Color breakup suppression based on global dimming for field sequential color displays using edge information in images.

Considering the high complexity of local dimming backlight that is necessary to effectively suppress color breakups for field sequential color liquid crystal displays (FSC-LCDs), a global dimming-based solution is proposed. This solution involves considering that the color breakups mainly occur at object edges of an image. By introducing an algorithm to present the edge information in a single field, evaluating color breakup performances, and experimentally verifying based on a 240-Hz LCD, lighter color breakups are revealed compared with mainstream local dimming-based solutions. Therefore, the proposed solution can achieve FSC-LCDs with better performance and practicality for advanced display applications.

Polychromatic SSVEP stimuli with subtle flickering adapted to brain-display interactions.

OBJECTIVE: Interactive displays armed with natural user interfaces (NUIs) will likely lead the next breakthrough in consumer electronics, and brain-computer interfaces (BCIs) are often regarded as the ultimate NUI-enabling machines to respond to human emotions and mental states. Steady-state visual evoked potentials (SSVEPs) are a commonly used BCI modality due to the ease of detection and high information transfer rates. However, the presence of flickering stimuli may cause user discomfort and can even induce migraines and seizures. With the aim of designing visual stimuli that can be embedded into video images, this study developed a novel approach to induce detectable SSVEPs using a composition of red/green/blue flickering lights. APPROACH: Based on the opponent theory of colour vision, this study used 32 Hz/40 Hz rectangular red-green or red-blue LED light pulses with a 50% duty cycle, balanced/equal luminance and 0°/180° phase shifts as the stimulating light sources and tested their efficacy in producing SSVEP responses with high signal-to-noise ratios (SNRs) while reducing the perceived flickering sensation. MAIN RESULTS: The empirical results from ten healthy subjects showed that dual-colour lights flickering at 32 Hz/40 Hz with a 50% duty cycle and 180° phase shift achieved a greater than 90% detection accuracy with little or no flickering sensation. SIGNIFICANCE: As a first step in developing an embedded SSVEP stimulus in commercial displays, this study provides a foundation for developing a combination of three primary colour flickering backlights with adjustable luminance proportions to create a subtle flickering polychromatic light that can elicit SSVEPs at the basic flickering frequency.

Habituation of steady-state visual evoked potentials in response to high-frequency polychromatic foveal visual stimulation.

In an attempt to develop safe and robust methods for monitoring migraineurs' brain states, we explores the feasibility of using white, red, green and blue LED lights flickering around their critical flicker fusion (CFF) frequencies as foveal visual stimuli for inducing steady-state visual evoked potentials (SSVEP) and causing discernible habituation trends. After comparing the habituation indices, the multi-scale entropies and the time dependent intrinsic correlations of their SSVEP signals, we reached a tentative conclusion that sharp red and white light pulses flickering barely above their CFF frequencies can replace commonly used 13Hz stimuli to effectively cause SSVEP habituation among normal subjects. Empirical results showed that consecutive short bursts of light can produce more consistent responses than a single prolonged stimulation. Since these high frequency stimuli do not run the risk of triggering migraine or seizure attacks, further tests of these stimuli on migraine patients are warranted in order to verify their effectiveness.

Application of field emission as backlight unit for liquid crystal displays.

The paper first analyzes the effect of backlight unit for liquid crystal displays on the respect of image quality and power consumption. A spatially and temporally addressable backlight is required in the future liquid crystal displays which have lower power consumption and higher image quality. Compared to the currently used light emitting diode backlight, the simulation results indicate that a rectangular-shaped backlight has better performances on the respect of reducing power consumption and improving image quality. A backlight cell based on the field emission is manufactured and studied. It uses a mixture of multi-wall carbon nanotubes and tetrapod-like zinc oxide nanostructures as the cathode and applies spin-coating process for fabrication. The experiment shows that such field emission backlight unit has a low turn-on field which enables a high backlight luminance at acceptable driving voltage. Besides, this mixture cathode helps to improve the uniformity of field emission in both spatial and temporal domain which is important for the application of backlight unit.

SNR analysis of high-frequency steady-state visual evoked potentials from the foveal and extrafoveal regions of human retina.

With brain-computer interface (BCI) applications in mind, we analyzed the amplitudes and the signal-to-noise ratios (SNR) of steady-state visual evoked potentials (SSVEP) induced in the foveal and extra-foveal regions of human retina. Eight subjects (age 20-55) have been exposed to 2° circular and 16°-18° annular visual stimulation produced by white LED lights flickering between 5Hz and 65Hz in 5Hz increments. Their EEG signals were recorded using a 64-channel NeuroScan system and analyzed using non-parametric spectral and canonical convolution techniques. Subjects' perception of flickering and their levels of comfort towards the visual stimulation were also noted. Almost all subjects showed distinctively higher SNR in their foveal SSVEP responses between 25Hz and 45Hz. They also noticed less flickering and felt more comfortable with the visual stimulation between 30Hz and 45Hz. These empirical evidences suggest that lights flashing above the critical flicker fusion rates (CFF) of human vision may be used as effective and comfortable stimuli in SSVEP BCI applications.

Expression of B7-H4 in prostate cancer and its clinical significance / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To investigate the expression of B7-H4 in prostate cancer tissue and the relationship between the expression and the clinicopathological features.</p><p><b>METHODS</b>Immunohistochemical staining was used to detect the expression of B7-H4 in prostate cancer tissue. And the relationship between the expressions and pathology was evaluated.</p><p><b>RESULTS</b>The B7-H4 was diffusely expressed in cytoplasm and/or membrane of the prostate cancer tissue; the expression was much higher than that in normal prostate tissue (P<0.05). The expression of B7-H4 in the prostate cancer tissue was higher in patients with higher tumor grade.</p><p><b>CONCLUSION</b>B7-H4 may be used as an new indicator for the diagnosis and prognosis of prostate cancer and a novel target for immunotherapy.</p>

Expression and identification of recombinant mouse gene B7-H4 / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To construct a eukaryotic expression vector encoding the gene of extracellular region of mouse B7-H4, to express it in yeast cell line and to determine its biological activity.</p><p><b>METHODS</b>The extracellular region of the mouse B7-H4 gene was amplified with Xho I and EcoR I by PCR from a mouse B7-H4 chimeric plasmid. Digested with Xho I and EcoR I, the mB7-H4 gene was inserted into the yeast expression plasmid Ppic9. The DNA sequence was confirmed by double digestion and the Ppic9-mB7-H4 plasmid was transfected into the yeast cells. The expression of mB7-H4 was confirmed by PCR, Western Blot and ELISA analysis, and its biological function was determined.</p><p><b>RESULT</b>Ppic9-mB7-H4 transfectants expressed mB7-H4 in yeast cells, and mB7-H4 effectively inhibited the proliferation of T lymphocytes with a fractional inhibition rate of 28.3 % and inhibited IL-2, IL-4, IL-10 and IFN-gamma production with fractional inhibition rates of 68.8%, 78.8%, 67.6% and 77.7%, respectively.</p><p><b>CONCLUSION</b>The eukaryotic expression plasmid mouse B7-H4 has been successfully constructed and the expressed products of B7-H4 possess biological activity.</p>