A photophoretic-trap volumetric display.

Free-space volumetric displays, or displays that create luminous image points in space, are the technology that most closely resembles the three-dimensional displays of popular fiction. Such displays are capable of producing images in 'thin air' that are visible from almost any direction and are not subject to clipping. Clipping restricts the utility of all three-dimensional displays that modulate light at a two-dimensional surface with an edge boundary; these include holographic displays, nanophotonic arrays, plasmonic displays, lenticular or lenslet displays and all technologies in which the light scattering surface and the image point are physically separate. Here we present a free-space volumetric display based on photophoretic optical trapping that produces full-colour graphics in free space with ten-micrometre image points using persistence of vision. This display works by first isolating a cellulose particle in a photophoretic trap created by spherical and astigmatic aberrations. The trap and particle are then scanned through a display volume while being illuminated with red, green and blue light. The result is a three-dimensional image in free space with a large colour gamut, fine detail and low apparent speckle. This platform, named the Optical Trap Display, is capable of producing image geometries that are currently unobtainable with holographic and light-field technologies, such as long-throw projections, tall sandtables and 'wrap-around' displays.

Body-of-revolution finite-difference time-domain modeling of hybrid-plasmonic ring resonators.

Development of a computational technique for the analysis of quasi-normal modes in hybrid-plasmonic resonators is the main goal of this research. Because of the significant computational costs of this analysis, one has to take various symmetries of these resonators into account. In this research, we consider cylindrical symmetry of hybrid-plasmonic ring resonators and implement a body-of-revolution finite-difference time-domain (BOR-FDTD) technique to analyze these resonators. We extend the BOR-FDTD method by proposing two different sets of auxiliary fields to implement multi-term Drude-Lorentz and multi-term Lorentz models in BOR-FDTD. Moreover, we utilize the filter-diagonalization method to accurately compute the complex resonant frequencies of the resonators. This approach improves numerical accuracy and computational time compared to the Fourier transform method used in previous BOR-FDTD methods. Our numerical analysis is verified by a 2D axisymmetric solver in COMSOL Multiphysics.

Anisotropic leaky-mode modulator for holographic video displays.

Every holographic video display is built on a spatial light modulator, which directs light by diffraction to form points in three-dimensional space. The modulators currently used for holographic video displays are challenging to use for several reasons: they have relatively low bandwidth, high cost, low diffraction angle, poor scalability, and the presence of quantization noise, unwanted diffractive orders and zero-order light. Here we present modulators for holographic video displays based on anisotropic leaky-mode couplers, which have the potential to address all of these challenges. These modulators can be fabricated simply, monolithically and at low cost. Additionally, these modulators are capable of new functionalities, such as wavelength division multiplexing for colour display. We demonstrate three enabling properties of particular interest-polarization rotation, enlarged angular diffraction, and frequency domain colour filtering-and suggest that this technology can be used as a platform for low-cost, high-performance holographic video displays.

Isomeric Character of the Lowest Observed 4

Previous experiments observed a 4^{+} state in the N=28 nucleus ^{44}S and suggested that this state may exhibit a hindered E2-decay rate, inconsistent with being a member of the collective ground state band. We populate this state via two-proton knockout from a beam of exotic ^{46}Ar projectiles and measure its lifetime using the recoil distance method with the GRETINA γ-ray spectrometer. The result, 76(14)_{stat}(20)_{syst} ps, implies a hindered transition of B(E2;4^{+}→2_{1}^{+})=0.61(19) single-particle or Weisskopf units strength and supports the interpretation of the 4^{+} state as a K=4 isomer, the first example of a high-K isomer in a nucleus of such low mass.

Evolution of collectivity in 72Kr: evidence for rapid shape transition.

The transition rates from the yrast 2+ and 4+ states in the self-conjugate 72Kr nucleus were studied via lifetime measurements employing the GRETINA array with a novel application of the recoil-distance method. The large collectivity observed for the 4+→2+ transition suggests a prolate character of the excited states. The reduced collectivity previously reported for the 2+→0+ transition was confirmed. The irregular behavior of collectivity points to the occurrence of a rapid oblate-prolate shape transition in 72Kr, providing stringent tests for advanced theories to describe the shape coexistence and its evolution.

Effect of two-photon absorption on trapping of plasmonic nanoparticles.

