Genotoxic evaluation of a methanolic extract of Verbascum thapsus using micronucleus test in mouse bone marrow

Verbascum thapsus L. is a medicinal plant and has been used to treat numerous pulmonary diseases, asthma, inflammatory disease, spasmodic coughs and migraine headaches. Several studies have demonstrated that different extracts of V. thapsus present antimicrobial activity. Thus, the goal of this study was to evaluate the genotoxic and cytotoxic activities of a methanolic extract of Verbascum thapsus, using micronucleus test in mouse bone marrow. No toxicity in bone marrow was detected in the extract-treated groups. The methanolic extract of V. thapsus at doses of 100, 300 and 500 mg/kg, did not produce a significant increase in the frequency of MNPCE in bone marrow and neither altered the relationship PCE/NCE respect to negative control. These cytogenotoxic findings contribute the preclinical knowledge of methanolic extract of V. thapsus and provide security in its use as herbal medicine.     

Study of antiviral and virucidal activities of aqueous extract of Baccharis articulata against Herpes suis virus

Baccharis articulata is native of América and traditionally used for the treatment of digestive disorders and urinary infections. Cytotoxicity of aqueous extracts of B. articulata was investigated in Vero cells. As the maximal non cytotoxic concentration has been established, this concentration has been used to evaluate antiviral and virucidal activities against Herpes suis virus type 1, member of the same subfamily of Herpes simplex virus. Aqueous extracts of B. articulata exhibited more than 95% of virucidal activity. These findings support their potential application as a disinfectant or antiseptic with low toxicity and provide a valuable knowledge to ethnopharmacology properties of Baccharis articulata.     

Spectroscopic and electronic structure studies of copper(II) binding to His111 in the human prion protein fragment 106-115: evaluating the role of protons and methionine residues

The prion protein (PrP(C)) is implicated in the spongiform encephalopathies in mammals, and it is known to bind Cu(II) at the N-terminal region. The region around His111 has been proposed to be key for the conversion of normal PrP(C) to its infectious isoform PrP(Sc). The principal aim of this study is to understand the role of protons and methionine residues 109 and 112 in the coordination of Cu(II) to the peptide fragment 106-115 of human PrP, using different spectroscopic techniques (UV-vis absorption, circular dichroism, and electron paramagnetic resonance) in combination with detailed electronic structure calculations. Our study has identified a proton equilibrium with a pK(a) of 7.5 associated with the Cu(II)-PrP(106-115) complex, which is ascribed to the deprotonation of the Met109 amide group, and it converts the site from a 3NO to a 4N equatorial coordination mode. These findings have important implications as they imply that the coordination environment of this Cu binding site at physiological pH is a mixture of two species. This study also establishes that Met109 and Met112 do not participate as equatorial ligands for Cu, and that Met112 is not an essential ligand, while Met109 plays a more important role as a weak axial ligand, particularly for the 3NO coordination mode. A role for Met109 as a highly conserved residue that is important to regulate the protonation state and redox activity of this Cu binding site, which in turn would be important for the aggregation and amyloidogenic properties of the protein, is proposed.     

Solid phase extraction using nylon membranes with fluorescence detection as a fast and sensitive method for Amiloride and Furosemide determination in urine samples

A diuretic is a substance widely prohibited in competition sports, by the World Anti-Doping Agency (WADA). In this paper, a sensitive, rapid and convenient analytical solid phase extraction-fluorimetric method for the determination of furosemide (FUR) and amiloride hydrochloride (AMI) diuretics in human urine was developed. FUR and AMI exhibit overlapped fluorescent spectra and urine produces background fluorescence that precludes the direct determination of these diuretics by conventional fluorimetry. AMI was adsorbed using nylon membranes whereas; FUR was detected in aqueous solutions. The optimum analytical conditions for AMI and FUR assay were established. Excitation wavelengths of 365 nm and 237 nm and emission wavelengths of 406 and 415 nm were used for AMI and FUR, respectively. The calibration graphs are linear in the range of 3.7 × 10⁻⁴ to 0.8 μg mL^− 1 and 1.2 × 10^− 3 to 4.0 μg mL^− 1, for AMI and FUR, respectively, with a detection limit of 1.1 × 10^− 4 and 3.5 × 10^− 4 μg mL^− 1 (S/N = 3). These concentrations correspond well with the range of the drugs in urine. AMI and FUR were accurately quantified in doped urine samples and urine of subjects under medical treatment with diuretic. The results were validated by recovery test, being highly satisfactory.     

