Avian pathogenic Escherichia coli (APEC) is a major pathogen that causes avian colibacillosis and is associated with severe economic losses in the chicken-farming industry. Here, bacteriophage ...KBNP1315, infecting APEC strain KBP1315, was genomically and functionally characterized. The evolutionary relationships of KBNP1315 were analyzed at the genomic level using gene (protein)-sharing networks, the Markov clustering (MCL) algorithm, and comparative genomics. Our network analysis showed that KBNP1315 was connected to 30 members of the Autographivirinae subfamily, which comprises the SP6-, T7-, P60-, phiKMV-, GAP227- and KP34-related groups. Network decomposition suggested that KBNP1315 belongs to the SP6-like phages, but our comparison of putative encoded proteins revealed that key proteins of KBNP1315, including the tail spike protein and endolysin, had relative low levels of amino acid sequence similarity with other members of the SP6-like phages. Thus KBNP1315 may only be distantly related to the SP6-like phages, and (based on the difference in endolysin) its lysis mechanism may differ from theirs. To characterize the lytic functions of the holin and endolysin proteins from KBNP1315, we expressed these proteins individually or simultaneously in E. coli BL21 (DE3) competent cell. Interestingly, the expressed endolysin was secreted into the periplasm and caused a high degree of host cell lysis that was dose-dependently delayed/blocked by NaN3-mediated inhibition of the SecA pathway. The expressed holin triggered only a moderate inhibition of cell growth, whereas coexpression of holin and endolysin enhanced the lytic effect of endolysin. Together, these results revealed that KBNP1315 appears to use a pin-holin/signal-arrest-release (SAR) endolysin pathway to trigger host cell lysis.
The varistor characteristics of 0.1–3.0 at. % Co-doped ZnO have been investigated. Three kinds of deep bulk trap levels of 0.16, 0.25, and ~0.31 eV were identified as donor levels by admittance ...spectroscopy. Oxygen vacancy (
V
o
·
) appeared preferentially in 0.5–3.0 at. % Co-doped ZnO. From
J-E
characteristics nonohmic behavior was seen in this binary system while the nonlinear coefficient α changed between 3 and 35 depending on the composition. For 1.0 at. % Co-doped ZnO, two distinguishable activation energies of 0.65 eV and 1.04 eV related with grain boundary phenomena were confirmed above and below ~520 K by impedance and modulus spectroscopy. It is believed that the varistor behavior of Co-doped ZnO stems from the formation of double Schottky barrier by the valence change of Co ions in ZnO grains as well as oxygen chemisorption at the grain boundaries on heating and subsequent cooling.
A Ru(2,2'-bipyridine-4,4'-dicarboxylic acid)2(NCS)2 RuL2(NCS)2/di-(3-aminopropyl)-viologen (DAPV)/tin oxide (SnO2) system was prepared and applied to extensive photocurrent generation with its ...maximum surface area. The SnO2 thin films on tin-doped indium oxide (ITO) were prepared using the chemical bath deposition method. Then, RuL2(NCS)2/DAPV on SnO2/ITO was easily prepared using self-assembled monolayers (SAMs). The photocurrent measurement of the system showed an excellent photocurrent of 20 nA cm-2 under the air mass 1.5 conditions (100 mW cm-2), which was increased by a factor of four compared to ones without SnO2 layers.
In the microwave and radio frequency (RF) plasma catalytic reaction at room temperature, the oxidative coupling of methane (OCM) over transitional metals loaded on ZSM-5 has been carried out. The ...transitional metals, Fe, Ni, Co and Cu (1B family element), loaded on ZSM-5 have been tested for the OCM using the plasma catalytic reaction. In this work, the conversion of methane to C2 products has been improved without the carbon deposition when the oxygen as a co-reactant gas was supplied. The order of the catalysts of higher conversion to C2 products in the microwave plasma reaction with plasma power of 120
W is Co–ZSM-5>Fe–ZSM-5≒Cu–ZSM-5>Ni–ZSM-5. Selectivity to ethylene is as high as 29.8%, to ethane 10% and to acetylene 49.9% and conversion of methane was as high as about 54.9% with pressure of 5–10
Torr, total flow rate of 125
ml/min and a methane/oxygen ratio of 4:1 over Co–ZSM-5. It is suggested that the catalyst may provide an active site for combination of radicals. It was found that yield of C2 products has been enhanced in the microwave plasma catalytic reaction, as microwave plasma system of high frequency has better energy efficiency than RF plasma system of low frequency.
Photoluminescence and photocurrent characteristics of Eu activated MAl2O4 (M = Ba, Ca, Sr) phosphors during and after Ultraviolet ray and visible light irradiation have been investigated. The ...photoluminescence (PL) and the photocurrent (PC) of the phosphors, in order to elucidate the relationship between the PL and the PC, were measured simultaneously on the same samples within a specially designed measuring box. Composition effects, such as a presence of Dy as a co-activator and Al-rich composition on the PL and PC characteristics have been investigated. Also, sensing characteristics on UV and visual light have been tested.
The ordering behaviour of Ba(Mg
1/3Nb
2/3)O
3 ceramics (BMN) substituted by La
3+, Na
+, K
+ was investigated using X-ray powder diffraction and transmission electron microscopy. The 1:2 ordered ...structure of BMN can be transformed to 1:1 ordered structure by substituting a small amount of La cation ion into the A-site. Moreover, the degree of ordering was increased with La content in the compound, and reached almost unity at La
=
50
mol%. When the La ion in (Ba
1−
x
La
x
)(Mg
(1+
x)/3
Nb
(2−
x)/3
)O
3 (BLMN) was substituted by Na or K ions, the 1:1 ordered structure of BLMN was transformed into the 1:2 ordered structure. The degree of 1:2 ordering was influenced by the sintering temperature and the size difference between the A and B site ions.
Transparent p-type semiconducting SrCu2O2 films have been deposited by RF magnetron sputtering under unbalanced bipolar pulsed DC bias on low-alkali glass substrates in a mixed gas of 1% H2/Ar below ...400 degrees C. The pulsed DC bias voltages to substrate were varied from 0 V to -200 V with a frequency of 350 kHz. The effect of pulsed DC bias on the structure and electrical and optical properties of SrCu2O2 films has been investigated using SEM, XRD, surface profiler, Hall measurements and UV-VIS spectrometer. The deposition rates of SrCu2O2 films under DC-pulsed bias show a maximum at -100 V bias, and decreased with increasing the bias voltage. XRD results of the as-deposited films under the bias voltage at 400 degrees C reveal SrCu2O2 polycrystalline phase, and increased crystallite size with increasing pulsed DC bias voltage. The SrCu2O2 films deposited under the pulsed-bias of -100 V exhibits the highest conductivity of 0.08 S/cm, and over 70% of transmittance at 550 nm. It is confirmed that the application of pulsed DC bias in sputtering improves the crystallization, crystal growth, and the electrical and optical properties eventually under 400 degrees C.
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