In this paper, we introduce a theoretical framework for optical trapping that integrates nonlinear polarization within the dipole approximation. This theory represents the most comprehensive analytic model to date capable of resolving the discrepancies between the observed and simulated trapping of plasmonic nanoparticles. Our theory elucidates how two-photon absorption can account for the stable trapping of gold nanoparticles, including their longitudinal stability, especially near their plasmon resonance. Furthermore, the experimentally observed split potential wells in the transverse plane, which are attributed to two-photon absorption, are in close agreement with our model's predictions. Finally, this study provides new insights into the mechanism of optical trapping under conditions of intense light-matter interactions.

Serratia entomophila bet gene induction and the impact of glycine betaine accumulation on desiccation tolerance.

AIMS: The genes involved in choline transport and oxidation to glycine betaine in the biopesticidal bacterium Serratia entomophila were characterized, and the potential of osmoprotectants, coupled with increased NaCl concentrations, to improve the desiccation tolerance of this species was investigated. METHODS AND RESULTS: Serratia entomophila carries sequences similar to the Escherichia coli betTIBA genes encoding a choline transporter and dehydrogenase, a betaine aldehyde dehydrogenase and a regulatory protein. Disruption of betA abolished the ability of Ser. entomophila to utilize choline as a carbon source. Quantitative reverse-transcriptase PCR analysis revealed that betA transcription was reduced compared to that of the upstream genes in the operon, and that NaCl and choline induced bet gene expression. Glycine betaine and choline increased the NaCl tolerance of Ser. entomophila, and osmotically preconditioned cultures survived better than control cultures following desiccation and immediately after application to agricultural soil. CONCLUSIONS: Addition of glycine betaine and NaCl to growth medium can greatly enhance the desiccation survival of Ser. entomophila, and its initial survival in soil. SIGNIFICANCE AND IMPACT OF THE STUDY: Serratia entomophila is sensitive to desiccation and does not persist under low soil moisture conditions. Techniques described here for enhancing the desiccation survival of Ser. entomophila can be used to improve formulations of this bacterium, and allow its application under a wider range of environmental conditions.

Direct binding to and tyrosine phosphorylation of the alpha subunit of the type I interferon receptor by p135tyk2 tyrosine kinase.

Binding of type I interferons (IFNs) to their receptors induces rapid tyrosine phosphorylation of multiple proteins, including the alpha and beta subunits of the receptor, the polypeptides that form the transcriptional activator ISGF3 alpha (Stat113, Stat84, and Stat91), and the p135tyk2 and Jak-1 tyrosine kinases. In this report, we demonstrate that the alpha subunit of the type I IFN receptor (IFN-R) corresponds to the product of a previously cloned receptor subunit cDNA and, further, that the p135tyk2 tyrosine kinase directly binds and tyrosine phosphorylates this receptor subunit. Glutathione S-transferase (GST) fusion proteins encoding the different regions of the cytoplasmic domain of the alpha subunit can bind the p135tyk2 contained in human cell lysates. The association between the alpha subunit and Tyk2 was demonstrated by immunoblotting with anti-Tyk2 and antiphosphotyrosine antibodies and by using an in vitro kinase assay. Analogous experiments were then performed with recombinant baculoviruses encoding constitutively active Jak family tyrosine kinases. In this case, p135tyk2, but not Jak-1 or Jak-2 protein, binds to the GST-IFN-R proteins, suggesting that the interaction between these two proteins is both direct and specific. We also demonstrate that Tyk2, from extracts of either IFN alpha-treated human cells or insect cells infected with the recombinant baculoviruses, can catalyze in vitro phosphorylation of GST-IFN-R protein in a specific manner. Deletion mutants of the GST-IFN-R protein were used to localize both the binding and tyrosine phosphorylation site(s) to a 46-amino-acid juxtamembrane region of the alpha subunit, which shows sequence homology to functionally similar regions of other cytokine receptor proteins. These data support the hypothesis that the Tyk2 protein functions as part of a receptor complex to initiate intracellular signaling in response to type I IFNs.

Frequency division color characterization apparatus for anisotropic leaky mode light modulators.

This paper presents an optical apparatus for characterizing frequency multiplexing of color in leaky mode, anisotropic waveguide modulators. This type of characterization is particularly useful for informing the design of full color holographic video displays. The primary function of the apparatus is to map the frequency response and angular overlap of red, green, and blue outputs. The apparatus also allows measurements of other parameters such as scan center frequency, optical and RF bandwidth, and scan linearity.

