[en] Full text: Neutrons emitted from (alpha,n) reactions play an important role in several fields such as nuclear technology, nuclear astrophysics or underground (low background) physics. However, the current knowledge of the neutron yields and neutron energy spectra from (alpha,n) reactions is neither complete nor accurate; which has triggered a renewed interest in studying such reactions. In this context, several Spanish research groups has established the MANY Collaboration that aims at measuring (alpha,n) reactions by means of activation, neutron counting and time-of-flight at the CNA HISPANOS (Seville) and CMAM facilities (Madrid). The preliminary results of the recent experiment carried out at CNA HISPANOS for the study of the ²⁷Al(alpha,n) reaction by means of activation (using LaBr3 detectors) and by time-of-flight (using a pulsed beam and a Ej301 liquid scintillator module from the MONSTER array) will be presented. Then, the prospects for upgrades and future measurements will be discussed.

[en] A prospective work was made to highlight the value of the ultrasonido in the diagnosis of the affections of the digestive tract. In total 282 patients were explored constituted in 2 groups integrated by 82 and 200 sick persons, respectively. In the first group they were included patient to those that were detected a lesion of the digestive tract during an exploration ultrasonografica in a casual way. In the second group there are 100 patients that have previous diagnosis of lesion of the digestive tract and that they were studied later on with ultrasonido and 100 healthy to those that equally were carried out a study ultrasonografico. The results were: sensibility of 100%, specificity of 97%, value positive predictivos of 98,7%

[en] 

Purpose

Earthworm (Eisenia foetida) flour (EF) and hydrolyzed chicken feathers (HF) as sources of nitrogen and minerals for organic ethanol production were evaluated. In addition, EF and HF producing cost were determined throughout an energy analysis.

Methods

Saccharomyces cerevisiae and molasses, used as carbon source, were established in batch fermentations (32 °C, 24 h). Molasses and urea, were used as control. Biomass concentration (Log Cel ml⁻¹), reducing sugars, ethanol concentration, specific growth rate (μ), yeast viability (YV), product yield (Yp/s), and productivity, were measured, respectively.

Results

EF, HF and control substrate, maintained yeast viability from above 90%. Significant differences in biomass concentration occurred among substrates. Ethanol concentrations with EF, HF and control were of 55.20 gl⁻¹, 46.91 gl⁻¹, and 58. 12 gl⁻¹, respectively. Control substrate, exhibited the highest yield of product (0.50 gl⁻¹ of ethanol) at 24 h of fermentation.

Conclusions

The viability of yeast using HF and EF were above 90% and the fermentation rate and ethanol yield were at levels achieved with added urea and ammonium phosphate. EF and HF could be used as nitrogen sources for the organic production of ethanol replacing nitrogen conventional source.

[en] Promethium (Z = 61) is an exclusively radioactive element with short half-lives of up to 17 years. Consequently, Pm sample amounts that can be safely handled in laboratories are small and data on atomic transitions is scarce. Apart from the heavy actinides and transactinides, Pm is the last element where the first ionization potential (IP) has not been directly measured until now. Here we present the results from resonance ionization spectroscopy of ¹⁴⁷Pm (t_1/2 = 2.6 y) in a hot cavity laser ion source. More than 1000 new optical transitions were recorded in the spectral ranges from 415 - 470 nm and 800 - 910 nm using pulsed Ti:sapphire lasers. Although a straightforward analysis of Rydberg convergences was prevented by complex spectra for high excitation energies, the IP could be determined with a precision of better than 1 cm^-1 by measuring the electric field ionization threshold for several weakly bound states. Finally the hyperfine structure of two subsequent transitions in a newly developed RIS scheme was measured with experimental linewidths of ∼ 120 MHz as preparation for the extraction of nuclear structure parameters in on-line spectroscopy experiments on short-lived Pm isotopes.

[en] The knowledge of the neutron capture cross sections of s-process branching point isotopes represents a basic requirement for the understanding of star evolution. Since such branching point isotopes are by definition radioactive, the measurement of their cross sections from thermal to stellar energies becomes a challenging task. Considerable amounts of material have to be produced, representing a significant radioactive hazard. We report here on the production and separation of 3.5 mg ¹⁷¹Tm from 240 mg ¹⁷⁰Er₂O₃ and 72 μg ¹⁴⁷Pm from 100 mg ¹⁴⁶Nd₂O₃ irradiated at the ILL high flux reactor. Thin targets were prepared with high chemical and radioisotopic purity suitable for neutron capture measurements at nTOF CERN and the SARAF-LiLiT facility.

