Algorithm based on the Thomson problem for determination of equilibrium structures of metal nanoclusters.

A new algorithm for the determination of equilibrium structures suitable for metal nanoclusters is proposed. The algorithm performs a stochastic search of the minima associated with the nuclear potential energy function restricted to a sphere (similar to the Thomson problem), in order to guess configurations of the nuclear positions. Subsequently, the guessed configurations are further optimized driven by the total energy function using the conventional gradient descent method. This methodology is equivalent to using the valence shell electron pair repulsion model in guessing initial configurations in the traditional molecular quantum chemistry. The framework is illustrated in several clusters of increasing complexity: Cu7, Cu9, and Cu11 as benchmark systems, and Cu38 and Ni9 as novel systems. New equilibrium structures for Cu9, Cu11, Cu38, and Ni9 are reported.

Phosphorene and phosphorene oxides as a toxic gas sensor materials: a theoretical study.

A systematic study of the adsorption of several harmful gases (CO2, NO, SO2, NH3y H2S) onto black phosphorene and three different black phosphorene oxides (BPO) is carried out through density functional theory calculations. In general, it is shown that BPOs are more suitable adsorbents than pure black phosphorene. Smaller values of adsorption energy correspond to CO2molecules, whilst those exhibiting larger ones are NH3, H2S, NO y SO2. It is found that SO2shows the greater difference in electronic charge transfer as well as the longer time of recovery among all species, being an electron acceptor molecule. Besides, it is revealed that physisorption induces changes of different order in the electronic, magnetic and optical responses of phosphorene systems involved. Greater changes in the electronic structure are produced in the case of NO adsorption. In that case, semiconductor nature and magnetization features of black phosphorene band structure become significantly modified. Moreover, a notorious effect of an externally applied electric field on the molecule adsorption onto BPOs has been detected. In accordance, adsorption energy changes with the applied electric field direction, in such a way that the higher value is favored through an upwards-directed orientation of NO y SO2adsorbates. Results presented could help to enhancing the understanding of BPOs as possible candidates for applications in gas sensing.

[Incidence of cough after desflurane and sevoflurane administration through a laryngeal mask: a controlled clinical trial]. / Comparación de la incidencia de tos entre desflurano y sevoflurano cuando se utiliza la máscara laríngea. Ensayo clínico controlado.

OBJECTIVE: To determine the incidence of cough with the administration of desflurane and sevoflurane through a laryngeal mask. METHODS: A double-blind controlled clinical trial in 90 patients who received general anesthesia for ear, nose and throat surgery outpatient. The experimental group (n = 45) inhaled desflurane and the control group (n = 45) inhaled sevoflurane. Rugloop simulation software was used to assure that each patient was under the effect of the induction agent (propofol). The Gasman program was used to ascertain that a minimum alveolar concentration of 1 had been achieved before the hypnotic effect of propofol was lost. Cough was evaluated on the Shahbaz scale during the 10 minutes following induction and at the end of the procedure. RESULTS: Cough in the first 10 minutes was recorded in 53.6% of patients in the desflurane group and in 2.4% in the sevoflurane group (P < .05). Between-group differences were also evident at the end of surgery (desflurane group, 24%; sevoflurane group, 9.7%; P< .05). CONCLUSION: The patients who inhaled desflurane through a laryngeal mask had a higher incidence of cough than those who inhaled sevoflurane. The mechanism by which cough is being triggered by desflurane should be studied to determine whether the effect is chemical or mechanical and whether it is acting in the larynx or in the distal portion of the lung.

Resistance of gastrointestinal nematodes to the most commonly used anthelmintics in sheep, cattle and horses in Spain.

The objective of this study was to evaluate the status of anthelmintic resistance (AR) in ruminants and horses in Spain. The efficacy of commonly used macrocyclic lactones (MLs) - ivermectin (IVM) and moxidectin (MOX) - was measured in sheep, cattle and horses. In addition, albendazole (ABZ) and levamisole (LEV) were evaluated in sheep and oxibendazole (OXI) and pyrantel (PYR) in horses. Efficacy was evaluated based on the difference between the arithmetic mean pre- and post-treatment faecal egg count (in cattle and horses), or compared to an untreated control group (in sheep). AR was present when the percentage reduction in egg count was <95% and the lower 95% confidence interval (CI) was <90%; if only one of these two criteria was met, the finding was recorded as suspected AR (SAR). In horses, AR-PYR and OXI was considered when the percentage reduction in egg count was ≤ 90% and the lower 95% CI was ≤ 80%. For each animal species, at least 10 study sites were selected. AR to at least one of the drugs was detected in all 10 sheep flocks; the main parasite identified after treatment was Teladorsagia circumcincta. Moreover, in 5 flocks multidrug resistance was identified, on 4 farms to drugs from different families, on one farm to both MOX and IVM and on another farm to all drugs tested. In cattle, the efficacy of both MOX and IVM was 100% on 4 and 3 farms, respectively, and therefore 60% of these farms were considered to have AR or SAR to both MLs. The most frequent parasite identified after treatment was Trichostrongylus spp., although Ostertagia ostertagi was also identified after treatment on one farm. In contrast to ruminants, the 4 drugs evaluated in horses were highly efficacious against strongyles, with efficacies for the MLs and OXI between 95 and 100% and between 94 and 100% for PYR, although 3 herds were SAR against PYR. In conclusion, AR to at least one of the commonly used drugs was identified on all sheep flocks investigated in the northwest of Spain. The occurrence of AR to MLs in cattle was higher than expected but consistent with what was observed in sheep. In horses, all currently used drugs were confirmed as effective against strongyles.

Scorpion envenoming in two regions of Colombia: clinical, epidemiological and therapeutic aspects.