An internal ribosome entry site in the 5' untranslated region of epidermal growth factor receptor allows hypoxic expression.

The expression of epidermal growth factor receptor (EGFR/ERBB1/HER1) is implicated in the progress of numerous cancers, a feature that has been exploited in the development of EGFR antibodies and EGFR tyrosine kinase inhibitors as anti-cancer drugs. However, EGFR also has important normal cellular functions, leading to serious side effects when EGFR is inhibited. One damaging characteristic of many oncogenes is the ability to be expressed in the hypoxic conditions associated with the tumour interior. It has previously been demonstrated that expression of EGFR is maintained in hypoxic conditions via an unknown mechanism of translational control, despite global translation rates generally being attenuated under hypoxic conditions. In this report, we demonstrate that the human EGFR 5' untranslated region (UTR) sequence can initiate the expression of a downstream open reading frame via an internal ribosome entry site (IRES). We show that this effect is not due to either cryptic promoter activity or splicing events. We have investigated the requirement of the EGFR IRES for eukaryotic initiation factor 4A (eIF4A), which is an RNA helicase responsible for processing RNA secondary structure as part of translation initiation. Treatment with hippuristanol (a potent inhibitor of eIF4A) caused a decrease in EGFR 5' UTR-driven reporter activity and also a reduction in EGFR protein level. Importantly, we show that expression of a reporter gene under the control of the EGFR IRES is maintained under hypoxic conditions despite a fall in global translation rates.

The immunopathology of siliconosis. History, clinical presentation, and relation to silicosis and the chemistry of silicon and silicone.

Recent evidence confirms the fundamental involvement of the human immune system in the reaction to implantation of silicone-based medical devices. An as yet-to-be particularized epitope of many complex substances sharing siloxane structures is presented through the MHC-II apparatus with development and retention of T cell memory. This memory can be tested for in practical terms using one or more forms of silica, which links the immuno-histopathology and autoimmune attributes of "silicosis" with those of "siliconosis." The lesions of siliconosis are typical of those for persistent antigens and delayed, cell mediated hypersensitivity. The basic descriptive pathology of the reaction to silicone has been known since soon after introduction of silicones in medical procedures, with the exception of some details related to the more recent discoveries on the role of cytokines in the immunopathic process. The clinical consequences of siliconosis are common and can be severe in some individuals implanted with silicone devices.

DNA array analysis in a Microsoft Windows environment.

Microsoft Windows-based computers have evolved to the point that they provide sufficient computational and visualization power for robust analysis of DNA array data. In fact, smaller laboratories might prefer to carry out some or all of their analyses and visualization in a Windows environment, rather than alternative platforms such as UNIX. We have developed a series of manually executed macros written in Visual Basic for Microsoft Excel spreadsheets, that allows for rapid and comprehensive gene expression data analysis. The first macro assigns gene names to spots on the DNA array and normalizes individual hybridizations by expressing the signal intensity for each gene as a percentage of the sum of all gene intensities. The second macro streamlines statistical consideration of the confidence in individual gene measurements for sets of experimental replicates by calculating probability values with the Student's t test. The third macro introduces a threshold value, calculates expression ratios between experimental conditions, and calculates the standard deviation of the mean of the log ratio values. Selected columns of data are copied by a fourth macro to create a processed data set suitable for entry into a Microsoft Access database. An Access database structure is described that allows simple queries across multiple experiments and export of data into third-party data visualization software packages. These analysis tools can be used in their present form by others working with commercial E. coli membrane arrays, or they may be adapted for use with other systems. The Excel spreadsheets with embedded Visual Basic macros and detailed instructions for their use are available at http://www.ou.edu/microarray.

Increased basal levels of free plasminogen activator activity found in human aqueous humor.

