67 research outputs found
Enhancement in Electro-Optic Properties of Dynamic Scattering Systems through Addition of Dichroic Dyes
Electro-optic properties of dynamic scattering in homeotropically aligned
pure and dichroic dye-doped nematic liquid crystal samples are examined. The
optical properties of the two systems are quantified using transmission
properties of scattered and unscattered as a function of amplitude and
frequency of an applied voltage. Auto-correlation of the scattered signal at
different applied voltages is used to compare the decay times in the two
systems. Lastly, the histogram of the scattered signal reveals a wavevector
dependent large light scattering event. The dye-doped system shows a
significant enhancement of light blocking property in both normal and off-axis
light propagation. The characteristics of the system are compared to other
scattering technologies. The results suggest that dye-doped system can overcome
shortcomings in scattering based devices used for near-eye applications
Intermittent in-situ high-resolution X-ray microscopy of 400-nm porous glass under uniaxial compression: study of pore changes and crack formation
The properties of porous glasses and their field of application strongly
depend on the characteristics of the void space. Understanding the relationship
between their porous structure and failure behaviour can contribute to the
development of porous glasses with long-term reliability optimized for specific
applications. In the present work, we used X-ray computed tomography with
nanometric resolution (nano-CT) to image a controlled pore glass (CPG) with 400
nm-sized pores whilst undergoing uniaxial compression in-situ to emulate a
stress process. Our results show that in-situ nano-CT provides an ideal
platform for identifying the mechanisms of damage within glass with pores of
400 nm, as it allowed the tracking of the pores and struts change of shape
during compression until specimen failure. We have also applied computational
tools to quantify the microstructural changes within the CPG sample by mapping
the displacements and strain fields, and to numerically simulate the behaviour
of the CPG using a Fast Fourier Transform/phase-field method. Both experimental
and numerical data show local shear deformation, organized along bands,
consistent with the appearance and propagation of +/- 45 degrees cracks.Comment: 14 pages, 6 figure
Safety, Immunogenicity, and Protective Efficacy of Intradermal Immunization with Aseptic, Purified, Cryopreserved Plasmodium falciparum Sporozoites in Volunteers Under Chloroquine Prophylaxis
Immunization of volunteers under chloroquine prophylaxis by bites of *Plasmodium falciparum* sporozoite (PfSPZ)–infected mosquitoes induces > 90% protection against controlled human malaria infection (CHMI). We studied intradermal immunization with cryopreserved, infectious PfSPZ in volunteers taking chloroquine (PfSPZ
chemoprophylaxis vaccine [CVac]). Vaccine groups 1 and 3 received 3x monthly immunizations with 7.5 x 10^4
PfSPZ. Control groups 2 and 4 received normal saline. Groups 1 and 2 underwent CHMI (#1) by mosquito bite 60
days after the third immunization. Groups 3 and 4 were boosted 168 days after the third immunization and
underwent CHMI (#2) 137 days later. Vaccinees (11/20, 55%) and controls (6/10, 60%) had the same percentage of
mild to moderate solicited adverse events. After CHMI #1, 8/10 vaccinees (group 1) and 5/5 controls (group 2)
became parasitemic by microscopy; the two negatives were positive by quantitative real-time polymerase chain
reaction (qPCR). After CHMI #2, all vaccinees in group 3 and controls in group 4 were parasitemic by qPCR.
Vaccinees showed weak antibody and no detectable cellular immune responses. Intradermal immunization with up
to 3 x 10^5 PfSPZ-CVac was safe, but induced only minimal immune responses and no sterile protection against Pf
CHMI.
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Role of Oxidized Lipids in Pulmonary Arterial Hypertension
Pulmonary arterial hypertension (PAH) is a multifactorial disease characterized by interplay of many cellular, molecular, and genetic events that lead to excessive proliferation of pulmonary cells, including smooth muscle and endothelial cells; inflammation; and extracellular matrix remodeling. Abnormal vascular changes and structural remodeling associated with PAH culminate in vasoconstriction and obstruction of pulmonary arteries, contributing to increased pulmonary vascular resistance, pulmonary hypertension, and right ventricular failure. The complex molecular mechanisms involved in the pathobiology of PAH are the limiting factors in the development of potential therapeutic interventions for PAH. Over the years, our group and others have demonstrated the critical implication of lipids in the pathogenesis of PAH. This review specifically focuses on the current understanding of the role of oxidized lipids, lipid metabolism, peroxidation, and oxidative stress in the progression of PAH. This review also discusses the relevance of apolipoprotein A-I mimetic peptides and microRNA-193, which are known to regulate the levels of oxidized lipids, as potential therapeutics in PAH
Enhancement in electro-optic properties of dynamic scattering systems through addition of dichroic dyes
Electro-optic properties of dynamic scattering in homeotropically aligned pure and dichroic dye doped nematic liquid crystal samples are examined. The optical properties of the two systems are quantified using transmission properties of scattered and unscattered as a function of amplitude and frequency of an applied voltage. Auto-correlation of the scattered signal at different applied voltages is used to compare the decay times in the two systems. Lastly, histogram of the scattered signal reveals a wavevector dependent large light scattering event. The dye doped system shows a significant enhancement of light blocking property in both normal and off-axis light propagation. The characteristics of the system are compared to other scattering technologies. The results suggest that dye doped system can overcome shortcomings in scattering based devices used for near eye applications
ON THE SEPARABILITY BETWEEN SIGNAL AND NOISE IN SINGULAR SPECTRUM ANALYSIS
The optimal value of the window length in singular spectrum analysis (SSA) is considered with respect to the concept of separability between signal and noise component, from the theoretical and practical perspective. The theoretical results confirm that for a wide class of time series of length N, the suitable value of this parameter is median{1, …, N}. The results of both simulated and real data verify the effectiveness of the theoretical results. The theoretical results obtained here coincide with those obtained previously from the empirical point of view
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