Security devices based on liquid crystals doped with a colour dye

Liquid crystal properties make them useful for the development of security devices in applications of authentication and detection of fakes. Induced orientation of liquid crystal molecules and birefringence are the two main properties used in security devices. Employing liquid crystal and dichroic colorants, we have developed devices that show, with the aid of a polarizer, multiple images on each side of the device. Rubbed polyimide is used as alignment layer on each substrate of the LC cell. By rubbing the polyimide in different directions in each substrate it is possible to create any kind of symbols, drawings or motifs with a greyscale; the more complex the created device is, the more difficult is to fake it. To identify the motifs it is necessary to use polarized light. Depending on whether the polarizer is located in front of the LC cell or behind it, different motifs from one or the other substrate are shown. The effect arises from the dopant colour dye added to the liquid crystal, the induced orientation and the twist structure. In practice, a grazing reflection on a dielectric surface is polarized enough to see the effect. Any LC flat panel display can obviously be used as backlight as well.

Richard Baxter Foster Letter to his wife June 4 1865

Letter from Richard Baxter Foster to his wife Lucy from Brownsville, Texas on June 4 1865.

Richard Baxter Foster Letter to his wife (October 4, 1865?)

Letter from Richard Baxter Foster to his wife Lucy one month after he submitted his request to be discharged from service.

2.4 W. Sherman Savage, Lincoln University History Professor, 1921-60

Gaines studied History and Education at Lincoln and was frequently seen in Memorial Hall chatting with his mentors in the History Department, Drs. W. Sherman Savage and Lorenzo Greene about his future after graduation.

1.4 Gaines Family Home at 3932 Weest Belle Place, St. Louis, Missouri

Following the death of Lloyd's father, his family, the size of which is reported to be anywhere from five to 11 siblings, moved to St. Louis, Missouri in 1926, settling in the city's Central West End neighborhood.

3.4 MU registrar informed Lloyd Gaines that he was not eligible to attend the University of Missouri due to the fact that Gaines was a Negro

After several weeks, Gaines finally received a reply to his application from Sy Woodson Canada, the MU registrar. Canada informed him that he was not eligible to attend the University of Missouri due to the fact that Gaines was a Negro and it was in conflict of Missouri state law for MU to admit him.

1.4 Henry D. Espy, NAACP Attorney, Saint Louis, Missouri

Houston, Redmond and St. Louis attorney Cecil Espy began forming their case. The NAACP, on behalf of Lloyd Gaines, petitioned for a writ of mandamus in the Boone County Circuit Court.

2.4 Judge W. M. Dinwiddie Boone County, Missouri, 13th Circuit Court

Two weeks later, Judge Dinwiddie issued his decision in favor of Canada and the University. Houston was expecting this and appealed to the Missouri Supreme Court.

3.4 United States Supreme Court 1938

Gaines’ legal team, led by Houston, had faith in the justice system of the United States and anticipated getting a fair trial at the federal level. So far, all decisions had occurred in Missouri, a state with a segregated system.The fact that Gaines v Canada had reached the Supreme Court was promising indeed. It was rare that any case involving African-Americans would be considered by the highest court in the land. President Franklin D. Roosevelt had been appointing Justices that were more willing to consider cases concerned with civil rights. On November 9, 1938, the Supreme Court of the United States heard arguments in the Gaines v Canada case. The defense was unmoved by the rude treatment and made their presentation with professionalism and aplomb. Houston’s argument remained steadfast; not only was the state of Missouri’s statute concerning out-of-state tuition for blacks in violation of the 14th Amendment, but the very idea of segregation itself violated the Constitution. William Hogsett, the attorney for the University of Missouri, countered that the school was merely following state laws. The MU legal team was flustered as questions from the bench forced them to correct overstatements regarding Missouri’s “generosity to Negro students”. With crossed fingers and high hopes, the Gaines legal team rested their case and awaited the verdict. Meanwhile, Lloyd Gaines was still in Michigan. Lloyd held a W.P.A. job as a Civil Service Clerk and was in constant contact with his family and attorneys. His mood in his correspondence was hopeful and positive.

1.4 Lloyd C. Stark, 39th Governor of State of Missouri, 1937-1941

After weeks of debate Taylor’s proposal, House Bill No. 195 was passed and signed by Governor Lloyd Stark.

2.4 "The Strange Disappearance of Lloyd Gaines"

The May 1951 Ebony Magazine Article "The Strange Disappearance of Lloyd Gaines"

3.4 University of Missouri Doctor of Law Degree to Lloyd Lionel Gaines

On May 13, 2006, University of Missouri awarded Lloyd Gaines Doctor of Law degree.