PURPOSE: To quantify the basal free t-PA activity in human aqueous humor. METHODS: Human aqueous humor obtained by simplified pipette paracentesis at cataract surgery was tested for free t-PA activity in a revised 15-hour amidolytic assay using a t-PA standard curve (n = 15). Total antigenic levels of PAI-1, the principal PA inhibitor, were determined using an ELISA kit. The available PAI-1 activity was tested indirectly using anti-human PAI-1 antibody blocking before t-PA activity assay (n = 11). Plasminogen activator type was determined by anti-human t-PA and urokinase (u-PA) antibody blocking before activity assay (n = 7). RESULTS: Free PA activity ranged widely (0.072 to 0.47 IU/ml; mean, 0.20 +/- 0.10 IU/ml) and was almost completed inactivated (> or = 89%) by antibody against human t-PA but not by the u-PA antibody. PAI-1 total antigen also ranged widely between (0.25 to 8.0 ng/ml; mean, 2.25 +/- 2.54 ng/ml). However, pretreatment of samples with PAI-1 antibody or by acidification (pH 3.2) to inactivate inhibitors did not increase t-PA activity levels. CONCLUSIONS: A basal-free t-PA activity, which is predominantly t-PA, is present in human aqueous humor at approximately 20 times higher levels than previously found with an earlier assay. This activity is estimated to represent roughly 10% of total released t-PA antigen. PAI-1 is present in aqueous humor at levels considerably lower than reported values for plasma in a predominantly PA-complexed or inactive form.

Tissue plasminogen activator activity in human aqueous humor.

PURPOSE: To determine the levels of free plasminogen activator activity in human aqueous humor and to identify the type of activity (i.e., tissue-type t-PA or urokinase-type u-PA) that is responsible. METHODS: Aqueous humor was obtained by a simplified pipette paracentesis before cataract surgery in 31 subjects, ages 57 to 93 years. Levels of plasminogen activator activity were determined using a modified 17-hour specific amidolytic assay. The type of plasminogen activator was investigated in selected samples based on its dependence on soluble fibrin, inhibition by amiloride, and specific antibody blocking. Activity-antigen ratios were compared in seven samples. RESULTS: Plasminogen activator (PA) activity was present in all samples tested. PA activity ranged widely between 0.54 and 26.7 mIU/ml, with a mean value of 10.8 +/- 8.1 mIU/ml. Soluble fibrin, a known stimulator of tissue-type plasminogen activator (t-PA), was required in the assay system. Its absence decreased the measured activity by more than 90%. Amiloride, a known inhibitor of urokinase-type PA, had little or no effect in selected samples tested. The activity was blocked by anti-human t-PA antibodies but not by antibodies against human u-PA, further defining the type of PA responsible for the detected activity. t-PA antigen levels showed less variation among individuals than did activity levels. Antigen-activity ratios ranged between 89 and 552. CONCLUSION: Plasminogen activator activity is present in the human aqueous humor in measurable quantities. The type of PA activity present is almost exclusively t-PA. t-PA activity varies more widely than antigen, as is the case in plasma.

Adenosine diphosphate stimulates the endothelial release of tissue-type plasminogen activator but not von Willebrand factor from isolated-perfused rat hind limbs.

The acute release of tissue-type plasminogen activator (t-PA) activity and of von Willebrand Factor (vWF) antigen from vascular endothelium was studied ex vivo using the rat hindquarter isolated perfusion model. The release of these proteins has been reported to occur simultaneously in response to a variety of endothelial cell agonists including bradykinin, thrombin and platelet activating factor. It has therefore been suggested that similar endothelial cell pathways and mechanisms are involved in the release of t-PA and vWF in vivo. This paper shows that the releases of t-PA and of vWF are not always closely linked and may depend on the agonist utilized to effect release. In our hands, the bradykinin-induced release of these proteins appears to be essentially identical, but this is not true for adenosine diphosphate (ADP). Rather, ADP is capable of causing the acute release of t-PA without the simultaneous release of vWF in the ex vivo rat hindquarter model. This indicates that the bradykinin- and ADP-induced pathways for t-PA release are probably distinct and that the releases of t-PA and vWF are not as closely linked as previously believed.

Lymphocyte response to silica among offspring of silicone breast implant recipients.

The current study evaluated immune response to silicon dioxide in children born to women with silicone breast implants. In part one of the study, the T lymphocytes of 21 of 24 such children were significantly stimulated by silicon dioxide (silica). Part two consisted of eleven children, four born preimplantation and seven born postimplantation. None of the preimplant offspring showed T cell responses to silica; five of the seven postimplant children were positive for T cell memory for silica. Part three was a blinded study based on statistically significant differences in T cell stimulation with silicon dioxide between postimplant children and controls. These findings indicate a common immune reaction, that of T cell memory, occurs in mothers and their children born after exposure to silicone mammary implants placed prior to pregnancy. Since not all such children were breast fed the result favors transplacental passage of immunogens such as silicone oligomers or through maternofetal cellular traffic.