1,n-Diamines. Part 4: synthesis of 1-aryl-2-alkyl-1,4,5,6,7,8-hexahydro-1,3-diazocines

In this Letter we present the synthesis of hitherto unreported 1-aryl-2-alkyl-1,4,5,6,7,8-hexahydro-1,3-diazocines 1. Cyclic amidines 1 were synthesized by PPSE promoted ring closure of N-acyl-N′-arylpentamethylenediamines 2. The cyclodehydration reaction was performed under microwave irradiation in solvent-free conditions. Precursors 2 were prepared by selective functionalization of N-arylcadaverines 3.     

Membrane morphology modifications induced by hydroquinones

We synthesize and characterize alkylthiohydroquinones (ATHs) in order to investigate their interactions with lipid model membranes, POPE and POPC. We observe the formation of structures with different morphologies, or curvature of the lipid bilayer, depending on pH and increasing temperature. We attribute their formation to changes in the balance charge/polarity induced by the ATHs. Mixtures of ATHs with POPE at pH 4 form two cubic phases, P4(3)32 and Im3m, that reach a maximum lattice size at 40 °C while under basic conditions these phases only expand upon heating from room temperature. The cubic phases coexist with lamellar or hexagonal phases and are associated with inhomogeneous distribution of the ATH molecules over the lipid matrix. The zwitterionic POPC does not form cubic phases but instead shows lamellar structures with no clear influence of the 2,6-BATH.     

A new static calculation of the streamer region for long spark gaps

Different electrostatic approximations have been proposed to calculate the streamer region without going in deep details of the behavior of density of particles under the effect of high electric fields; this kind of approximations have been used in numerical calculations of long spark gaps and lightning attachment. The simplifications of the streamer region are achieved by considering it to be a geometrical region with a constant geometrical shape. Different geometrical shapes have been used, such as cones or several parallel filaments. Afterward, to simplify the procedures, the streamer region was approximated by two constants, one denoted K_Q, called the geometrical constant and in other cases K named as geometrical factor.However, when a voltage that varies with time is applied to an arrangement of electrodes (high voltage and grounded electrodes), the background electric field will change with time. Thus, if the background electric field is modified, the streamer zone could cover a larger or smaller area.With the aim of reducing the number of assumptions required in the calculation of long gap discharges, a new electrostatic model to calculate the streamer region is presented. This model considers a variable streamer zone that changes with the electric field variations. The three-dimensional region that fulfills the minimum electric field to sustain a streamer is identified for each time step, and the charge accumulated in that region is then calculated. The only parameter that is being used in the calculation is the minimum electric field necessary for the propagation of streamers.     

Relation between local temperature gradients and the direction of heat flow in quantum driven systems

We introduce thermometers to define the local temperature of an electronic system driven out-of-equilibrium by local ac fields. We discuss the behavior of the local temperature along the sample, showing that it exhibits spatial fluctuations following an oscillatory pattern. We show explicitly that the local temperature is the correct indicator for heat flow.     

<Emphasis Type="Italic">v</Emphasis>-Adic maximal extensions,spectral norms and absolute Galois groups

Let (K, v) be a perfect rank one valued field and let ([`(K<sub>v</sub>)],[`(v)]){(\overline{K_{v}},\overline{v})} be the canonical valued field obtained from (K, v) by the unique extension of the valuation [(v)\tilde]{\widetilde{v}} of K _v , the completion of K relative to v, to a fixed algebraic closure [`(K<sub>v</sub>)]{\overline{K_{v}}} of K <sub>v</sub> . Let [`(K)]{\overline{K}} be the algebraic closure of K in [`(K<sub>v</sub>)]{\overline {K_{v}}}. An algebraic extension L of K, L ì [`(K)]{L\subset\overline{K}}, is said to be a v-adic maximal extension, if [`(v)] | <sub>L</sub>{\overline{v}\mid_{L}} is the only extension of v to L and L is maximal with this property. In this paper we describe some basic properties of such extensions and we consider them in connection with the v-adic spectral norm on [`(K)]{\overline{K}} and with the absolute Galois groups Gal([`(K)]/K){(\overline{K}/K)} and Gal([`(K_v)] /K_v){(\overline{K_{v}} /K_{v})}. Some other auxiliary results are given, which may be useful for other purposes.     

Immersion enthalpy of benzene/cyclohexane and toluene/cyclohexane binary mixtures into modified activated carbons

Journal of Thermal Analysis and Calorimetry - The interaction between binary mixtures of benzene/cyclohexane and toluene/cyclohexane into three activated carbons with different physical and...