Plasma current start-up by the outer ohmic heating coils in the Saskatchewan TORus Modified (STOR-M) iron core tokamak

A plasma current up to 15 kA has been driven with outer ohmic heating (OH) coils in the STOR-M iron core tokamak. Even when the inner OH coil is disconnected, the outer OH coils alone can induce the plasma current as primary windings and initial breakdown are even easier in this coil layout. This result suggests a possibility to use an iron core in a spherical tokamak to start up the plasma current without a central solenoid. The effect of the iron core saturation on the extension of the discharge pulse length has been estimated for further experiments in the STOR-M tokamak.

Experimental proof of adjustable single-knob ion beam emittance partitioning

The performance of accelerators profits from phase-space tailoring by coupling of degrees of freedom. Previously applied techniques swap the emittances among the three degrees but the set of available emittances is fixed. In contrast to these emittance exchange scenarios, the emittance transfer scenario presented here allows for arbitrarily changing the set of emittances as long as the product of the emittances is preserved. This Letter is the first experimental demonstration of transverse emittance transfer along an ion beam line. The amount of transfer is chosen by setting just one single magnetic field value. The envelope functions (beta) and slopes (alpha) of the finally uncorrelated and repartitioned beam at the exit of the transfer line do not depend on the amount of transfer.

Heavy metals distribution and contamination in surface sediments of the coastal Shandong Peninsula (Yellow Sea)

Selected heavy metals (Cr, Cu, Ni, Pb and Zn) in surface sediments from the coastal Shandong Peninsula (Yellow Sea) have been determined to evaluate the spatial distribution and potential ecological risk. Results showed that heavy metal concentrations in the sediments generally met the criteria of China Marine Sediment Quality. However, both the enrichment factor (EF) and geoaccumulation index (Igeo) values suggested the elevation of Pb concentration in the region. Based on the effect-range classification (TEL-PEL SQGs), Cr, Cu and Ni were likely to pose environment risks. Spatial distribution of ecotoxicological index (mean-PEL-quotient) suggested that most of the surface sediments have a 21% probability of being toxic. Similar results were also obtained by pollution load index (PLI). The spatial distribution pattern of heavy metal in surface sediments is a basis for undertaking appropriate action to protect marine sediment quality.

Multi-armed poly(aspartate-g-OEI) copolymers as versatile carriers of pDNA/siRNA

To search for potential non-viral nucleic acids carriers, a series of novel cationic polymers, multi-armed poly(aspartate-graft-oligoethylenimine) (MP-g-OEI) copolymers were designed and synthesized by grafting different types of oligoethylenimine (OEI) to a multi-armed poly(l-aspartic acid) backbone. The as-synthesized MP-g-OEI copolymers were characterized by Fourier transform infrared spectroscopy, nuclear magnetic resonance and gel permeation chromatography. These MP-g-OEI copolymers (MP423, MP600 and MP1800) exhibited good capacity in condensing nucleic acids (pDNA or siRNA) into nanosized particles (90-150nm) with positive surface charges. Gene transfection activity of the MP-g-OEI copolymers (especially MP1800) showed improved performance compared with PEI25k in both HeLa and CHO cell lines. The silencing efficiency of MP600/siRNA and MP1800/siRNA complexes showed a superior knockdown effect in CT26 and Huh-7 cell lines. Moreover, the MP-g-OEI copolymers exhibited much lower cytotoxicity than PEI25k. Flow cytometric analysis showed that MP-g-OEI copolymers could efficiently mediate the entry of nucleic acids into cells. These results suggest that MP-g-OEI copolymers may be potential non-viral gene carriers for the delivery of nucleic acids in future gene therapy.

Push-pull effects of three plant secondary metabolites on oviposition of the potato tuber moth, Phthorimaea operculella

The push-pull effects of three plant secondary metabolites, azadirachtin, eucalyptol, and heptanal, on the oviposition choices of potato tubers by the potato tuber moth, Phthorimaea operculella (Zeller) (Lepidoptera: Gelechiidae) were tested in the laboratory. Azadirachtin at concentrations from 1.5 to 12 mg/L had a significant repellent effect on oviposition. Eucalyptol at concentrations from 3 to 12 mg/L promoted oviposition. Heptanal promoted oviposition at low concentrations from 0.1875 to 3.0 mg/L but repelled it at higher concentrations from 12 to 24 mg/L. The combination of azadirachtin (12 mg/L) with eucalyptol (3.0 mg/L) resulted in a significant pushpull effect of 56.3% on oviposition. The average maximum push-pull effects occurred with the combinations of azadirachtin with heptanal (12 and 0.375 mg/L, respectively; 38.7% push-pull effect), heptanal with eucalyptol (12 and 6 mg/L, respectively; 31.4% push-pull effect), and heptanal (high concentration) with heptanal (low concentration) (12.0 and 0.375 mg/L, respectively; 25% push-pull effect).

Preactivation of the interferon signalling in liver is correlated with nonresponse to interferon alpha therapy in patients chronically infected with hepatitis B virus

Interferon alpha (IFN-α) therapy is widely used to treat patients with chronic hepatitis B (CHB) but the sustained response rate is low, and the molecular mechanisms for the ineffectiveness of IFN-α treatments are not known. We screened differentially expressed genes between responders (Rs) and nonresponders (NRs) in patients with CHB treated with IFN-α to explore the molecular basis for treatment failure. Expression profiling was performed on percutaneous needle liver biopsy specimens taken before therapy. Gene expression levels were compared between seven patients who did not respond to therapy (NR) and six who did respond (R). Gene ontology category and KEGG pathway were analysed for differentially expressed genes, and the selected differentially expressed genes were confirmed using real-time polymerase chain reaction. We identified 3592 genes whose expression levels differed significantly between all Rs and NRs (P < 0.05); many of these genes are IFN-stimulated genes (ISGs) and immune-related genes. The ISGs were more highly expressed, while immune-related genes were inhibited in NRs before IFN-α treatment. Two ISGs (CEB1 and USP18) that are linked in an IFN inhibitory pathway are highly expressed in NRs, and a potential antiviral gene ISG20 was inhibited in NRs, suggesting a possible rationale for treatment nonresponse. Patients who do or do not respond to IFN have different liver gene expression profiles before IFN-α treatment. Preactivation of the IFN signalling pathway leading to the increased expression of inhibitory ISGs and inhibition of immune response in the pretreatment livers was associated with treatment failure.

High density and scale-up cultivation of recombinant CHO cell line and hybridomas with porous microcarrier Cytopore

Using porous microcarrier Cytopore and a low-serum medium supplement BIGBEF-3, we have successfully cultivated recombinant CHO cell line CL-11G producing prourokinase and hybridomas producing anti-prourokinase monoclonal antibody in Celligen 1.5 or 5 L bioreactor. The cell density obtained ranged from 1 to 2 x 107 cells mL-1. The yields of prourokinase and monoclonal antibody increased with increasing cell density. As the cells could spontaneously release from and reattach to porous microcarriers, it was very easy to scale-up the cultivation. Thus the bead to bead cell transfer method has been used to scale up the cultivation of CL-11G cells to a 20 L reactor-scale for the pilot production of prourokinase, and also to scale-up the culture of hybridomas for the production of monoclonal antibody for the purification of prourokinase.