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Iron oxidation and removal from groundwater is a necessary and costly process in drinking water production. In most cases, iron removal is done via aeration, succeeded by precipitation. Most systems for aeration are based on increasing the interfacial area via injecting air in the system or spraying. Both methods have disadvantages, like clogging and formation of aerosols. In this study, a new vortex-based flow-through reactor consisting of a cylindrical tank with an impeller located at the bottom was studied regarding its aeration and iron oxidation capabilities in groundwater. During the aeration experiments, the flow rate, impeller rotation and aerated volume were varied. A nondimensional constant α was proposed to relate the system’s physical characteristics and its aeration capabilities, expressed in dissolved oxygen and system volumetric mass transfer coefficient (KLa). Three distinct operational regimes were defined: formation, complete and bubble regime. These regimes showed very specific characteristics regarding the air–water interface structure and the area to volume ratio, resulting in different aeration capabilities and iron oxidation efficiency values. The system presented KLa values similar to commercially available aeration systems, especially inside the bubble regime. By using dimensionless coefficients, the presented analysis provided the basis for the design of continuous impeller aeration and oxidation systems of arbitrary size.

Superconducting photodetection offers a wide spectral coverage ranging from the microwave to X-ray, and in the short wavelength range, single photon sensitivity can be achieved. However, in the longer wavelength infrared region, the system detection efficiency is low due to the lower internal quantum efficiency and weak optical absorption. Here, we utilized the superconducting metamatieral to enhance the light coupling efficiency and reach nearly perfect absorption at dual color infrared wavelengths. Dual color resonances arise from hybridization of local surface plasmon mode of the metamaterial structure and the Fabry-Perot-like cavity mode of metal (Nb)-dielectric (Si)-metamatieral (NbN) tri-layer structure. We demonstrated that, at the working temperature of 8 K slightly below T C ∼8.8 K, this infrared detector exhibits the peak responsivity of 1.2 × 106 V/W and 3.2 × 106 V/W at two resonant frequencies 36.6 THz and 104 THz, respectively. The peak responsivity is enhanced about ∼8 and ∼22 times, respectively, compared to that of non-resonant frequency (67 THz). Our work provides a way to harvest infrared light efficiently and hence improve the sensitivity of superconducting photodetectors in multispectral infrared range, which may find promising applications in thermal image and gas sensing etc.

BackgroundPogostemon cablin is a traditional Chinese medicine (TCM) that is frequently used to treat various gastrointestinal diseases. Patchouli alcohol (PA), a compound extracted from the Pogostemon cablin, has been shown to have anti-tumor efficacy in human colorectal cancer. However, the mechanism of PA’s anticancer effect on gastric cancer (GC) remains unknown.MethodsWe used the public database to obtain the potential targets of PA and genes related to GC. Bioinformatic analyses, such as the Kyoto Encyclopedia of Genes and Genomes (KEGG), Gene Ontology (GO), and protein-protein interactions (PPI), were used for analyzing the potential signal pathways and targets. Cell experiments were also conducted to further explain the impact and molecular mechanism of PA on GC, as well as to confirm the findings of network pharmacology.ResultsUsing network pharmacological analysis, 161 possible targets were identified for the treatment of GC. Network analysis and functional enrichment analysis show that PA produced a marked effect in the treatment of GC through multi-targets and multi-pathways, especially the MAPK and PI3K/AKT signal pathways. In addition, PA showed the inhibition of GC cell proliferation, migration and invasion in cell experiments. According to our findings, PA could also cause G0/G1 phase arrest and apoptosis in GC cells.ConclusionUsing network pharmacology, we aim to uncover the possible molecular mechanism of PA on GC treatment in this research. Cell experiments were also conducted to confirm the therapeutic effect of PA on GC.

Background Qianjinweijing Tang (QJWJ) is a classic traditional Chinese formula that is often used in the treatment of treat lung cancer (LC). However, the underlying cellular mechanisms of the anticancer effects of QJWJ remain unclear. Methods Cell viability was determined by MTS assay and levels of apoptosis measured by flow cytometry. Animal experiments were conducted to determine the effects of QJWJ on tumour growth in vivo. We used a proteomics approach to study the effects of QJWJ on LC cells and applied bioinformatics analysis to identify differentially expressed proteins that were validated by Western blotting. Results QJWJ inhibited the proliferation of LC cells and induced apoptosis. The tumour growth delay effects of QJWJ were confirmed in vivo. We identified 104 differentially expressed proteins following QJWJ treatments of which 45 proteins were upregulated and 59 proteins were downregulated. The levels of differentially expressed proteins were validated by Western blotting. Conclusion Our study indicated that QJWJ has anticancer effects in vivo and in vitro and that these effects are mediated by modulating the expression of tumour-related proteins.