To determine clinical and epidemiological features of scorpion stings in two departments of Colombia, a descriptive study was performed in the hospitals of 10 towns from Antioquia (2 256 071 inhabitants) and five from Tolima (630 424 inhabitants). One hundred and twenty-nine cases were admitted during one year, 51 in Antioquia, 78 in Tolima and 41 were children less than 15 years old. Most stings (70.5%) occurred inside the house; 27.9% were on the hands and 26.4% on the feet. The scorpion species involved were Tityus pachyurus (51), Centruroides gracilis (31), T. fuehrmanni (29), T. asthenes (7) and Chactas spp. (1). In 10 cases the scorpion involved was not identified. Systemic envenoming signs (e.g. vomiting, tachypnea) were significantly more frequent in children than in adults (P < 0.05). Four children had hypertension, but none developed pulmonary oedema. One 3-year-old girl, stung by T. asthenes, had acute oedematous pancreatitis. Ninety-eight patients had mild envenoming. Moderate (27 patients) and severe (four patients) envenoming was significantly more frequent in children than in adults (P = 0.003; relative risk = 2.97). A pepsin-digested anti-Centruroides spp. antivenom was administered to 19 of 31 patients presenting systemic envenoming signs. No adverse reactions to antivenom were observed.

[Changes in lipid availability in Venezuela, 1970-1992]. / Evolución de la disponibilidad lipídica en Venezuela 1970-1992.

The authors carry out a research focused on the quantification and analysis of the main changes in feeding and nutrition in Venezuela between 1970 and 1992. Such research started with the review and adjustment of the Food Balance Sheets (Hojas de Balance de Alimentos) elaborated by the Instituto Nacional de Nutrición (National Nutrition Institute) between 1970 and 1979 in order to homogenize them in a methodological way to make them similar to those elaborated by that institution and the Fundación Polar for the 1980-90 period. Estimates were made about the daily and per person availability of food for human consumption (DCH) for 1991 and 1992. This report, a partial product of that research, characterizes the evolution of the lipidic DCH in Venezuela for the 1970-1992 period. This period has been divided in seven stages of the evolution of the total energetic DCH, as this reflects well the course of the daily and per person Food Purchasing Power (PCA); there is a direct and strong functional relationship between these two variables. Along those stages the behaviour of the lipidic DCH is studied and we try to view possible relationships between the evolution of the Venezeluans economical situation and the absolute and relative variations observed in the level and the structure of the lipidic DCH. This structure is analyzed from several points of view: groups of food sources, origin, "visibility", and place of origin. One purpose is to determine also which food groups are mainly responsible for the venezuelan's external lipidic dependence. A general picture of the evolution of the DCH for saturated fatty acids and cholesterol is made, as well as of the variations experienced by the P/S and M/S relationships. It was found that the most dynamic elements, those that can explain a very high percentage of the variations observed in the level and the structure of the lipidic DCH were: the groups of foods of Visible Fats, Milk and dairy products, and Meats; vegetal lipids; vegetal-visible and animal-invisible lipidic fractions; imported lipids or lipids of food products which raw materials were imported (oily raw materials to make oils and edible solid fats, and raw materials to make food for poultry and hogs). The importance of the food groups Visible Fats, Milk and dairy products, and Meats, as sources or saturated fatty acids in the diet of the Venezuelans was made evident (89-91% of the respective total DCH), as well as the importance of the food groups Eggs, Meats, Fish and Seafood, and Milk and dairy products, as sources of cholesterol (82-89% of the available total). It was found that the lipid-originated calories account for less than 30% of the total energetic DCH; saturated fatty acids account for less than 10% of the available calories/person/day; the DCH for cholesterol did not reach the level of 300 mg/p/d; the P/S and M/S relationships remained close to 1. These last four facts are considered favorable for the health of the human being.

Estructuración y adecuación de un sistema centralizado de distribución de medicamentos por dosis unitaria, proyecto del hospital San Vicente de Paúl, de Caldas, Antioquia / Structuring and adjusting a centralized system for medicament distribution by unitary dose, a project of the hospital San Vicente de Paúl, in Caldas, Antioquia

Se acepta que el sistema centralizado de distribución de medicamentos por dosis unitaria (SCDMDU) contribuye a garantizar la efectividad terapéutica y administrativa y a disminuir los riesgos asociados con la utilización de estos insumos. Sin embargo, losanálisis de las inversiones económicas que se deben realizar para su estructuración limitan su presencia en nuestro medio. Buscando evidenciar las bondades del SCDMDU y sobre la base de que inicialmente no se requiere de una inversión económicaimportante, se diseñó un estudio longitudinal prospectivo de antes–después que posibilitara evaluar su impacto sobre los costos directos e indirectos en el servicio de pensionados de la ESE Hospital San Vicente de Paúl, de Caldas, Antioquia. El estudiose desarrolló durante 136 días (50 días en los que se midieron las variables de estudio en el sistema anterior, 36 días de capacitación y estructuración del SCDMDU y 50 días en los que se repitieron las mediciones iniciales). La información se procesó mediante EPI–INFO 6.03 y se analizó estadísticamente con el test de la t por parejas. Se obtuvo disminución en los costos por medicamentos de $1.306.221 (13,80 por cien ); en el valor de las solicitudes para reposición del inventario, de $500.940 (67,63 por cien ) y en las devoluciones, de $583.354 (39,46 por cien ). También se ve que este sistema facilita la detección y corrección oportuna de errores en los procesos asociados. Los resultados obtenidos evidencian que un SCDMDU contribuye a mejorar la calidad de la atención y a la optimización de los recursos, aspectos que son demandados por las condiciones creadas por la Ley 100/93 en Colombia