LEDs for photons, physiology and food.

Lighting based on light-emitting diodes (LEDs) not only is more energy efficient than traditional lighting, but also enables improved performance and control. The colour, intensity and distribution of light can now be controlled with unprecedented precision, enabling light to be used both as a signal for specific physiological responses in humans and plants, and as an efficient fuel for fresh food production. Here we show how a broad and improved understanding of the physiological responses to light will facilitate greater energy savings and provide health and productivity benefits that have not previously been associated with lighting.

Four-color laser white illuminant demonstrating high color-rendering quality.

Solid-state lighting is currently based on light-emitting diodes (LEDs) and phosphors. Solid-state lighting based on lasers would offer significant advantages including high potential efficiencies at high current densities. Light emitted from lasers, however, has a much narrower spectral linewidth than light emitted from LEDs or phosphors. Therefore it is a common belief that white light produced by a set of lasers of different colors would not be of high enough quality for general illumination. We tested this belief experimentally, and found the opposite to be true. This result paves the way for the use of lasers in solid-state lighting.

Design of adaptive fuzzy logic controller based on linguistic-hedge concepts and genetic algorithms.

In this paper, we propose a novel fuzzy logic controller, called linguistic hedge fuzzy logic controller, to simplify the membership function constructions and the rule developments. The design methodology of linguistic hedge fuzzy logic controller is a hybrid model based on the concepts of the linguistic hedges and the genetic algorithms. The linguistic hedge operators are used to adjust the shape of the system membership functions dynamically, and ran speed up the control result to fit the system demand. The genetic algorithms are adopted to search the optimal linguistic hedge combination in the linguistic hedge module, According to the proposed methodology, the linguistic hedge fuzzy logic controller has the following advantages: 1) it needs only the simple-shape membership functions rather than the carefully designed ones for characterizing the related variables; 2) it is sufficient to adopt a fewer number of rules for inference; 3) the rules are developed intuitionally without heavily depending on the endeavor of experts; 4) the linguistic hedge module associated with the genetic algorithm enables it to be adaptive; 5) it performs better than the conventional fuzzy logic controllers do; and 6) it can be realized with low design complexity and small hardware overhead. Furthermore, the proposed approach has been applied to design three well-known nonlinear systems. The simulation and experimental results demonstrate the effectiveness of this design.

Activated human blood monocytes trigger the antitumor activity of blood polymorphonuclear cells.

The purpose of these studies was to determine whether human peripheral blood polymorphonuclear cells (PMNC) can be directly activated by lymphokines or bacterial products to lyse tumorigenic cells under in vitro conditions. Preparations of PMNC with different levels of purity were isolated by countercurrent elutriation. PMNC were incubated with recombinant interferon gamma and muramyldipeptide, with lipopolysaccharide, or with the synthetic lipopeptide CGP 31362. Only PMNC preparations containing 3-5% mononuclear cells lysed allogeneic melanoma cells. Homogeneous populations of PMNC did not. The addition of 5% monocytes to homogeneous populations of PMNC triggered PMNC-mediated tumor lysis. Cell-to-cell contact was not required in this process since culture supernatant of blood monocytes incubated with lipopolysaccharide (but not with medium) could trigger tumor cell lysis by PMNC. PMNC lysed both allogeneic tumorigenic (melanoma) and allogeneic nontumorigenic (fibroblast) cells, whereas activated monocytes lysed only tumorigenic cells. In conclusion, PMNC are triggered to lyse target cells by blood monocytes activated by bacterial products or by lymphokines.

Tumor necrosis factor and IL-1 associated with plasma membranes of activated human monocytes lyse monokine-sensitive but not monokine-resistant tumor cells whereas viable activated monocytes lyse both.

The purpose of our study was to determine some of the mechanisms involved in macrophage-mediated lysis of tumorigenic cells. A375 human melanoma cells (A375-R) resistant to lysis mediated by TNF and IL-1 were selected from the TNF- and IL-1-sensitive A375 parental melanoma cells subsequent to continuous (2 mo) exposure to rTNF. Peripheral blood monocytes isolated by centrifugal elutriation from healthy donors were incubated with rIFN-gamma and muramyl dipeptide, with a lipoprotein derived from Escherichia coli (CG-31362) or with LPS for 24 h. These activated monocytes lysed both the A375 (monokine-sensitive) and A375-R (monokine-resistant) melanoma cells. Activated tumoricidal macrophages fixed in 2% paraformaldehyde lysed only the TNF- and IL-1-sensitive A375 cells. These fixed monocytes contained both IL-1 and TNF activities as determined by D10 cell proliferation and L929 cytolysis assays, respectively. Nearly identical results were obtained with preparations of plasma membranes from activated human monocytes. Anti-IL-1 and/or anti-TNF sera neutralized the cytolysis of tumor cells mediated by free monokines, by fixed monocytes, or by plasma membrane preparations. In contrast, anti-TNF and/or anti-IL-1 sera did not inhibit tumor cell lysis by viable activated monocytes. We conclude that IL-1 and TNF molecules associated with the plasma membranes of activated monocytes mediate lysis of susceptible target cells. However, because activated monocytes lysed IL-1-and TNF-resistant target cells, molecules other than these monokines must also be involved in the antitumor activity of monocytes.

Destruction of tumor cells by monokines released from activated human blood monocytes: evidence for parallel and additive effects of IL-1 and TNF.

The incubation of human peripheral blood monocytes with endotoxins activates the cells to lyse tumorigenic targets directly and also induces the production and release into the culture medium of factors that produce lysis of mouse-transformed fibroblasts L-929 (tumor necrosis factor (TNF)-sensitive) and human A-375 melanoma cells (interleukin-1 (IL-1)- and TNF-sensitive). Immunoblotting analysis revealed that the culture medium of endotoxin-activated but not of control monocytes contained both IL-1 and TNF with a molecular weight of 17,000 daltons each. TNF activity was determined by lysis of L-929 cells, and IL-1 activity was measured by the proliferation of D-10 cells. The production of IL-1 and TNF was concentration-dependent, and the amounts of these monokines were paralleled. The antitumor activity of the culture supernates from endotoxin-treated monocytes was significantly decreased by incubation with heterologous antisera to IL-1, TNF, or both. Recombinant human IL-1 and TNF were used in parallel experiments and as positive controls. Each monokine used produced cytotoxic effects in susceptible targets. The combination of IL-1 and TNF, which more likely resembles culture supernates of activated macrophages, produced an additive antitumor cytotoxicity effect.

Quantitative fluorescent microassay for identification of antiproliferative compounds.

A reproducible and convenient microassay was developed by us to measure the antiproliferative activity of biological materials and anticancer drugs. The assay involved the labeling of target cells after their incubation with anticancer agents with the fluorescent vital dye hydroethidine at a dose of 28 micrograms/ml for 30 minutes. Once internalized into live cells, hydroethidine is dehydrogenated to ethidium, which then intercalates into DNA. Hydroethidine labeled the cells uniformly. The cells were lysed with detergent, and the relative fluorescence of this dye was monitored in a microfluorimeter at the speed of 30 seconds per 96-well plate. Because this assay is accurate and reproducible, does not present problems of disposal of labeling agents, and is extremely rapid, it should prove very useful for the screening of many potential anticancer agents with antiproliferative activity.

Digital feedback stabilization of a single-axial-mode CO2 TEA laser.

We have achieved long-term stability in producing high-power single-axial-mode CO2 laser pulses with a hybrid oscillator (TEA laser + low-pressure section) by using a novel digital feedback system that electronically adjusts cavity length.