RF modeling of the ITER-relevant lower hybrid antenna

In the frame of the EFDA task HCD-08-03-01, a 5 GHz Lower Hybrid system which should be able to deliver 20 MW CW on ITER and sustain the expected high heat fluxes has been reviewed. The design and overall dimensions of the key RF elements of the launcher and its subsystem has been updated from the 2001 design in collaboration with ITER organization. Modeling of the LH wave propagation and absorption into the plasma shows that the optimal parallel index must be chosen between 1.9 and 2.0 for the ITER steady-state scenario. The present study has been made with n_|| = 2.0 but can be adapted for n_|| = 1.9. Individual components have been studied separately giving confidence on the global RF design of the whole antenna.     

Microfluidic tools for cell biological research

Microfluidic technology is creating powerful tools for cell biologists to control the complete cellular microenvironment, leading to new questions and new discoveries. We review here the basic concepts and methodologies in designing microfluidic devices, and their diverse cell biological applications.     

Tandem Catalysis: Access to Ketones from Aldehydes and Arylboronic Acids via Rhodium‐Catalyzed Addition/Oxidation

Direct cross‐coupling reactions of aromatic aldehydes with arylboronic acids afforded ketones in high yields and under mild conditions in the presence of a rhodium catalyst, acetone and a base. This new reaction, involving a formal aldehyde C H bond activation, is believed to proceed via a tandem process involving addition of the organometallic species to the aldehyde followed by oxidation by β‐hydride transfer.     

Realization of vertical silicon nanowire networks with an ultra high density using a top-down approach

In this paper, we demonstrate the top-down fabrication of vertical silicon nanowires networks with an ultra high density (4 x 10(10) cm(-2)), a yield of 100%, and a precise control of both diameter and location. Firstly, dense and well-defined networks of nanopillars have been patterned by e-beam lithography using a negative tone e-beam resist Hydrogen SylsesQuioxane (HSQ). A very high contrast has been obtained using a high acceleration voltage (100 kV), very small beam size at a current of 100 pA and a concentrated developer, 25% Tetramethylammonium Hydroxide. The patterns were transferred by reactive ion etching. Using chlorine based plasma chemistry and low pressure, etching anisotropy was guaranteed while avoiding the so-called 'grass effect'. This approach enabled the production of vertical silicon nanowires networks with a 20 nm diameter and a pitch of 30 nm. Lastly, the self-limited oxidation phenomenon in 1D structure has been used to perfectly control the shrinking of NWs and to obtain a Si surface free of defects induced by reactive ion etching. The silicon nanowires networks have been tapered by wet oxidation (850 degrees C) down to a diameter of 10 nm with a high aspect ratio 11.     

Understanding and assessing the motivations of volunteers: a functional approach

The authors applied functionalist theory to the question of the motivations underlying volunteerism, hypothesized 6 functions potentially served by volunteerism, and designed an instrument to assess these functions (Volunteer Functions Inventory; VFI). Exploratory and confirmatory factor analyses on diverse samples yielded factor solutions consistent with functionalist theorizing; each VFI motivation, loaded on a single factor, possessed substantial internal consistency and temporal stability and correlated only modestly with other VFI motivations (Studies 1, 2, and 3). Evidence for predictive validity is provided by a laboratory study in which VFI motivations predicted the persuasive appeal of messages better when message and motivation were matched than mismatched (Study 4), and by field studies in which the extent to which volunteers' experiences matched their motivations predicted satisfaction (Study 5) and future intentions (Study 6). Theoretical and practical implications are discussed.     

Active immunization with tumor cells transduced by a novel AAV plasmid-based gene delivery system

