1,4-dialkoxy-2,5-bis[2-(thien-2-yl)ethenyl]benzenes as promising materials for laser optical limiters

A new promising organic chromophore for two-photon laser absorption at 1064 nm with 1,4-diethoxy-2,5-bis[2-(5-methylthien-2-yl)ethenyl]benzene (A-C) was synthesized. We have performed evaluations of the two-photon absorption for these chromophores incorporated into the polymer matrices. Following the obtained quantum chemical data, we have performed quantum chemical simulations of the third-order susceptibilities for the investigated chrompophore incorporated into the PMMA matrices. The calculations were done within the three-level model. We have established that the experimentally calculated data are a bit less than theoretically calculated; however, the general tendency of their changes shows a good coincidence. The maximally achieved value of the TPA is equal to about 59.2 cm/GW at wavelength 1064 nm, which, together with their high photothermal stabilities, make them good candidates for optical-limiting processes.     

Confirmation of drug delivery after liver chemoembolization: direct tissue doxorubicin measurement by UHPLC‐MS‐MS

Because liver cancer is rarely suitable for surgery, transcatheter arterial chemoembolization (TACE) is used for palliative therapy. In this procedure, an emulsion of doxorubicin in iodized oil is injected directly into liver tumors through a catheter positioned within the artery supplying blood flow to the tumor. At present, there is limited understanding of factors affecting the delivery and dispersion of doxorubicin within treated tumors during TACE. This study addresses the development and application of an ultrahigh‐pressure liquid chromatography–tandem mass spectrometry (UHPLC‐MS‐MS) method for rapid confirmation of drug delivery after TACE in a rabbit VX2 liver cancer model. Doxorubicin levels in liver tumors were measured using UHPLC‐MS‐MS and compared with computed tomography measured levels of iodized oil, a metric used clinically to indicate drug delivery. We found that tissue drug levels determined using UHPLC‐MS‐MS did not correlate with the regional iodized oil concentration (vehicle) within tumors following TACE, suggesting that chemotherapeutic drugs like doxorubicin spread throughout tumors, and that lack of iodized oil staining in portions of a tumor does not necessarily indicate inadequate therapy during TACE. Copyright © 2012 John Wiley & Sons, Ltd.     

On isotropic states in α-LiNH4SO4 crystals

The spectral and baric dependences of the birefringence of α-LiNH₄SO₄ crystals are studied. It is found that the birefringence is rather sensitive to uniaxial compressions. A baric shift of the isotropic point to longer or shorter wavelengths depending on the uniaxial compression direction is observed and a generalized temperature-spectral-baric diagram of the isotropic state is plotted. A possibility of the appearance of a pseudoisotropic state under the action of uniaxial pressure σ _z or simultaneous pressures σ _x = σ _z is shown.     

Patient risk in anesthesia: Probabilistic risk analysis and management improvements

In this paper, we present a pilot study in which we use probabilistic risk analysis (PRA) to assess patient risk in anesthesia and its human factor component. We then identify and evaluate the benefits of several risk reduction policies. We focus on healthy patients, in modern hospitals, and on cases where the anesthetist is a trained medical doctor. When an accident occurs for such patients, it is often because an error was made by the anesthesiologist, either triggering the event that initiated the accident sequence, or failing to take timely corrective measures. We present first a dynamic PRA model of anesthesia accidents. Our data include published results of the Australian Incident Monitoring Study as well as expert opinions. We link the probabilities of the different types of accidents to the state of the anesthesiologist characterized both in terms of alertness and competence. We consider different management factors that affect the state of the anesthesiologist, we identify several risk reduction policies, and we compute the corresponding risk reduction benefits based on the PRA model. We conclude that periodic recertification of all anesthesiologists, the use of anesthesia simulators in training, and closer supervision of residents could reduce substantially the patient risk.     

