72 research outputs found
The Phalacridae of the Maltese Islands (Coleoptera)
Ten species of Phalacridae from Malta were found during the present study, of which Olibrus particeps and Tinodemus polygramma represent new records for this territory. Earlier citations of Olibrus bimaculatus and O. liquidus were found to be incorrect and should refer to O. bicolor and O. castaneus respectively. Also the earlier citations of Phalacrus substriatus and P. fimetarius were found to be based on misidentifications and should refer to P. corruscus.peer-reviewe
Spectral analysis of the beat-to-beat variability of arterial compliance
Arterial compliance is an important parameter influencing ventricular-arterial coupling, depending on structural and functional mechanics of arteries. In this study, the spontaneous beat-to-beat variability of arterial compliance was investigated in time and frequency domains in thirty-nine young and healthy subjects monitored in the supine resting state and during head-up tilt. Spectral decomposition was applied to retrieve the spectral content of the time series associated to low (LF) and high frequency (HF) oscillatory components. Our results highlight: (i) a decrease of arterial compliance with tilt, in agreement with previous studies; (ii) an increase of the LF power content concurrent with a decrease of the HF power, potentially reflecting changes in vasomotor tone, blood pressure and heart rate variability associated with higher sympathetic activity and vagal withdrawal occurring with tilt
Correction of RTâqPCR data for genomic DNA-derived signals with ValidPrime
Genomic DNA (gDNA) contamination is an inherent problem during RNA purification that can lead to non-specific amplification and aberrant results in reverse transcription quantitative PCR (RTâqPCR). Currently, there is no alternative to RT(â) controls to evaluate the impact of the gDNA background on RTâPCR data. We propose a novel method (ValidPrime) that is more accurate than traditional RT(â) controls to test qPCR assays with respect to their sensitivity toward gDNA. ValidPrime measures the gDNA contribution using an optimized gDNA-specific ValidPrime assay (VPA) and gDNA reference sample(s). The VPA, targeting a non-transcribed locus, is used to measure the gDNA contents in RT(+) samples and the gDNA reference is used to normalize for GOI-specific differences in gDNA sensitivity. We demonstrate that the RNA-derived component of the signal can be accurately estimated and deduced from the total signal. ValidPrime corrects with high precision for both exogenous (spiked) and endogenous gDNA, contributing âŒ60% of the total signal, whereas substantially reducing the number of required qPCR control reactions. In conclusion, ValidPrime offers a cost-efficient alternative to RT(â) controls and accurately corrects for signals derived from gDNA in RTâqPCR
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Intramolecular photo-induced electron transfer in a rigid anthracene-N, N-dimethylaniline system
2-(N,N-Dimethylamino)-5, 14-ethanopentacene (1) was synthesized and spectroscopic behaviors investigated. Results suggest that 1 undergoes photoinduced electron transfer (PET) in solvents more polar than saturated hydrocarbons. The resulting charge-transfer (CT) state undergoes CT fluorescence efficiently in solvents of low dielectric constants. Fluorescence excitation studies of the CT emission reveal the existence of an EDA interaction in the ground state. The implications of these results are discussed
Collision times in pi-pi and pi-K scattering and spectroscopy of meson resonances
Using the concept of collision time (time delay) introduced by Eisenbud and
Wigner and its connection to on-shell intermediate unstable states, we study
mesonic resonances in pi-pi and pi-K scattering. The time-delay method proves
its usefulness by revealing the spectrum of the well-known rho- and K*-mesons
and by supporting some speculations on rho-mesons in the 1200 MeV region. We
use this method further to shed some light on more speculative meson
resonances, among others the enigmatic scalars. We confirm the existence of
chiralons below 1 GeV in the unflavoured and strange meson sector.Comment: 22 pages LaTex, 8 figure
Controlled ultraviolet (UV) photoinitiated fabrication of monolithic porous layer open tubular (monoPLOT) capillary columns for chromatographic applications
An automated column fabrication technique that is based on a ultraviolet (UV) light-emitting diode (LED) array oven, and provides precisely controlled "in-capillary" ultraviolet (UV) initiated polymerization at 365 nm, is presented for the production of open tubular monolithic porous polymer layer capillary (monoPLOT) columns of varying length, inner diameter (ID), and porous layer thickness. The developed approach allows the preparation of columns of varying length, because of an automated capillary delivery approach, with precisely controlled and uniform layer thickness and monolith morphology, from controlled UV power and exposure time. The relationships between direct exposure times, intensity, and layer thickness were determined, as were the effects of capillary delivery rate (indirect exposure rate), and multiple exposures on the layer thickness and axial distribution. Layer thickness measurements were taken by scanning electron microscopy (SEM), with the longitudinal homogeneity of the stationary phase confirmed using scanning capacitively coupled contactless conductivity detection (sC(4)D). The new automated UV polymerization technique presented in this work allows the fabrication of monoPLOT columns with a very high column-to-column production reproducibility, displaying a longitudinal phase thickness variation within ±0.8% RSD (relative standard deviation)
Kinetic analysis of Al3Ti intermetallic powder after mechanical treatment in hydrogen
We present results of mechanochemical processing experiments performed on intermetallic powder, Al3Ti milled under hydrogen and helium atmospheres using a magnetically controlled Uniball device. Milling products were investigated by X-ray diffractometry (XRD), transmission electron microscopy (TEM) and advanced differential thermal analysis (DTA and DSC). Milling in both H2 and in He resulted in breakdown of the intermetallic structure and, after extended milling, formation of nanostructural products comprising, predominately, a solid solution of Ti in fcc Al, with some possible additional Al1+xTi1âx (x = 0.3) phase. Detailed kinetic analysis was preformed on the Al3Ti sample milled for 6 days in hydrogen. Under isothermal annealing, the crystallization of the Al5Ti2 was found to follow the JMA kinetics, with constant activation energy Eâ and Avrami exponent n decreasing from 2.5 to 1.5
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