[en] In the study of the slow (s) process of nucleosynthesis branching nuclei become of particular interest. These nuclei have half-lives of the order of 1-100 years, and in the stellar environment their decay rate can compete with the neutron capture rate, which effectively leads to a split of the s-process path. Due to the dependence of the decay and the neutron capture rates on the the physical conditions -temperature and neutron density-of the nucleosynthesis environment, variations in these conditions lead to a change in the abundances of the immediately following nuclei. A very interesting branching point is the s-process only ²⁰⁴Tl, which decays to ²⁰⁴Pb. In this work we show how the capture cross section of ²⁰⁴Tl is a key nuclear input which, in addition to being crucial in fixing the ultimate ²⁰⁴Pb s-process abundance, makes the latter sensible to the temperature and neutron density of the stellar environment where the s-process takes place.

[en] In this article, the geographical location and availability of the most important crop residues generated in Mexico over the last 10 years (2008—2017) were determined. This study estimates the gross number of residues for the four most important cultivars in Mexico named conventional residues (CRs) such as corn, wheat, sorghum, and barley, and estimates were also made for regionally important crops identified as nonconventional residues (NCRs) such as coffee, sugarcane, and beans. The total and sustainable energy potentials (TEP and SEP) for agricultural residues were calculated, in similar way the butanol and electricity production potentials were also calculated if these residues were processed under a nonconventional biorefinery scheme; the calculated availability of crop residues was 59,059,666 t/year, thus demonstrating that Mexico could have great potential for bioenergy production. The estimated TEP was 1,787,241,249 PJ/year, and the SEP was 78,724,689 PJ/year. The production of butanol and its production cost were calculated for the main crop residues; the butanol volume ranged from 7348 to 161,610 t/day, and the volume of crops of regional importance ranged from 6461.9 to 151,389 t/day. The minimum butanol production cost was 2000 t/day of feedstock. The surplus electricity was determined for all crop residues.

[en] Cellulose nanocrystals (CNC) were obtained from Typha domingensis (an invasive macrophyte) collected from lagoons and wetlands in Altamira, Mexico. Cellulose extraction was carried out by a treatment with aqueous NaOH in a batch reactor followed by NaClO-bleaching and subsequent hydrolysis with sulfuric acid. The fibers were characterized by Fourier Transform Infrared (FTIR) spectroscopy, X-ray diffraction (XRD), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and atomic force microscopy (AFM). The crystallinity of the cellulose fibers isolated from Typha domingensis increased from 29 % (not treated fibers) to 73 % and the beginning of thermal degradation increased from 246 °C to 312 °C before and after the bleaching. The CNCs isolated from this plant show average values of 20 nm in diameter and 190 nm in length. Micrographs of the Typha domingensis fibers and the cellulose isolated therefrom as well as bleached cellulose indicate the removal of hemicellulose, lignin, and waxes from the fibers, which corroborates the XRD and FTIR results.

[en] A new experiment to measure the ²³⁸U(n,γ) cross-section has been carried out at the CERN n-TOF facility within the ANDES project. Two complementary detection systems have been used: two low neutron sensitivity C6D6 detectors and the Total Absorption Calorimeter (TAC) comprising 40 BaF₂ scintillators. High quality data has been obtained up to 10 keV with the TAC and up to a higher neutron energy unresolved region with the C₆D₆. All the steps in the measurements and the subsequent data analysis are dealt with in depth, aiming for overall 2-3% accuracy per detection system. (authors)

[en] Hydroxyethylcellulose (HEC) is a biodegradable, biocompatible polymer which is responsive to the temperature and pH values that can be reached by the human body. Polyacrylamide (PAAm) is a biocompatible and absorbent material which is highly used as a Drug Delivery System (DDS) due to its swelling capacity. In this work, a composite of HEC and PAAm was synthesized at a ratio of 25/75 wt% in order to evaluate its use as a transdermal DDS for acetaminophen. Drug release tests were performed in a phosphate buffer solution (PBS) at 35, 37, and 39 °C. The Korsmeyer-Peppas model was presented as a mathematical optimization problem and solved by Differential Evolution (DE) algorithm. Additionally, drug release data was modelled by Multigene Symbolic Regression (MSR) based on Genetic Programming (GP) algorithm. A drug release mathematical model was generated by MSR. The model is capable to reliably describe the kinetics of acetaminophen release from HEC/PAAm and to predict the concentrations of drug that is released in times beyond the experiment runtime. (paper)