Malondialdehyde level and some enzymatic activities in subclinical mastitis milk

The purpose of this study was to evaluate the changes occurring in milk malondialdehyde (MDA) level and some enzymatic activities as a result of subclinical mastitis (SCM) in dairy cows. A total of 124 milk samples were collected from 124 lactating cows from the same herd in the period between the 2nd week after calving and the 10th week postpartum. They were classified by bacterial culture and the California mastitis test (CMT) as positive were deemed to have glands with SCM, and the periodic incidence rate of SCM was 26.6%. The most common bacterial isolates from SCM cases were Staphylococcus aureus (47%) and coagulase negative Staphylococci (CNS) (27%). The mean level of MDA and activities of lactate dehydrogenase (LDH) and alkaline phosphatase (ALP) were significantly higher in SCM milk than in normal milk, while the mean activity of glutathione peroxidase (GPx) was significantly lower in SCM milk than in normal milk. There were no differences in the activities of superoxide dismutase (SOD) and aspartate aminotransferase (AST) between normal milk and SCM milk. Therefore, the measurement of milk MDA level and GPx, LDH and ALP activities, appears to be a suitable diagnostic method for identifying SCM in dairy cows.Key words: Subclinical mastitis, mastitis diagnostic, etiology, malonaldehyde (MDA), enzym

T-DNA integration patterns in transgenic maize lines mediated by Agrobacterium tumefaciens

To explore transfer deoxyribonucleic acid (T-DNA) integration patterns in the maize genome, we improved the protocol of thermal asymmetric interlaced polymerase chain reaction (TAIL-PCR), and amplified the flanking sequences around T-DNA integration sites from 70 independent transgenic maize lines mediated by Agrobacterium tumefaciens. Out of 64 specific amplified fragments, 32 and 9 are homologous to the sequences of the maize genome and the expression plasmid, respectively. For 26 of them, a filler sequence was found flanking the cleavage sites. These results demonstrate that cleavage occurs not only during the T-DNA borders but also inside or outside the borders. The border sequences and some inside sequences can be deleted, and filler sequences can be inserted. Illegitimate recombination is a major pattern of T-DNA integration, while some hot spots and preference are present on maize chromosomes.Key words: Agrobacterium tumefaciens, maize, thermal asymmetric interlaced PCR, transfer DNA,transgenics

Antisense-induced suppression of taxoid 14β- hydroxylase gene expression in transgenic Taxus × media cells

The enzyme taxoid 14β-hydroxylase (14OH) directs a side-route of taxol pathway to 14β-hydroxy taxoids. Suppression of this side-route could increase the production of taxol. To suppress taxoid 14β- hydroxylase gene (14OH) expression in the Taxus × media TM3 cell line, antisense RNA inhibition approach was used in this study. Following the construction of an antisense RNA expression vector of 14OH from Taxus chinensis, the antisense 14OH cDNA (as14OH) was introduced into TM3 cells by Agrobacterium tumefaciens-mediated transformation. Southern blot analysis of hygromycin phosphotransferase gene (HYG) revealed that this selection gene was integrated successfully into the genome of Taxus × media cells. Reverse transcription-polymerase chain reaction (RT-PCR) analysis showed that the 14OH mRNA level in transgenic cells dropped dramatically, suggesting that the expression of endogenous14OH gene was significantly suppressed by the exogenous as14OH gene. Correspondingly, the total yield of three major C-14 oxygenated taxoids (yunnanxane, taxuyunnanine C, sinenxan C) was markedly reduced in the silenced cell lines when compared with those of the nontransgenic controls. These results indicated that the antisense RNA strategy is a useful tool in suppressing the expression of genes in Taxus and this method could be used to silence other important genes that divert Taxol pathway to side-route metabolites.Key words: Taxus × media, taxoid 14β-hydroxylase, antisense, gene suppression

En-situ EXAFS investigation of zeolite supported Pt electrocatalyst structure

Experimental investigation was carried out for Pt electrochemical performance and Pt particle size using 1.5 wt% and 5 wt% Pt loading on zeolite electrocatalysts made by Pt(NH3)4(NO3)2 or Pt(NH3)4(NO3)2/NH4NO3 salt with ion exchanged method and calcined at 350 oC and reduced at 400 oC or direct reduced at 400 oC, respectively. Cyclic voltammetry measurement indicated that the hydrogen energy binding level on Pt surfaces is higher for electrocatalyst under direct reduction process than those made by calcination and reduction process. The extended X-ray adsorption fine structure measurement revealed that Pt size for electrocatalyst made by calcination and reduction method is smaller than those made by direct reduced method. Furthermore, Pt size for electrocatalysts with 1.5 wt% Pt loading on zeolite is smaller compared to those with 5 wt% Pt loading electrocatalysts. Aforementioned electrochemical performance of Pt zeolite electrocatalysts has depicted by a hypothesis of hydrogen spillover and surface conductance pathway

Lightweight and highly conductive silver nanoparticles functionalized meta-aramid nonwoven fabric for enhanced electromagnetic interference shielding