Background: Modern pharmacological studies have shown that traditional Chinese medicine (TCM) Taraxacum mongolicum possesses anti-cancer activity. Taraxerol (TRX) is a pentacyclic triterpene isolated from T. mongolicum, which is widely used in clinical treatment, and its anti-cancer effects have been extensively studied. However, the effects and molecular mechanism of TRX in gastric cancer (GC) have not been fully explicated. Methods: We used public databases to derive information on potential targets of TRX and proteins related to GC. Also, STRING and R3.6.2 software were used to analyze the protein–protein interaction (PPI). The Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses were done to explain the potential mechanism underlying the regulatory role of TRX in GC. The role of TRX in GC was verified by 3-(4,5)-dimethylthiahiazo (-z-y1)-3,5-di- phenytetrazoliumromide (MTT) assay, apoptosis analysis, Transwell assay, and wound healing assay, and the key signaling pathways were verified. Results: We identified 135 potential targets for the treatment of GC via network pharmacological analysis. GO and KEGG enrichment analysis showed that steroid hormone receptor activity and the PI3K/AKT signaling pathway were the biological processes and pathways with the highest degree of enrichment. Additionally, cellular experiments revealed that TRX inhibited the proliferation, migration, and invasion of GC cells as well as induced G1 phase arrest and apoptosis in GC cells. Conclusion: Here, we used multi-target and multi-pathway network pharmacological analysis to verify the anti-cancer activity of TRX in GC. Also, in vitro experimental data were used to derive the potential molecular mechanism.

Particulate Matters such as PM10, PM2.5 may contain heavy metal oxides and harmful substances that threaten human health and environmental quality. In this paper, we propose a new combined neural n...

Particulate Matters such as PM

We report on the status of an ongoing effort to develop arrays of horn-coupled, polarization-sensitive microwave kinetic inductance detectors (MKIDs) that are each sensitive to two spectral bands between 125 and 280 GHz. These multi-chroic MKID arrays are tailored for next-generation, large-detector-count experiments that are being designed to simultaneously characterize the polarization properties of both the cosmic microwave background (CMB) and Galactic dust emission. We present our device design and describe laboratory-based measurement results from two 23-element prototype arrays. From dark measurements of our first engineering array we demonstrated a multiplexing factor of 92, showed the resonators respond to bath temperature changes as expected, and found that the fabrication yield was 100%. From our first optically loaded array we found the MKIDs respond to millimeter-wave pulses, additional optical characterization measurements are ongoing. We end by discussing our plans for scaling up this technology to kilo-pixel arrays over the next two years., LTD-17 paper accepted by Journal of Low Temperature Physics

In order to investigate partial melting and melt evolution during exhumation of deeply subducted continental crust, we carried out a combined study on layered leucosomes and pegmatitic veins from the Weihai–Rongcheng migmatites in the Sulu ultra-high pressure (UHP) metamorphic terrane, eastern China. The leucosomes are millimetric to centimetric in thickness and mainly consists of K-feldspar + quartz + plagioclase. The pegmatitic veins emplace along the compositional layers or crosscut them and are mainly composed of K-feldspar + quartz. CL images show that most zircon grains of the leucosomes have a core–rim zoning structure, whereas zircons of the pegmatitic veins are mostly new growth grains with rarely preserved relict domains. The inherited zircon domains (ca. 750 Ma) are of a magmatic origin with zircon eHf(t) values between − 5.7 and 5.3 (mean = − 0.8 ± 1.5), suggesting that the protolith rock is a Mid-Neoproterozoic juvenile crust. The zircon overgrowth rims (223 ± 3 Ma) of the leucosomes and the new zircon grains (217 ± 2 Ma) of the pegmatitic veins formed in equilibrium with melt and are similar to magmatic zircons in terms of their CL images and trace element compositions, e.g., heavy-enriched REE patterns (i.e., very low (Gd/Lu)N ratios) with positive Ce and variably negative Eu anomalies, high Y contents and low Hf/Y ratios. Compared with the inherited protolith zircon domains, the Triassic zircon domains of the leucosomes and the pegmatitic veins have obviously high U but low Th contents, resulting in very low Th/U ratios (