Preferential Zn2+ influx through Ca2+-permeable AMPA/kainate channels triggers prolonged mitochondrial superoxide production

Synaptically released Zn2+ can enter and cause injury to postsynaptic neurons. Microfluorimetric studies using the Zn2+-sensitive probe, Newport green, examined levels of [Zn2+]i attained in cultured cortical neurons on exposure to N-methyl-d-asparte, kainate, or high K+ (to activate voltage-sensitive Ca2+ channels) in the presence of 300 μM Zn2+. Indicating particularly high permeability through Ca2+-permeable α-amino3-hydroxy-5-methyl-4-isoxazolepropionic-acid/kainate (Ca-A/K) channels, micromolar [Zn2+]i rises were observed only after kainate exposures and only in neurons expressing these channels [Ca-A/K(+) neurons]. Further studies using the oxidation-sensitive dye, hydroethidine, revealed Zn2+-dependent reactive oxygen species (ROS) generation that paralleled the [Zn2+]i rises, with rapid oxidation observed only in the case of Zn2+ entry through Ca-A/K channels. Indicating a mitochondrial source of this ROS generation, hydroethidine oxidation was inhibited by the mitochondrial electron transport blocker, rotenone. Additional evidence for a direct interaction between Zn2+ and mitochondria was provided by the observation that the Zn2+ entry through Ca-A/K channels triggered rapid mitochondrial depolarization, as assessed by using the potential-sensitive dye tetramethylrhodamine ethylester. Whereas Ca2+ influx through Ca-A/K channels also triggers ROS production, the [Zn2+]i rises and subsequent ROS production are of more prolonged duration.

CD3-mediated activation of tumor-reactive lymphocytes from patients with advanced cancer

Lymphocytes from blood or tumors of patients with advanced cancer did not proliferate and produced very low levels of tumor necrosis factor and IFN-γ when cultured with autologous tumor cells. Proliferation and lymphokine production dramatically increased in the presence of beads conjugated with mAbs to CD3 plus mAbs to CD28 and/or CD40, and the lymphocytes destroyed the tumor cells. Expression density of CD3 concomitantly increased from low to normal levels. Furthermore, beads providing a CD3 signal (in combination with CD28 or CD28 plus CD40) gave partial protection against the inhibitory effect of transforming growth factor type β1 on lymphocyte proliferation and production of tumor necrosis factor and IFN-γ. MHC class I-restricted cytolytic T cells lysing autologous tumor cells in a 4-h Cr51 release assay were generated when peripheral blood leukocytes were activated in the presence of autologous tumor cells and anti-CD3/CD28 or anti-CD3/CD28/CD40 beads. Experiments performed in a model system using anti-V-β1 or anti-V-β2 mAbs to activate subsets of T cells expressing restricted T cell receptor showed that lymphocytes previously activated by anti-V-β can respond to CD3 stimulation with vigorous proliferation and lymphokine production while retaining their specificity, also in the presence of transforming growth factor type β1. Our results suggest that T lymphocytes from cancer patients can proliferate and form Th1 type lymphokines in the presence of autologous tumor cell when properly activated, and that antigen released from killed tumor cells and presented by antigen-presenting cells in the cultures facilitates the selective expansion of tumor-directed, CD8+ cytolytic T cells.

Use of a New Tetrazolium-Based Assay to Study the Production of Superoxide Radicals by Tobacco Cell Cultures Challenged with Avirulent Zoospores of Phytophthora parasitica var nicotianae1

The relationship between the production of reactive oxygen species and the hypersensitive response (HR) of tobacco (Nicotiana tabacum L.) toward an incompatible race of the Oomycete Phytophthora parasitica var nicotianae has been investigated. A new assay for superoxide radical (O2−) production based on reduction of the tetrazolium dye sodium,3′-(1-[phenylamino-carbonyl]-3,4-tetrazolium)-bis(4-methoxy-6-nitro) benzene-sulfonic acid hydrate (XTT) has enabled the quantitative estimation of perhydroxyl/superoxide radical acid-base pair (HO2·/O2−) production during the resistant response. Tobacco suspension cells were inoculated with zoospores from compatible or incompatible races of the pathogen. Subsequent HO2·/O2− production was monitored by following the formation of XTT formazan. In the incompatible interaction only, HO2·/O2− was produced in a minor burst between 0 and 2 h and then in a major burst between 8 and 10 h postinoculation. During this second burst, rates of XTT reduction equivalent to a radical flux of 9.9 × 10−15 mol min−1 cell−1 were observed. The HO2·/O2− scavengers O2− dismutase and Mn(III)desferal each inhibited dye reduction. An HR was observed in challenged, resistant cells immediately following the second burst of radical production. Both scavengers inhibited the HR when added prior to the occurrence of either radical burst, indicating that O2− production is a necessary precursor to the HR.