Sugar‐feeding status alters biting midge photoattraction

The biting midge Culicoides sonorensis Wirth and Jones (Diptera: Ceratopogonidae) transmits pathogens to both livestock and wildlife. Biting midge surveillance relies heavily on light traps for collection; however, little is known about the light spectra preferences of C. sonorensis midges. A light assay arena was constructed and light‐emitting diodes (LEDs) of various light spectra were used as light sources to evaluate midge photoattraction. A comparison of responses to light spectra indicated the highest proportions of C. sonorensis were attracted to ultraviolet (UV) light and that midges differentiated 10‐nm differences in wavelength. Stronger intensities of UV light resulted in greater attraction. Midges exhibited both sugar‐seeking and escape behaviours under different conditions of sugar supplementation before and during the experiment. These behaviours occurred with lights of 355 nm and 365 nm in wavelength. Based on the results of this study, the attraction of C. sonorensis to light traps can be improved through the use of bright LEDs at 355 nm or 365 nm.     

High-density algal photobioreactors using light-emitting diodes

Lack of high-density algal photobioreactors (PBR) has been a limitation in exploiting the biotechnological potential of algae. Recent developments of highly efficient light-emitting diodes (LED using gallium aluminum arsenide chips) have made the development of a small LED-based PBR possible. We have calculated theoretical values of gas mass transfer requirements and light-intensity requirement to support high-density algal cultures for the 680 nm monochromatic red light from LED as a light source. A prototype PBR has been designed based on these calculations. A cell concentration of more than 2 x 10(9) cells/mL (more than 6.6% v%sol;v), cell doubling times as low as 12 h, and an oxygen production rate as high as 10 mmol oxygen/L culture/h were achieved using on-line ultrafiltration to periodically provide fresh medium. (c) 1994 John Wiley & Sons, Inc.     

Nanomoulding of Functional Materials,a Versatile Complementary Pattern Replication Method to Nanoimprinting

We describe a nanomoulding technique which allows low-cost nanoscale patterning of functional materials, materials stacks and full devices. Nanomoulding combined with layer transfer enables the replication of arbitrary surface patterns from a master structure onto the functional material. Nanomoulding can be performed on any nanoimprinting setup and can be applied to a wide range of materials and deposition processes. In particular we demonstrate the fabrication of patterned transparent zinc oxide electrodes for light trapping applications in solar cells.     

UVC fluencies for preventative treatment of Pseudomonas aeruginosa contaminated polymer tubes

Exposing Pseudomonas aeruginosa biofilm grown on the inner surface of Teflon and silicone tubes to UVC light (265 nm) from light emitting diodes (LED) has previously been shown to substantially reduce biofilm growth. Smaller UVC fluencies were required to disinfect Teflon tubes compared to silicone tubes. Light propagation enhancement in tubes can be obtained if the refractive index of the intra-luminal saline solution is higher than that of the polymer. This condition is achieved by using Teflon tubes with a low refractive index (1.34) instead of the polymers with a high refractive index (1.40–1.50) normally used for tubing in catheter production. Determining whether or not UVC light exposure can disinfect and maintain the intra-luminal number of colony forming units (CFUs) at an exceedingly low level and thus avoid the growth and establishment of biofilm is of interest. The use of UVC diodes is demonstrated to be a preventative disinfection treatment on tubes made of Teflon, which enhances the UVC light propagation, and on tubes made of a softer material, ethylene vinyl acetate (EVA), which is suitable for catheters but much less suitable for UVC light propagation. Simulating an aseptic breach (～10³–10⁴ CFU ml^?1), the UVC disinfection set-up was demonstrated using tubes contaminated with planktonic P. aeruginosa. After the tubes (10–20 cm) were inoculated with the bacterial solution for 3 h, they were emptied and filled with saline solutions (0.9–20%). Next UVC fluencies (0–21 mJ cm^?2) were applied to the tubes 3 h after inoculation. Colony counts were carried out on liquid samples drawn from the tubes the first day after UVC treatment and liquid and surface samples were collected and analyzed 3–4 days later. A fluence of approximately 1.0 mJ cm^?2 was noted as being sufficient for no growth for a period of 3–4 days for the Teflon tubes. Determining the fluence threshold for the EVA tubes was not possible. Almost all of the UVC-treated EVA tubes were disinfected simply by filling the tubes with a saline solution. Direct UVC treatment of the contaminated EVA tubes revealed, however, that a fluence of 21 mJ cm^?2 killed the bacteria present in the tubes and kept them disinfected for a period of 3–4 days.     