High-performance electromagnetic interference (EMI) shielding material that that can function properly under extreme working conditions is critical for their practical applications. Herein, flexible and highly conductive meta-aramid (PMIA) nonwoven fabrics were fabricated by combining polydopamine (PDA) modification and electroless silver plating. The PDA modification greatly enhanced the efficient deposition of silver nanoparticles (AgNPs) and the interfacial cohesion between the AgNPs and the PMIA fibers. The silver-coated PMIA nonwoven fabric exhibited an electrical conductivity as high as 0.29 Ω/sq, an excellent EMI shielding effectiveness (SE) of 92.6 dB and a high absolute EMI SE of 8194.7 dB cm^{2} g^{−1}. In addition, the silver-coated PMIA nonwoven fabric maintained high electrical conductivity and EMI SE after being subjected to washing, bending and torsion deformations, high/low temperature, strong acidic/alkaline solutions and different organic solvents. These results have clearly demonstrated that PMIA nonwoven fabric can be made highly electrically conductive by using a simple and highly scalable method. It holds great promise for the applications in EMI shielding materials that can be used in various harsh conditions

Flexible and Highly Conductive AgNWs/PEDOT:PSS Functionalized Aramid Nonwoven Fabric for High-Performance Electromagnetic Interference Shielding and Joule Heating

High-performance multifunctional textiles are highly demanded for human health-related applications. In this work, a highly conductive nonwoven fabric is fabricated by coating silver nanowires (AgNWs)/poly(3,4-ethyl enedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) on a poly(m-phenylene isophthalamide) (PMIA) nonwoven fabric through a multistep dip coating process. The as-prepared PMIA/AgNWs/PEDOT:PSS composite nonwoven fabric shows an electrical resistance as low as 0.92 ± 0.06 Ω sq−1 with good flexibility. The incorporation of the PEDOT:PSS coating layer improves the adhesion between AgNWs and PMIA nonwoven fabric, and also enhances the thermal stability of the composite nonwoven fabric. Electromagnetic interference (EMI) shielding and Joule heating performances of the PMIA/AgNWs/PEDOT:PSS composite nonwoven fabric are also investigated. The results show that the average EMI shielding effectiveness (SE) of the single-layer nonwoven fabric in X-band is as high as 56.6 dB and retains a satisfactory level of SE after being washed, bended, and treated with acid/alkali solution and various organic solvents. The composite nonwoven fabric also exhibits low voltage-driven Joule heating performance with reliable heating stability and repeatability. It can be envisaged that the multifunctional PMIA/AgNWs/PEDOT:PSS nonwoven fabric with reliable stability and chemical robustness can be used in EMI shielding devices and personal thermal management products

Fluorine-Free Transparent Superhydrophobic Nanocomposite Coatings from Mesoporous Silica

In recent decades, there has been a growing interest in the development of functional, fluorine-free superhydrophobic surfaces with improved adhesion for better applicability into real-world problems. Here, we compare two different methods, spin coating and aerosol-assisted chemical vapor deposition (AACVD), for the synthesis of transparent fluorine-free superhydrophobic coatings. The material was made from a nanocomposite of (3-aminopropyl)triethoxysilane (APTES) functional mesoporous silica nanoparticles and titanium cross-linked polydimethylsiloxane with particle concentrations between 9 to 50 wt %. The silane that was used to lower the surface energy consisted of a long hydrocarbon chain without fluorine groups to reduce the environmental impact of the composite coating. Both spin coating and AACVD resulted in the formation of superhydrophobic surfaces with advancing contact angles up to 168°, a hysteresis of 3°, and a transparency of 90% at 550 nm. AACVD has proven to produce more uniform coatings with concentrations as low as 9 wt %, reaching superhydrophobicity. The metal oxide cross-linking improves the adhesion of the coating to the glass. Overall, AACVD was the more optimal method to prepare superhydrophobic coatings compared to spin coating due to higher contact angles, adhesion, and scalability of the fabrication process

The Kaon-Photoproduction Of Nucleons In The Quark Model

In this paper, we develop a general framework to study the meson-photoproductions of nucleons in the chiral quark model. The S and U channel resonance contributions are expressed in terms of the Chew-Goldberger-Low-Nambu (CGLN) amplitudes. The kaon-photoproduction processes, $\gamma p\to K^+ \Lambda$, $\gamma p\to K^+ \Sigma^0$, and $\gamma p\to K^0\Sigma^+$, are calculated. The initial results show that the quark model provides a much improved description of the reaction mechanism for the kaon-photoproductions of the nucleon with less parameters than the traditional phenomenological approaches.Comment: 25 pages, 9 postscript figures can be obtained from the author

The Threshold Pion-Photoproduction of Nucleons In The Chiral Quark Model

In this paper, we show that the low energy theorem (LET) of the threshold pion-photoproduction can be fully recovered in the quark model. An essential result of this investigation is that the quark-pion operators are obtained from the effective chiral Lagrangian, and the low energy theorem does not require the constraints on the internal structures of the nucleon. The pseudoscalar quark-pion coupling generates an additional term at order $\mu=m_{\pi}/M$ only in the isospin amplitude $A^{(-)}$. The role of the transitions between the nucleon and the resonance $P_{33}(1232)$ and P-wave baryons are also discussed, we find that the leading contributions to the isospin amplitudes at $O(\mu^2)$ are from the transition between the P-wave baryons and the nucleon and the charge radius of the nucleon. The leading contribution from the P-wave baryons only affects the neutral pion production, and improve the agreement with data significantly. The transition between the resonance $P_{33}(1232)$ and the nucleon only gives an order $\mu^3$ corrections to $A^{(-)}$