Dark energy degeneracies in the background dynamics

We discuss degeneracies between dark energy and cosmic parameters using a fully non-perturbative and non-parametric approach. This allows us to examine the knock-on bias induced in the reconstructed dark energy equation of state, w(z), if there is a bias in the cosmic curvature or dark matter content. Assuming perfect Hubble, distance and volume measurements, we show that for z > 1, the bias in w(z) is up to two orders of magnitude larger than the corresponding errors in Ω _k or Ω _m .     

Probing the order-to-chaos region in superdeformed 151Tb and 196Pb nuclei with continuum gamma transitions

The gamma decay associated with the warm rotation of the superdeformed nuclei 151Tb and 196Pb has been measured with the EUROBALL IV array. Several independent quantities provide a stringent test of the population and decay dynamics in the superdeformed well. A Monte Carlo simulation of the gamma decay based on microscopic calculations gives remarkable agreement with the data only assuming a large enhancement of the B(E1) strength for 1-2 MeV gamma rays, which may be related to the evidence for octupole vibrations in both mass regions.     

Absence of superconductivity down to 80 mK in graphite intercalated BaC6

Following recent theoretical and experimental investigations of superconductivity in the graphite intercalated compounds CaC₆ and SrC₆, we report on a very low temperature magnetisation study on BaC₆ down to 80 mK. The data show no trace of superconductivity even at fields as low as 0.7 Oe. Using a McMillan parametrisation of the BCS parameters, we conclude that the Coulomb pseudopotential is expected to be as large as 0.19 in both BaC₆ and SrC₆, i.e. 40% larger than in CaC₆. As an alternative scenario, we argue that extrinsic effects such as intercalant disorder may depress superconductivity in both BaC₆ and SrC₆, as in the case of CaC₆.     

Changes in mouse Leydig cells ultrastructure and testosterone secretion after diethylcarbamazine administration

Diethylcarbamazine (DEC) has been proven to be highly effective against lymphatic filariasis, although its effect on vertebrate cells remains uncertain. Mice Leydig cells after treatment with 200mg/kg of DEC for 12 days showed numerous lipid droplets, degenerated mitochondria, residual bodies and several giant whorl-like smooth endoplasmic reticulum, some of them encircling large lipids droplets. Treatment with lower dosages showed similar alterations on Leydig cells and the morphological effects decreased directly proportional to the drug concentration. Serum testosterone levels were significantly lower only in 200 mg/kg DEC-treated group when compared to the controls. However, no significant changes were observed in the pregnancy rates and offspring number of DEC-treated male-mated female mice in any doses studied. The results obtained in the present study are consistent with the hypothesis that DEC has some effects on mice Leydig cells, although they were not sufficient enough to interfere with the rodent fertility.     

Ultrasonic properties of water/sorbitol solutions

Ultrasonic longitudinal velocity and attenuation were measured for aqueous solutions of sorbitol at approximately 5 MHz. For pure sorbitol, the ultrasonic velocity reached 3200 m s⁻¹, consequently leading to a high acoustical impedance (around 5 × 10⁶ Rayleigh) and good matching between the ultrasonic transducers and material samples.     

1,4-Dihydropyridine/BF3OEt2 for the reduction of imines: Influences of the amount of added BF3OEt2 and the substitution at N-1 and C-4 of the dihydropyridine ring

We have evaluated four 1,4-dihydropyridines (DHPs 1a, 1b, 1c and 1d) as reducing agents, which presented free (hydrogenated) or phenyl-substituted N-1 and C-4 positions of the DHP ring. Reactions combining each of the DHP and different amounts of BF₃OEt₂ were evaluated for the reduction of imine 2a (N-benzylideneaniline). DHP simultaneously substituted at N-1 and C-4 (1a), and DHP substituted at C-4 (1b) gave lower yields for reduction of 2a in comparison with DHPs 1c and 1d (both unsubstituted at the C-4 position). By evaluating the amount of added BF₃OEt₂ to the reaction mixture, we have found that DHP 1c (substituted at N-1) provided its best yield for amine 3a (82%) when associated with stoichiometric amounts BF₃OEt₂, while DHP 1d (N-1- and C-4-unsubstituted derivative) was more effective (90% yield) with catalytic quantities of the Lewis acid. The reaction system using DHP 1c under stoichiometric BF₃OEt₂ could also be successfully applied with additional imine examples and under reductive amination conditions.     

Synthesis of novel 8-(het)aryl-6H-pyrano[4′,3′:4,5]thieno[3,2-b]pyridines by 6-endo-dig cyclization of Sonogashira products and halolactonizations with Cu salts/NXS. Preliminary antitumor evaluation

Novel 8-(het)aryl-6H-pyrano[4′,3′:4,5]thieno[3,2-b]pyridines were prepared in good to high yields by a tandem one-pot procedure of Sonogashira coupling and 6-endo-dig lactonization from 3-bromothieno[3,2-b]pyridine-2-carboxylic acid and (het)arylalkynes. Sonogashira coupling products were also prepared from the corresponding methyl ester giving in the same reaction the corresponding 6-endo-dig compounds as minor products. The Sonogashira phenyl ester product gave cyclization with electrophiles only in low to moderate yields. Nevertheless, halolactonizations using Cu(I) or (II) salts/N-halosuccinimides (NXS) from either the phenyl ester or the carboxylic acid derivatives occurred in good to high yields. The growth inhibition potential of the compounds was evaluated using human tumor cell lines, HCT-15 (colorectal adenocarcinoma) and NCI-H460 (non-small cell lung cancer) and studies of apoptosis induction were performed for the three most promising compounds in HCT-15?cells. Two of them caused almost 40% of cell death by apoptosis when tested at their 1.5?×?GI₅₀ concentrations. The tricyclic lactone with a F atom in the meta position showed to be the most promising one.     

Time-resolved diffusing wave spectroscopy applied to dynamic heterogeneity imaging

We report what is to our knowledge the first observation of a time-resolved diffusing wave spectroscopy (DWS) signal recorded by transillumination through a thick turbid medium: the DWS signal is measured for a fixed photon transit time, which opens the possibility of improving the spatial resolution. This technique could find biomedical applications, especially in mammography.     

Simultaneous Voltammetric Determination of Benzene,Toluene and Xylenes (BTX) in Water Using a Cathodically Pre‐treated Boron‐doped Diamond Electrode

An electrochemical method for the simultaneous determination of benzene, toluene and xylenes (BTX) in water was developed using square‐wave voltammetry (SWV). The determination of BTX was carried out using a cathodically pre‐treated boron‐doped diamond electrode (BDD) using 0.1 mol L^?1 H₂SO₄ as supporting electrolyte. In the SWV measurements using the BDD, the oxidation peak potentials of the total xylenes‐toluene and toluene‐benzene couples, present in ternary mixtures, display separations of about 100 and 200 mV, respectively. The attained detection limits for the simultaneous determination of benzene, toluene and total xylenes were 3.0×10^?7, 8.0×10^?7 and 9.1×10^?7 mol L^?1, respectively. The recovery values taken in ternary mixtures of benzene, toluene and total xylenes in aqueous solutions are 98.9 %, 99.2 % and 99.4 %, respectively.     

Zur Bildung der Benzimidazolderivate aus o-Phenylendiamin und Hydroxy-dicarbonsäuren

Zusammenfassung Bei der Kondensation der Weinsäure und Schleimsäure mit o-Phenylendiamin kann man neben den bekannten Bisbenzimidazolylderivaten auch die bisher nicht beschriebenen Monobenzimidazolylderivate in guter Ausbeute bekommen.