Chrysanthemums host many viruses, viroid species, and sequence variants thereof. In the present study, a stem apex detoxification culture system for chrysanthemum ‘YUTAI’, a cultivar used for chrysanthemum tea, was established by apical meristem culture in vitro on basal Murashige and Skoog medium supplemented with 0.5 mg L−1 benzyladenine and 0.1 mg L−1 naphthalene acetic acid (NAA) to stimulate shooting, and on medium containing 0.5 mg L−1 NAA to afford the highest frequency of rooting. Seven viruses [Chrysanthemum stunt viroid (CSVd), Chrysanthemum chlorotic mottle viroid (CChMVd), Chrysanthemum virus B, Cucumber mosaic virus, Tobacco mosaic virus, Tomato spotted wilt virus, and Tomato aspermy virus] present in seedlings were synchronously detected using a sensitive multiplex reverse transcription-polymerase chain reaction assay. Two of these viruses (CChMVd and CSVd) compromised plant growth and development (affecting both the photosynthetic rate and height attained), and their levels were investigated in annual plants. Compared with seedlings infected by either or both CChMVd and CSVd, the chlorophyll content, the net photosynthetic rate, and the stomatal conductance and transpiration rates were higher, but the concentration of intercellular CO2 slightly lower, in virus-free seedlings. Virus-infected seedlings were stunted, exhibiting a reduction of 27 % of the mean height of virus-free plants. We suggest that the lower net photosynthetic rate and stunted growth observed in virus-infected seedlings were caused by the virus-mediated degradation of leaf chlorophyll, which in turn compromised plant nutrition.

The Weihai migmatite in the Sulu ultra-high-pressure (UHP) metamorphic terrane, eastern China, underwent partial melting in the Late Triassic during its exhumation. The primary partial melts experienced a decompressional fractional crystallization (DFC) process to produce plagioclase (Pl)-rich leucosome crystallized under eclogite to granulite facies conditions and K-feldspar (Kfs)-rich pegmatitic veins crystallized under amphibolite-facies conditions. In this study, our results demonstrate that the DFC process can cause decoupling between whole-rock Sr and Nd isotopes. The Pl-rich leucosome has eNd(t) values (–10.4 to −15.0) and initial (87Sr/86Sr) ratios (0.708173–0.712476) very similar to those of the melanosome, but the Kfs-rich pegmatitic veins have homogeneous eNd(t) values (−14.8 to −15.2) and significantly high initial (87Sr/86Sr) ratios (0.713882–0.716284). Our results also suggest that the DFC process can change zircon 176Yb/177Hf and 176Lu/177Hf isotopic ratios, with no effect on 176Hf/177Hf ra...

Short-term load forecasting (STLF) plays a significant role in economic and social development. As a challenging but indispensable task, STLF has become a hot topic in the field of energy. However, the inadequacy of existing methods lies in their inability to capture accurate input features that are highly related to the output, as the main focus of research has been on improving the accuracy of STLF, while ignoring its stability. Therefore, in this paper, a novel, robust hybrid forecasting system was developed, composed of four modules: (1) data preprocessing, (2) forecasting, (3) optimization, and (4) evaluation. In the data preprocessing module, an effective data preprocessing scheme based on singular spectrum analysis and gray correlation analysis was used to produce a smoother time series and to mine the best input and output structure for the model. An extreme learning machine (ELM) optimized using a multiobjective genetic algorithm (MOGA) that considers both the forecasting accuracy and stability was employed to provide the forecasting. Additionally, a generalized regression neural network (GRNN) was also used in the subsequent module to perform forecasting. Moreover, to further obtain accurate results and to overcome the drawbacks of using single models, a simulated annealing (SA) algorithm was utilized to optimize the combined parameters of the MOGA–ELM and GRNN algorithms in the optimization module. To validate the proposed model, half-hourly load data from the New South Wales and Tasmania are provided as illustrative cases. The experimental results show that the proposed hybrid model obtains more accurate and stable results than the reference models used for comparison.