Responses of epidermal cell turgor pressure and photosynthetic activity of leaves of the atmospheric epiphyte Tillandsia usneoides (Bromeliaceae) after exposure to high humidity

It has been well-established that many epiphytic bromeliads of the atmospheric-type morphology, i.e., with leaf surfaces completely covered by large, overlapping, multicellular trichomes, are capable of absorbing water vapor from the atmosphere when air humidity increases. It is much less clear, however, whether this absorption of water vapor can hydrate the living cells of the leaves and, as a consequence, enhance physiological processes in such cells. The goal of this research was to determine if the absorption of atmospheric water vapor by the atmospheric epiphyte Tillandsia usneoides results in an increase in turgor pressure in leaf epidermal cells that subtend the large trichomes, and, by using chlorophyll fluorescence techniques, to determine if the absorption of atmospheric water vapor by leaves of this epiphyte results in increased photosynthetic activity. Results of measurements on living cells of attached leaves of this epiphytic bromeliad, using a pressure probe and of whole-shoot fluorescence imaging analyses clearly illustrated that the turgor pressure of leaf epidermal cells did not increase, and the photosynthetic activity of leaves did not increase, following exposure of the leaves to high humidity air. These results experimentally demonstrate, for the first time, that the absorption of water vapor following increases in atmospheric humidity in atmospheric epiphytic bromeliads is mostly likely a physical phenomenon resulting from hydration of non-living leaf structures, e.g., trichomes, and has no physiological significance for the plant's living tissues.     

Retrospective assessment of a single fiducial marker tracking regimen with robotic stereotactic body radiation therapy for liver tumours

AimTo investigate tumour motion tracking uncertainties in the CyberKnife Synchrony system with single fiducial marker in liver tumours.BackgroundIn the fiducial-based CyberKnife real-time tumour motion tracking system, multiple fiducial markers are generally used to enable translation and rotation corrections during tracking. However, sometimes a single fiducial marker is employed when rotation corrections are not estimated during treatment.Materials and methodsData were analysed for 32 patients with liver tumours where one fiducial marker was implanted. Four-dimensional computed tomography (CT) scans were performed to determine the internal target volume (ITV). Before the first treatment fraction, the CT scans were repeated and the marker migration was determined. Log files generated by the Synchrony system were obtained after each treatment and the correlation model errors were calculated. Intra-fractional spine rotations were examined on the spine alignment images before and after each treatment.ResultsThe mean (standard deviation) ITV margin was 4.1 (2.3) mm, which correlated weakly with the distance between the fiducial marker and the tumour. The mean migration distance of the marker was 1.5 (0.7) mm. The overall mean correlation model error was 1.03 (0.37) mm in the radial direction. The overall mean spine rotations were 0.27° (0.31), 0.25° (0.22), and 0.23° (0.26) for roll, pitch, and yaw, respectively. The treatment time was moderately associated with the correlation model errors and weakly related to spine rotation in the roll and yaw planes.ConclusionsMore caution and an additional safety margins are required when tracking a single fiducial marker.     

Artifact‐free objective‐type multicolor total internal reflection fluorescence microscopy with light‐emitting diode light sources—Part I

Total internal reflection fluorescence excitation (TIRF) microscopy allows the selective observation of fluorescent molecules in immediate proximity to an interface between different refractive indices. Objective‐type or prism‐less TIRF excitation is typically achieved with laser light sources. We here propose a simple, yet optically advantageous light‐emitting diode (LED)‐based implementation of objective‐type TIRF (LED‐TIRF). The proposed LED‐TIRF condenser is affordable and easy to set up at any epifluorescence microscope to perform multicolor TIRF and/or combined TIRF‐epifluorescence imaging with even illumination of the entire field of view. Electrical control of LED light sources replaces mechanical shutters or optical modulators. LED‐TIRF microscopy eliminates safety burdens that are associated with laser sources, offers favorable instrument lifetime and stability without active cooling. The non‐coherent light source and the type of projection eliminate interference fringing and local scattering artifacts that are associated with conventional laser‐TIRF. Unlike azimuthal spinning laser‐TIRF, LED‐TIRF does not require synchronization between beam rotation and the camera and can be monitored with either global or rolling shutter cameras. Typical implementations, such as live cell multicolor imaging in TIRF and epifluorescence of imaging of short‐lived, localized translocation events of a Ca²⁺‐sensitive protein kinase C α fusion protein are demonstrated.     