Ex vivo genetically engineered cytokine-secreting tumor cell vaccines have been shown to prevent metastatic disease in animal models of lung and breast cancer. Because of the inefficiency of existing modes of gene delivery in transducing primary human tumor cells, it has been difficult to clinically apply this strategy. In this study, liposome-mediated delivery of an adeno-associated virus (AAV)-based plasmid containing the sequence for murine gamma-interferon (gamma-IFN) (pMP6A-mIFN-gamma) was used to generate cytokine-secreting murine tumor cell vaccines. High levels of gamma-IFN and elevated class I major histocompatibility complex expression after transfer of pMP6A-mIFN-gamma into the murine lung cancer cell line, D122, was demonstrated. The efficiency of gene transfer was determined by two different methods and was estimated to be 10-15%. Irradiated gamma-IFN D122 cells generated by this novel gene delivery system (D122/pMP6A-mIFN-gamma) and also by standard retroviral methods (DIF2) were administered as weekly vaccinations by intraperitoneal injection to animals bearing 7-day-old intrafootpad D122 tumors. Hindlimb amputation was performed when footpad diameters reached 7 mm, and lungs were harvested 28 days later. Animals vaccinated with gamma-IFN-secreting D122 cells produced by AAV-based plasmids delivery demonstrated a significant delay in footpad tumor growth when compared with controls and DIF2 cells. Fifty-seven percent of animals vaccinated with D122/pMP6A-mIFN-gamma were free of pulmonary metastases 28 days after amputation, significantly improved from the 0, 7, and 15% observed in animals vaccinated with irradiated parental D122 cells, irradiated D122 cells lipofected with an empty-cassette vector (pMP6A), or DIF2 cells, respectively. These results and the ability to transfer genes with this delivery system to a broad range of tumor types support its use in the generation of cytokine-secreting tumor cell vaccinations for use in clinical trials.     

Climate sensitivity of gaseous elemental mercury dry deposition to plants: impacts of temperature, light intensity, and plant species

Foliar accumulations of gaseous elemental mercury (GEM) were measured in three plant species between nominal temperatures of 10 and 30 °C and nominal irradiances of 0, 80, and 170 W m(-2) (300 nm-700 nm) in a 19 m(3) controlled environment chamber. The plants exposed were as follows: White Ash (Fraxinus americana; WA); White Spruce (Picea glauca; WS); and Kentucky Bluegrass (Poa partensis; KYBG). Foliar enrichments in the mercury stable isotope ((198)Hg) were used to measure mercury accumulation. Exposures lasted for 1 day after which the leaves were digested in hot acid and the extracted mercury was analyzed with ICPMS. Resistances to accumulative uptake by leaves were observed to be dependent on both light and temperature, reaching minima at optimal growing conditions (20 °C; 170 W m(-2) irradiance between 300-700 nm). Resistances typically increased at lower (10 °C) and higher (30 °C) temperatures and decreased with higher intensities of irradiance. Published models were modified and used to interpret the trends in stomatal and leaf interior resistances to GEM observed in WA. The model captured the experimental trends well and revealed that stomatal and internal resistances were both important across much of the temperature range. At high temperatures, however, stomatal resistance dominated due to increased water vapor pressure deficits. The resistances measured in this study were used to model foliar accumulations of GEM at a northern US deciduous forest using atmospheric mercury and climate measurements made over the 2003 growing season. The results were compared to modeled accumulations for GEM, RGM, and PHg using published deposition velocities. Predictions of foliar GEM accumulation were observed to be a factor of 5-10 lower when the temperature and irradiance dependent resistances determined in this study were used in place of previously published data. GEM uptake by leaves over the growing season was shown to be an important deposition pathway (2.3-3.7 μg m(-2) of one-sided leaf area; OSLA) when compared to total mercury wet deposition (1.2 μg m(-2) OSLA) and estimates of reactive mercury dry deposition (0.1-6 μg m(-2) OSLA). Resistance-Temperature-Irradiance relationships are provided for use in models.     

Structural Characterization,Technological Functionality,and Physiological Aspects of Fungal β-D-glucans: A Review

β-D-glucans are a (1→3)-linked glucose polymer with (1→6)-linked side chains and a major component of fungal cell walls. They exhibit structural integrity to the fungal cell wall. In addition, β-glucans are widely used as food adjuvant in food and pharmaceutical industries because of their physico-chemical properties. Several studies have focused on different isolation processes of (1→3) (1→6)-β-glucan that could affect the physico-chemical and functional properties of β-glucan such as chemical composition, solubility, viscosity, hydration properties, and oil binding capacity. Immunological activity is one of the most important properties of β-glucans. Thus, they are effective in inhibiting growth of cancer cells and metastasis and preventing bacterial infection. In humans, β-glucans reduce blood cholesterol, improve glucose absorption by body cells, and so help wound healing. This review described the prebiotic potentiality of fungal β-D-glucans with the objective to detail the methodologies applied for their extraction, their structure and techno-functional properties, and finally their biological effects.