Water-sensitive components in asphalt are one of the main contributors to moisture damage to asphalt pavement. Solvent extraction was adopted in this research. The enrichment conditions and transformation of the water-sensitive components during pavement service were studied. The results showed that CS2 could completely extract water-sensitive components from asphalt-water emulsion. Among the two processes of the asphalt preparation with the same source petroleum, the amount of water-sensitive components was lower for the distillation method. The amount of water-sensitive components varies significantly during pavement service.

In order to decipher fluid/melt activity during subduction and subsequent exhumation of felsic continental crust, we carried out a combined study of zircon internal structure, zircon U–Pb age, zircon trace element composition and whole-rock geochemistry on migmatitic gneisses from the Weihai region in the Sulu ultra-high pressure (UHP) metamorphic terrane, eastern China. The Weihai migmatitic gneisses are composed of intercalated compositional layers of melanosome and plagioclase (Pl)-rich leucosome and K-feldspar (Kfs)-rich pegmatite veins. Whole-rock geochemistry suggests that MgO, Fe2O3T, CaO, TiO2, P2O5, rare earth elements (REE), and large ion lithophile elements (HFSE) are nearly completely retained in the melanosome, whereas significant amounts of LILE (e.g., Rb, Ba, K, Sr, Pb) and U are partitioned into the Pl-rich leucosome and the Kfs-rich pegmatite veins. The Kfs-rich pegmatite vein has much higher K2O, U, Pb and Rb, but lower CaO and Na2O contents than those of the Pl-rich leucosome layer. Protolith magmatic zircon domains, with an upper intercept age of about 780 Ma, are common in the cores of zircon grains from the melanosome and the Pl-rich leucosome layers, indicating that the protolith of the migmatitic gneiss is Mid-Neoproterozoic magmatic rock. Metamorphic zircons with concordant ages ranging from 243 to 256 Ma occur as overgrowth mantles on the protolith magmatic zircon cores. They are characterized by remarkably flat heavy rare earth element (HREE) patterns without obviously negative Eu anomalies, and have low Y and Th contents, low Th/U and high Hf/Y ratios, indicating a prograde metamorphism in the HP eclogite-facies during subduction. Recrystallized rims of zircons (228 ± 2 Ma) in the Pl-rich leucosome layer are similar to magmatic zircons in terms of their HREE enriched patterns with negative Eu anomalies, high Y and low Th contents, and low Hf/Y and Th/U ratios. This indicates that the gneiss has experienced decompressional partial melting and the Pl-rich leucosome layers were formed by fractional crystallization of the primary melt during the early stage hot exhumation. Zircon grains (219 ± 2 Ma) in the Kfs-rich veins are characterized by aqueous fluid/melt-related signatures with strongly HREE enriched patterns, high U, Pb and low Th contents, and low Th/U and high Lu/Hf ratios, indicating that the pegmatite vein was formed by crystallization of residual aqueous melt after the crystallization of Pl-rich leucosome layers during later stage cooling during exhumation. Our results suggest that the migmatitic gneiss successively recorded information concerning the protolith, prograde HP metamorphism during subduction, fractional crystallization of primary melt and crystallization of the residual melt during exhumation.

We report on the development of scalable prototype microwave kinetic inductance detector (MKID) arrays tailored for future multi-kilo-pixel experiments that are designed to simultaneously characterize the polarization properties of both the cosmic microwave background (CMB) and Galactic dust emission. These modular arrays are composed of horn-coupled, polarization-sensitive MKIDs, and each pixel has four detectors: two polarizations in two spectral bands between 125 and 280 GHz. A horn is used to feed each array element, and a planar orthomode transducer, composed of two waveguide probe pairs, separates the incoming light into two linear polarizations. Diplexers composed of resonant-stub band-pass filters separate the radiation into 125 to 170 GHz and 190 to 280 GHz pass bands. The millimeter-wave power is ultimately coupled to a hybrid co-planar waveguide microwave kinetic inductance detector using a novel, broadband circuit developed by our collaboration. Electromagnetic simulations show the expected absorption efficiency of the detector is approximately 90%. Array fabrication will begin in the summer of 2016., To appear in the Proc. SPIE