Identification of assembly precursors to photosystems emitting fluorescence at 683 nm and 687 nm by cryogenic fluorescence microspectroscopy

Photosystem I (PSI) and photosystem II (PSII) play key roles in photoinduced electron-transfer reaction in oxygenic photosynthesis. Assemblies of these PSs can be initiated by illumination of the etiolated seedlings (greening). The study aimed to identify specific fluorescence spectral components relevant to PSI and PSII assembly intermediates emerging in greening seedlings of Zea mays, a typical C4 plant. The different PSII contents between the bundle sheath (BS) and mesophyll (M) cells were utilized to spectrally isolate the precursors to PSI and PSII. The greening Zea mays leaf thin sections were observed with the cryogenic microscope combined with a spectrometer. With the aid of the singular-value decomposition analysis, we could identify four independent fluorescent species, SAS677, SAS685, SAS683, and SAS687, named after their fluorescence peak wavelengths. SAS677 and SAS685 are the dominant components after the 30-minute greening, and the distributions of these components showed no clear differences between M and BS cells, indicating immature cell differentiation in this developing stage. On the other hand, the 1-hour greening resulted in reduced distributions of SAS683 in BS cells leading us to assign this species to PSII precursors. The 2-hour greening induced the enrichment of SAS687 in BS cells suggesting its PSI relevance. Similarity in the peak wavelengths of SAS683 and the reported reaction center of PSII implied their connection. SAS687 showed an intense sub-band at around 740 nm, which can be assigned to the emission from the red chlorophylls specific to the mature PSI.     

Effects of Various Light-Emitting Diode (LEd) Wavelengths on the Growth of Scenedesmus Obliquus Fachb-12 and Accumulation of Astaxanthin

Given the central role of light in the algal photosynthesis, respiration, cell division, growth and the accumulation of value products, the effects of light-emitting diodes (LEDs) light wavelengths (blue, white, red and green) were studied in Scenedesmus obliquus. Biomass, residual nutrient amount, soluble protein, astaxanthin and reactive oxygen species, superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD) activity were analyzed to determine the effects of different monochromatic light wavelengths via biochemical methods. The results showed that blue light wavelength is the optimal light wavelength for phosphorus removal efficiency and the accumulation of biomass and astaxanthin in S. obliquus. Meanwhile, high reactive oxygen species content under the blue light might induce the accumulation of astaxanthin. The high activity of SOD, CAT and POD might participate in clearing the reactive oxygen species to facilitate the growth of microalgae. Furthermore, we found mixed blue/green lights treatment is the most appropriate mixture for the nitrogen removal. Under the blue light treatment, high light intensity and 18L:6D light cycle is the best condition for biomass and astaxanthin accumulation. Optimal nitrogen/phosphorus removal efficiency was observed under a 24L:0D light cycle. These results might provide a foundational data for the optimizing the productivity of high-value metabolites and treatment of wastewater.     

Micropropagation of calla lily (<Emphasis Type="Italic">Zantedeschia albomaculata</Emphasis>) via <Emphasis Type="Italic">in vitro</Emphasis> shoot tip proliferation

Summary A method for the micropropagation of Zantedeschia albomaculata is presented using shoot tip proliferation onto Murashige and Skoog (MS) medium supplemented with different plant growth regulator concentrations and combinations. Of the four cytokinins tested, 6-benzyladenine (BA) and thidiazuron (TDZ) were found to be more effective. An optimal concentration of BA (8.87 μM) or TDZ (4.54 μM) developed an average of 3.8 and 3.2 shoots per explant, respectively, but increasing concentrations of cytokinins often led to lower proliferation rate and stunted growth. Addition of auxins to the MS medium supplemented with 8.87 μM BA slightly enhanced multiple shoot formation in the explants. Multiplication of six cultivars of Zantedeschia genus comprising different flower types and colors were tested and achieved using only one regeneration medium (MS+8.87 μMBA+2.46 μM IBA). Different MS medium strength, air temperature (15, 20, 25, and 30°C) and light quality [fluorescent, red + blue, red and blue light provided by a LED (light-emitting diode) system] were used (without phytohormone) with the aim of stimulating in vitro shoot and root development. Half-strength MS or MS and cultures maintained at 25°C were found to be equally suitable for shoot tip culture of Z. albomaculata. Shoot elongation as well as fresh and dry weight were significantly increased when cultures were kept under red or blue light.