago</it>. Instead tandem duplication of <it>Lx </it>genes was observed. On the other hand, a lineage-specific duplication occurred in soybean resulting in two pairs of <it>Lx </it>regions. Each pair of soybean regions was co-orthologous to one <it>Lx </it>region in <it>Medicago</it>. A total of 34 <it>Lx </it>genes (15 <it>MtLxs </it>and 19 <it>GmLxs) </it>were divided into two groups by phylogenetic analysis. Our study shows that the <it>Lx </it>gene family evolved from two distinct <it>Lx </it>genes in the most recent common ancestor.</p> <p>Conclusion</p> <p>This study analyzed two pairs of <it>Lx </it>regions generated by two rounds of polyploidy in soybean. Each pair of soybean homeologous regions is co-orthologous to one region of <it>Medicago</it>, demonstrating the quartet structure of the soybean genome. Differential evolutionary rates between soybean and <it>Medicago </it>were observed; thus optimized rates of Ks per year should be applied for accurate estimation of coalescence times to each case of comparison: soybean-soybean, soybean-<it>Medicago</it>, or <it>Medicago</it>-<it>Medicago</it>. In conclusion, the soybean <it>Lx </it>gene family expanded by ancient polyploidy prior to taxon divergence, followed by a soybean- specific duplication and tandem duplications, respectively.</p

Leukotactin-1/CCL15-induced chemotaxis signaling through CCR1 in HOS cells

AbstractLeukotactin-1 (Lkn-1)/CCL15 is a recently cloned CC-chemokine that binds to the CCR1 and CCR3. Although Lkn-1 has been known to function as a chemoattractant for neutrophils, monocytes and lymphocytes, its cellular mechanism remains unclear. To understand the mechanism of Lkn-1-induced chemotaxis signaling, we examined the chemotactic activities of human osteogenic sarcoma cells expressing CCR1 in response to Lkn-1 using inhibitors of signaling molecules. Inhibitors of Gi/Go protein, phospholipase C (PLC) and protein kinase Cδ (PKCδ) inhibited the chemotactic activity of Lkn-1 indicating that Lkn-1-induced chemotaxis signal is transduced through Gi/Go protein, PLC and PKCδ. The activities of PLC and PKCδ were also enhanced by Lkn-1 stimulation. Chemotactic activity of Lkn-1 was inhibited by the treatment of cycloheximide and actinomycin D suggesting that newly synthesized proteins are needed for chemotaxis. Nuclear factor-κB (NF-κB) inhibitor reduced chemotactic activity of Lkn-1. DNA binding activity of NF-κB was also enhanced by Lkn-1 stimulation. These results suggest that Lkn-1 transduces the signal through Gi/Go protein, PLC, PKCδ, NF-κB and newly synthesized proteins for chemotaxis

Interfacial Reactions of Ozone with Surfactant Protein B in a Model Lung Surfactant System

Oxidative stresses from irritants such as hydrogen peroxide and ozone (O_3) can cause dysfunction of the pulmonary surfactant (PS) layer in the human lung, resulting in chronic diseases of the respiratory tract. For identification of structural changes of pulmonary surfactant protein B (SP-B) due to the heterogeneous reaction with O_3, field-induced droplet ionization (FIDI) mass spectrometry has been utilized. FIDI is a soft ionization method in which ions are extracted from the surface of microliter-volume droplets. We report structurally specific oxidative changes of SP-B_(1−25) (a shortened version of human SP-B) at the air−liquid interface. We also present studies of the interfacial oxidation of SP-B_(1−25) in a nonionizable 1-palmitoyl-2-oleoyl-sn-glycerol (POG) surfactant layer as a model PS system, where competitive oxidation of the two components is observed. Our results indicate that the heterogeneous reaction of SP-B_(1−25) at the interface is quite different from that in the solution phase. In comparison with the nearly complete homogeneous oxidation of SP-B_(1−25), only a subset of the amino acids known to react with ozone are oxidized by direct ozonolysis in the hydrophobic interfacial environment, both with and without the lipid surfactant layer. Combining these experimental observations with the results of molecular dynamics simulations provides an improved understanding of the interfacial structure and chemistry of a model lung surfactant system subjected to oxidative stress