We present a two-step technique for the synthesis of superconducting CuxBi2Se3. Cu0.15Bi2Se3 single crystals were synthesized using the melt-growth method. Although these samples are non-superconducting, they can be employed to generate high quality superconducting samples if used as precursors in the following electrochemical synthesis step. Samples made from Cu0.15Bi2Se3 reliably exhibit zero-resistance even under the non-optimal quenching condition, while samples made from pristine Bi2Se3 require fine tuning of the quenching conditions to achieve similar performance. Moreover, under the optimal quenching condition, the average superconducting shielding fraction was still lower in the samples made from pristine Bi2Se3 than in the samples made from Cu0.15Bi2Se3. These results suggest that the pre-doped Cu atoms facilitate the formation of a superconducting percolation network. We also discuss the useful clues that we gathered about the locations of Cu dopants that are responsible for superconductivity., Comment: 13 pages, 3 figures

Late Mesozoic mafic dykes, high-Mg adakitic enclaves and the low-Mg adakitic host from the Fangshan pluton provide important insights into the process of crust-mantle interaction. The mafic dykes (134 ± 2 Ma) have a wide range of total alkali (Na 2 O + K 2 O: 3.41–7.11 wt.%), MgO (2.6–6.5 wt.%), Ni (60.1–541.7 ppm), and Cr (138.2–749.5 ppm) contents and high Mg # values (57.6–72.0). They are enriched in LREEs and LILEs (Rb, Ba, K) and depleted in HREEs and HFSEs (Nb, Ta, Zr, Hf), suggesting a garnet-bearing enriched mantle source. The host granodiorites (136 ± 2 Ma) have low-Mg adakitic geochemical compositions. They belong to the of high-K calc-alkaline series with low MgO contents (1.4–3.0 wt.%) and Mg # values (41.9–48.1). They exhibit extremely high Sr and low Y and Yb contents, and are strongly enriched in LREEs resulting in high Sr/Y and (La/Yb) N ratios. The low-Mg adakitic granodoirites were probably generated by partial melting of thickened eclogitic lower continental crust (LCC). The enclaves (136 ± 2 Ma) with a strong affinity to the mafic dyke show high-Mg adakitic geochemical characteristics. They are alkaline series with relatively low SiO 2 (52.2–59.6 wt.%) and high MgO (Mg # = 44.7–57.2) contents. They contain high Sr, Ni and Cr, low Y and Yb, and have very high Sr/Y and (La/Yb) N ratios, with depletion in HFSEs (Nb, Ta, Zr, Hf, Ti) but without Eu and Sr negative anomalies. Numerical simulation indicates that the high-Mg adakitic enclaves were likely produced by mixing of low-Mg adakitic melt with mantle- derived magma. We propose that the underplating of the mantle-derived magma might have triggered partial melting of the thickened LCC and resulted in the mixing between them in the Early Cretaceous.

Solid-phase extraction technique with the GC/MS method was adopted to analyze the chemical composition in an asphalt aqueous solution. The results showed that the mainly organic components were phthalates, phenols, polycyclic aromatic hydrocarbons, anilines, heterocyclic nitrogen, sulfur compounds, and surfactants. The oil source and the processing technology determined the kinds and quantities of the organic components. Moreover, organic components changed with aging degree of the asphalt.

As an asphalt modifier, diatomite could improve the road performance of asphalt. The adsorption property of diatomite was varied with different compositions of asphalt. The result suggested that diatomite with a developed mesoporous structure could effectively adsorb the lower molecular group and lower polar aromatic molecules, whereas it could not adsorb the asphaltene and resins. In addition, the adsorption amount was related to the curing time. The anchorage was formed after certain molecules in asphalt were adsorbed by diatomite and improved the property of asphalt mastic.

This paper evaluated pulping performance of 3-year-old field-grown transgenic poplar (Populus tremula × Populus alba). The transgenic poplar with anti-sense CCoAOMT had an about 13% decreased lignin content, in which a slight increment was found in S/G ratio. Chemical analysis showed that the transgenic poplar had significantly less benezene-ethanol extractive than that of control wood, but no significant differences were found in contents of ash, cold water extractive, hot water extractive, 1% NaOH extractive, holocellulose, pentosans and cellulose. Fiber assay demonstrated that down-regulation of CCoAOMT expression improved the fiber quality in transgenic poplar. Kraft pulping showed that lower lignin in transgenic poplar led to remarkable improved pulp quality and increased pulp yield.