X-ray luminescence of Pb-containing microcrystals dispersed in the CsCl Matrix

The process of complexing in CsCl crystals in activating them with lead haloids PbX₂ (X=Cl, Br, I) (C_{PbX 2}=1 mole %) is investigated. The formation of CsPbCl₃ and Cs₄PbCl₆ microcrystals that are dispersed in the CsCl matrix is recorded. The luminescence-kinetic characteristics of the indicated microcrystals and single Pb²⁺v _c ⁻ centers are investigated. It is noted that the formation of the CsPbCl₃ and Cs₄PbCl₆ microcrystals is hindered as the radius of the anion of the lead haloid PbX₂ (X=Cl, Br, I) increases. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 67, No. 4, pp. 480–482, July–August, 2000.     

β-( N -Acylamino)vinylphosphonium Salts--Synthesis and Properties

A reaction of g -carbonyl phosphorus ylides with imidoyl halides gives hitherto unknown g -( N -acylamino)vinylphosphonium salts. The same product can be obtained using the N-monosubtituted amide/Ph 3 PBr 2 /Et 3 N system instead of imidoyl halide. The key step of the reaction probably involves an intramolecular [1,3] O-to-N migration of the vinyl group, converting the primary O -imidoylation product into g -( N -acylamino)vinylphosphonium salt.     

Synaptic behaviors and modeling of a metal oxide memristive device

Nanoscale memristive devices using tungsten oxide as the switching layer have been fabricated and characterized. The devices show the characteristics of a flux-controlled memristor such that the conductance change is governed by the history of the applied voltage signals, leading to synaptic behaviors including long-term potentiation and depression. The memristive behavior is attributed to the migration of oxygen vacancies upon bias which modulates the interplay between Schottky barrier emission and tunneling at the WO _X /electrode interface. A physical model incorporating ion drift and diffusion effects using an internal state variable representing the area of the conductive region has been proposed to explain the observed memristive behaviors. A SPICE model has been further developed that can be directly incorporated into existing circuit simulators. This type of device can be fabricated with low-temperature processes and has potential applications in synaptic computations and as analog circuit components.     

Acoustic,Viscometric, and Spectroscopic Studies of Dipropylene Glycol Monopropyl Ether with <Emphasis Type="Italic">n</Emphasis>-Alkanols at Temperatures of 288.15, 298.15, and 308.15 K

Speeds of sound have been measured in dipropylene glycol monopropyl ether mixtures with methanol, 1-propanol, 1-pentanol, and 1-heptanol as a function of composition at 288.15, 298.15, and 308.15 K and atmospheric pressure. Measurements of viscosity at 298.15 K and atmospheric pressure have also been made for the same mixtures over the whole composition range. The speeds of sound were combined with our previous densitity results to obtain the isentropic compressibility κ _S . The molar volumes were multiplied by the isentropic compressibilities to obtain estimates of K _S,m and its excess counterparts K_S,m^EK_{S,m}^{\mathrm{E}}. The K_S,m^EK_{S,m}^{\mathrm{E}} values are negative over the entire range of composition for all mixtures. Deviations in viscosity η from the mixing relation ∑x _i ln η _i and excess Gibbs energies of activation for viscous flow ΔG ^∗E have been derived for all of these systems. Also, from the speed of sound results, the apparent molar compressibilities [`(K)]_f,i⁰\overline{K}_{\phi ,i}^{0} of the components have been calculated at infinite dilution. The variations of these properties with the composition, temperature and the number of carbon atoms in the alcohol molecule are discussed in terms of molecular interactions. The experimental results have also been discussed on the basis of IR measurements.     

The Effect of Uniaxial Pressures on the Infrared Spectra of LiNH<Subscript>4</Subscript>SO<Subscript>4</Subscript> Crystals

The infrared reflection spectra of mechanically free and uniaxially compressed LiNH₄SO₄ crystals are studied for the first time in the spectral range of 800–1700 сm^–1 along three crystallophysical directions. The Kramers–Kronig dispersion relations are used to determine the dispersion and baric dependences of refractive index n and the real ε₁ and imaginary ε₂ parts of the dielectric constant and to calculate the frequencies of longitudinal ω_LO and transverse ω_ТO vibrations, decay constant γ, and oscillator strength f of mechanically free and compressed LiNH₄SO₄ crystals. The considerable changes observed in the main reflection bands are explained by the effect of uniaxial pressures on the NH₄ and SO₄ tetrahedra.