Styrylquinolinium borates as donor–acceptor initiators for sensitized photopolymerization of TMPTA

Several photoredox pairs containing mono- and bicationic hemicyanine dyes have been evaluated as photoinitiators for free radical polymerization induced with an argon-ion laser irradiation. The tested photoredox couples are the pairs composed of the hemicyanine dye cations acting as electron acceptors and n-butyltriphenyl borate anions being the electron donors. The photoinitiating abilities of the series of monochromophoric stilbazolium borates, 4-(p-N,N-dialkylaminostyryl)quinolinium n-butyltriphenylborate, were compared to the photochemistry of structurally related, bicationic styrylquinolinium borates. The obtained results clearly documented that the dicationic photoinitiators exhibit a marked increase in the photoinitiation ability compared to the initiators consisting of a single charged hemicyanine dye.Our studies revealed also that the rate of photopolymerization depends on ΔG_el of electron transfer between borate anion and styrylquinolinium cation. The relationship between the rate of polymerization and the free energy of activation shows the dependence predicted by the classical theory of electron transfer.     

Recent Developments in the Application of Phosphorescent Iridium(III) Complex Systems

The recent developments in using iridium(III) complexes as phosphorescent emitters in electroluminescent devices, such as (white) organic light‐emitting diodes and light‐emitting electrochemical cells, are discussed. Additionally, applications in the emerging fields of molecular sensors, biolabeling, and photocatalysis are briefly evaluated. The basic strategies towards charged and non‐charged iridium(III) complexes are summarized, and a wide range of assemblies is discussed. Small‐molecule‐ and polymer‐based materials are under intense investigation as emissive systems in electroluminescent devices, and special emphasis is placed on the latter with respect to synthesis, characterization, electro‐optical properties, processing technologies, and performance.     

Aluminium and Its Complexes in Teas and Fruity Brew Samples,Speciation and Ions Determination by Ion Chromatography and High-Performance Liquid Chromatography–Fluorescence Analytical Methods

The paper presents results of aluminium determination in samples of black and fruit teas. Total aluminium concentration was determined along with the concentration of aluminium in a cup of tea in tea samples in two price groups (>1€ and <1€). Based on the conducted study, no differences were found in aluminium concentration in black and fruit teas depending on the price group. Developed ion chromatography method was applied to determine inorganic and organic ions in tea samples, especially those which may form complexes with aluminium: fluoride, sulphate, oxalate and citrate ions. Analysis by this method using ion chromatography allowed for the determination of 12 anions: F^?, HCOO^?, CH₃COO^?, NO₂ ^?, Br^?, NO₃ ^?; Cl^?, CH₂(COO)₂ ^2?, SO₄ ^2?, C₂O₄ ^2?, PO₄ ^3? and C₃H₅O(COO)₃ ^3? in the time of 40 min. Speciation analysis of aluminium was performed in optimised HPLC-fluorescence analytical system (with Lumogallion as a post-column reagent). It was observed that organic aluminium complexes are quickly degraded to form Al³⁺ which is the reason why speciation analysis in tea samples does not provide the full image of speciation distribution. Nevertheless, this developed method was successfully used in the determination of aluminium complexes with fluorides in tea samples.     

Determination of Metals and Metalloids in Wine Using Inductively Coupled Plasma Optical Emission Spectrometry and Mini-torch

In the present study, an inductively coupled plasma optical emission spectrometer ICPE-9820 with the mini-torch technology that significantly reduces the consumption of plasma gas to 7.0 L min^?1 was applied for the multielemental analysis of wine samples. Three sample preparation procedures (microwave digestion in closed vessels, acid digestion in open vessels in a water bath, both with HNO₃, and 1:10 dilution with deionized water) were compared for the determination of 15 elements in wines. In all wines analyzed, the lowest concentration was obtained for Li (0.06–0.09 mg L^?1) and the highest for K (475–995 mg L^?1). The concentration >1 mg L^?1 of B, Fe, and Na was determined in all wines analyzed by the three sample preparation procedures. The average concentrations found for the acid extracts for Al (1.31 mg L^?1) and Fe (3.40 mg L^?1) were higher in comparison to results of sample dilution (0.73 and 1.56 mg L^?1 respectively). The recoveries were between 88.2 and 110 %, 65.9 and 106 %, and 62.8 and 109 %, whereas the relative standard deviations (RSDs) varied between 0.04 and 4.62 %, 0.74 and 5.57 %, and 0.70 and 5.80 %, respectively, for the procedure of sample dilution, microwave digestion, and water bath digestion.     