The dynamic transesterification reaction of peanut oil in supercritical methanol media was investigated. The reaction temperature and pressure were in the range of 250°C–310°C and 10.0 MPa–16.0 Mpa, respectively. The molar ratio of peanut oil to methanol was 1:30. It was found that the yield of methyl esters was higher than 90% under the supercritical methanol. The apparent reaction order and activation energy of transesterification was 1.5 and 7.472 kJ/mol, respectively. In this method, the reaction time was shorter and the processing was simpler than that of the common acid catalysis transesterification.

The starch and cyclodextrin were selected as the precursors and the mixture of surfactant and tetraethyl orthosilicate (TEOS) as template to prepare mesoporous carbon. The result showed that a bimodal pore size distribution in mesoporous carbon derived from starch appeared; one was around 3.4 nm and the other ranged from 3.8 to 16.2 nm. However, there existed a concentrated pore size distribution from 3.2 to 4.2 nm in mesoporous carbon derived from cyclodextrin. The different molecular structure of starch and cyclodextrin and their polymerization process in the presence of sulfur acid were responsible for the resulted mesoporous carbon structure; the starch could polymerize by head to head or side by side, but the cycleodextrin was only polymerized by head to head.

Many reactions were involved in the diesel hydrorefining processes in the supercritical water-syngas system, as the mechanism of diesel hydrogenation using supercritical water-syngas was investigated by using isotopic D2. The 2H-NMR results of hydrogenated products revealed that the supercritical water-syngas could be used as an alternative hydrogen source for diesel hydrotreating because much higher deuterium content appeared in the products. The results also indicated that the hydrogen derived from supercritical water-syngas could exchange the sulfur, so hydrogen was added to the diesel molecule.

After KOH activation, the pyrolysis residues of sewage sludge could be converted to a porous carbon with a pore size situated mainly in the 0.6–1.5 nm range. The adsorption rate and capacity of the porous carbon towards Methylene Blue could be improved by the use of acoustic and magnetic fields. The best adsorption behaviour was displayed when the acoustic field frequency was 50 Hz and the magnetic field strength was 485 mT.

Regeneration of used lubricating oils by supercritical fluid extraction were investigated. The broken-down additives and impurities were removed by the high selectivity of supercritical fluid, and high-quality lube oil was obtained. Corrosion and waste-disposal problems produced by older acid-clay process have been lessened.

s Cinnamate 4-hydroxylase (C4H) plays key roles in the phenylpropanoid and lignin biosynthesis pathway. A putative C4H promoter fragment was isolated from genomic DNA of Populus tomentosa by PCR. PC4H-GUS construct was made and introduced to tobacco plants via Agrobacterium-mediated transformation. Fluorometric and histochemical GUS analysis showed that the expression of a C4H-GUS fusion product was temporally and spatially specific. It was mainly expressed in the lignified tissues and its activity gradually increased from the first to nine internodes in stems of tobacco, preceding the lignin deposition. GUS staining revealed that C4H-GUS expression was also inductive by wounding. C4H promoter fused to antisense CCoAOMT cDNA was used for manipulating lignin biosynthesis in transgenic tobacco. Experiments using transgenic plants demonstrated that the expression of the fusion gene could effectively reduce lignin content in plants without any pronounced effect on plant growth and the carbon allocation to carbohydrate pool. These results suggest that the C4H promoter from P. tomentosa could be applied in genetically improving wood quality.

The antisense Caffeoyl CoA O-methyltransferase (CCoAOMT) cDNA was transformed into Chinese white poplar (Populus tomentosa) mediated by Agrobacterium tumefaciens. Many factors affecting the transformation efficiency were studied and a stable transformation system was established. PCR-Southern blot analysis indicated that antisense CCoAOMT cDNA had been integrated into the genome of the transgenic poplars. RT-PCR and Western blot analyses demonstrated that the endogenous CCoAOMT gene was suppressed at both transcriptional and translational levels. Klason lignin content assay exhibited the lignin reduction to different degrees in transgenic poplars. The stems of partial transgenic poplars with the remarkable lignin reduction turned red, and the color distribution was stripped or spotted. Taken together, these results suggested that CCoAOMT gene would be a potential useful gene in altering lignin biosynthesis by biotechnology for improving wood properties.