Effect of LFA-1beta antibody on leukocyte adherence in response to hemorrhagic shock in rats.

The activation and adherence of leukocytes to the venular endothelium are critical steps in the pathogenesis of generalized microvascular injury following hemorrhagic shock. Previous studies have shown that the integrins CD11/CD18 play a significant role in this interaction. The purpose of this study is to examine the efficacy of anti-LFA-1beta, an antibody to CD11a/CD18, in attenuating leukocyte adherence before, during, and after hemorrhagic shock. Following a control period, blood was withdrawn to reduce the mean arterial pressure to 40 mm Hg for 30 min in urethane-anesthetized rats. Mesenteric venules in a transilluminated segment of the small intestines were examined to quantitate leukocyte adherence using intravital microscopy. In sham-operated rats (control), there was minimal to no leukocyte adherence throughout the experiment. Hemorrhagic shock resulted in significant leukocyte adherence during resuscitation (10.8 +/- 1.7 cells/100 microm, P < 0.01) when compared to control. Anti-LFA-1beta, when given before hemorrhagic shock, significantly attenuated leukocyte adherence during resuscitation (1.1 +/- 0.8, P < 0.01) when compared with hemorrhagic shock alone. This protective effect of anti-LFA-1beta on leukocyte adherence was even demonstrated when it was given during (1.6 +/- 0.3, P < 0.01) and 10 min after hemorrhagic shock (5.8 +/- 0.4, P < 0.05). These results suggest that anti-LFA-1beta may be of potential therapeutic benefit against microvascular injury caused by hemorrhagic shock.

Leukocyte adherence and sequestration following hemorrhagic shock and total ischemia in rats.

The pathogenesis of generalized microvascular injury following hemorrhagic shock and total ischemia appears to be dependent on leukocytes interacting with the venular endothelium. The purpose of this study was to compare leukocyte adherence and sequestration following hemorrhagic shock with that of total ischemia in the small bowel mesentery of rats. Leukocyte adherence and sequestration was measured by direct visualization in vivo using intravital microscopy. In addition, sequestration was also quantitated by measuring tissue levels of myeloperoxidase, a marker of leukocyte infiltration. Mean arterial blood pressure was decreased to 40 mm Hg for 30 min (hemorrhagic shock group). In the total ischemia group, both the superior and inferior mesenteric arteries were clamped for 30 min followed by reperfusion. Hemorrhagic shock (9.4+/-1.5 cell/100 microm) and total ischemia (8.3+/-3 cell/100 microm) caused a statistically significant increases in leukocyte adherence 60 min postinsult as compared with controls (.9+/-1.5 cell/100 microm). However, the increase in leukocyte adherence appeared earlier and to a greater degree initially following total ischemia. Leukocyte sequestration as measured by intravital microscopy was significant only after total ischemia [(24.6+/-1.7 cell/(100 microm)2; p<.01] and not hemorrhagic shock [3.4+/-.6 cell/(100 microm)2] versus controls [2.2+/-.2 cell/(100 microm)2]. This difference in sequestration was also confirmed by tissue levels of myeloperoxidase. The results of this study suggest that the microvascular response following hemorrhagic shock is different than that of total ischemia, and caution is warranted when extrapolating the experimental results of one to the other.

Seroepidemiology of Legionella pneumophila. A study of adults from Memphis, Tennessee, U. S. A.

Sera of 1,000 adults (aged 50 to 104) from Memphis, Tennessee were tested by the microagglutination procedure for antibodies to Legionella pneumophila (Philadelphia 1 strain). Of the 1,000 sera tested, 53 (5.3%) had titers of 1:16 or greater to L. pneumophila.

Legionnaires' disease bacterium: a non-endospore-former.

This investigation was done to determine whether dipicolinic acid was present in the Legionnaires' disease bacterium. A colorimetric assay for dipicolinic acid was done and the results for the bacterium were compared with those obtained for Escherichia coli and Bacillus subtilis. Dipicolinic acid was not detected in the Legionnaires' disease bacterium. This demonstrated that the bacterium was unable to produce typical bacterial endospores under the experimental conditions examined.