Ultrastructural basis for the transition of cell death mode from apoptosis to necrosis in menadione-treated osteosarcoma 143B cells

Time-dependent ultrastructural changes of menadione-treated human osteosarcoma 143B cells were correlated with those in their stainability to Annexin V and propidium iodide (PI). Populations of both apoptotic (Annexin V(+)/PI(-)) and necrotic (Annexin V(+)/PI(+)) cells, judged by flow cytometry, began to increase at 2 h after menadione treatment. The former reached a maximum at 6 h followed by abrupt decreases thereafter, while the latter continued to increase. Electron microscopically, cells obtained at 6 h after the menadione treatment consisted of mixed populations of cells with typical apoptotic features and those with a mixture of apoptotic and necrotic features, while cells obtained at 8-24 h consisted exclusively of cells with a mixture of apoptotic and necrotic features. Thus, necrotic cells, as judged by flow cytometry, were in a transitional state of cell death mode from apoptosis to necrosis and are thus designated as 'intermediate cells'. Lack of apoptotic bodies, judged by flow cytometric analysis on sub-G1 nuclei and by electron microscopy in menadione-treated cells, suggested that the transition of cell death mode from apoptosis to necrosis occurred before the apoptotic processes were completed. Effects of N-acetylcysteine and Z-VAD-fmk on menadione-induced ultrastructural changes were also studied.     

Determination of the Phase Centers of Millimeter-Wave Horn Antennas Using a Holographic Interference Technique

In this paper, we discuss how a holographic interference technique can be applied in the experimental determination of the phase centers of non-standard horn antennas in the millimeter-waveband. The phase center is the point inside the horn from which the radiation appears to emanate when viewed from the far-field, and knowing its location is necessary for optimizing coupling efficiencies to quasi-optical systems. For non-standard horn designs, and other feed structures, the phase center may be difficult to reliably predict by simulation, in which case, before committing to antenna manufacture, there is a requirement for it to be determined experimentally. Although the phase center can be recovered by direct phase measurement of the far-field beam pattern, this usually involves expensive instrumentation such as a vector network analyzer for millimeter wave horn antennas. In this paper, we describe one inexpensive alternative, which is based on measuring the interference pattern in intensity between the radiation from the horn of interest and a reference beam derived from the same coherent source in an off-axis holography setup. The accuracy of the approach is improved by comparison with the interference pattern of a well-understood standard horn (such as a corrugated conical horn) in the same experimental setup. We present an example of the technique applied to a profiled smooth-walled horn antenna, which has been especially designed for cosmic microwave background (CMB) polarization experiments.     

Real-time fusion of endoscopic views with dynamic 3-D cardiac images: a phantom study

Minimally invasive robotically assisted cardiac surgical systems currently do not routinely employ 3-D image guidance. However, preoperative magnetic resonance and computed tomography (CT) images have the potential to be used in this role, if appropriately registered with the patient anatomy and animated synchronously with the motion of the actual heart. This paper discusses the fusion of optical images of a beating heart phantom obtained from an optically tracked endoscope, with volumetric images of the phantom created from a dynamic CT dataset. High quality preoperative dynamic CT images are created by first extracting the motion parameters of the heart from the series of temporal frames, and then applying this information to animate a high-quality heart image acquired at end systole. Temporal synchronization of the endoscopic and CT model is achieved by selecting the appropriate CT image from the dynamic set, based on an electrocardiographic trigger signal. The spatial error between the optical and virtual images is 1.4 +/- 1.1 mm, while the time discrepancy is typically 50-100 ms. Index Terms-Image guidance, image warping, minimally invasive cardiac surgery, virtual endoscopy, virtual reality.     

Transient thermal analysis of multilayered structures using Green's functions

This paper presents an approach to the analysis of transient thermal states in electronic circuits using an analytical solution of the heat equation. Fully three-dimensional analytical time dependent solutions are determined for multilayered structures with the help of Green's functions (GFs). The GFs required for the solution are found using a Galerkin-based integral method. The entire solution method is illustrated in detail using a practical example, where the results of transient thermal simulations of a real hybrid power module are compared with infrared measurements.