RNA interference (RNAi) is a loss of function approach by which double stranded RNA (dsRNA) initiates degradation of homologous mRNAs in a sequence specific manner. The dsRNA molecules can be produced in vitro or in vivo , and can be introduced to cells in a number of ways. Here we report a more efficient method for the cloning of inverted repeat DNA fragments into expression vectors that can be transcribed into effective dsRNA molecules in vivo or in vitro . This method, named Symmetrical Directional Cloning (SDC), takes the advantage of compatible non palindromic restriction enezyme sites, which allow one to directionally clone a single PCR product in both the sense and antisense orientations together into a vector. SDC allows for the directional cloning of inverted repeats using a single PCR product; it requires only one cut site on each side of the loop. Hence this method is more cost effective and less time consuming. At least 21 commercially available restriction endonucleases can be used as cloning sites for the SDC method. The efficacy of dsRNA expression vectors prepared by SDC has been demonstrated by targeting a negative regulator of the signaling pathway mediating the response of cells to phytohormone, gibberellins (GA), in the aleurone cells.

Caffeoyl-Coenzyme A 3-O-Methyltransferase (CCoAOMT) is a key enzyme in lignin biosynthesis pathway. Three riceCCoAOMT genes were identified and designated asOsCOA1, OsCOA20 andOsCOA26. OsCOA1 contains four exons and three introns, while the other two have three exons and two introns. The deduced amino acid sequences of these rice genes share a high identity (75.43%) with other plant CCoAOMT proteins and contain the CCoAOMT specific motifs. Phylogenetic analysis indicates that OsCOA1 has the closest evolutionary relationship to maize CCoAOMT. In contrast, OsCOA20 and OsCOA26 belong to another clade. Northern blot analyses andin situ hybridization studies indicate that the three riceCCoAOMT genes are highly expressed in developing sclerenchyma cells and vessel bundles of young leaves, suggesting that they are probably involved in constitutive lignification.

The antisense4CL (4-coumarate: CoA ligase) gene was transformed into triploid Chinese white poplar (Populus tomentosa) mediated byAgrobacterium tumefaciens. PCR and Southern blot analysis indicated that antisense4CL gene had been integrated into the genome of the transgenic Chinese white poplars. The antisense gene had also been expressed, which was indicated by RT-PCR and Western analysis. Klason lignin content assay showed that repression of4CL expression could result in remarkable reduction of lignin content in transgenic poplars, with most reduction of 41.73% compared with that of wild type in this paper. But there is no significant difference in holocellulose content between transgenic and wild poplars. We considered that 4CL might not be the metabolism control point between lignin and carbohydrate biosynthesis. The stems of transgenic poplars displayed red-brown color with different levels after the bark was peeled, while those of untransformed plants were white. No visible differences in growth and development were observed between transgenic and wild plants. Wiesner reaction analysis of the transgenic plant stems with reduced lignin content exhibited red color, while that of untransformed plant was typically purple-red.

cDNA encoding 4-coumarate: CoA ligase (4CL) was isolated from the secondary developing xylem of Chinese white aspen (Populus tomentosa) by RT-PCR for the first time, which was 1619 bp in length. The coding sequence and putative amino acid sequence showed 97. 53 % and 97.00% identity to that of Pt4CLl in quaking aspen (P. tremuloids), respectively. Molecular analysis indicated that 4CL was encoded by multiple genes in P. tomentosa, its mRNA was highly accumulated in xylem and the expression of 4CL revealed a biphasic pattern in one growing season, almost in phase with the expression of other related enzymes in lignin biosynthesis. Transgenic research showed that expression of antisense 4CL cDNA led to the decreasing of lignin content in transgenic tobaccos, among which the average reduction was 10. 3 % and the highest could be up to 18.9%. These data suggested that 4CL gene was a potential gene used in altering lignin biosynthesis by biotechnology for producing new materials of papermaking.

The seed-specific promoter and transit peptide were amplified and fused to the three genesphbA, phbB andphbC encoding PHB synthetic enzymes, respectively. Seed-specific expression vectors pSCB containingphbC andphbB, and pSCAB containingphbC, phbB andphbA, were constructed by introducing the genes with promoter and peptide into the binary vector pBI101. TransgenicBrassica napus H165 were obtained byAgrobacterium-mediated transformation with these vectors. They were confirmed by PCR, Southern and RT-PCR analyses.