Formation of long, multicenter pi-[TCNE](2)(2-) dimers in solution: solvation and stability assessed through molecular dynamics simulations

Purely organic radical ions dimerize in solution at low temperature, forming long, multicenter bonds, despite the metastability of the isolated dimers. Here, we present the first computational study of these pi-dimers in solution, with explicit consideration of solvent molecules and finite temperature effects. By means of force-field and ab initio molecular dynamics and free energy simulations, the structure and stability of pi-[TCNE](2)(2-) (TCNE = tetracyanoethylene) dimers in dichloromethane have been evaluated. Although the dimers dissociate at room temperature, they are stable at 175 K and their structure is similar to the one in the solid state, with a cofacial arrangement of the radicals at an inter-planar separation of approximately 3.0 angstrom. The pi-[TCNE](2)(2-) dimers form dissociated ion pairs with the NBu4+ counterions, and their first solvation shell comprises approximately 20 CH2Cl2 molecules. Among them, the eight molecules distributed along the equatorial plane of the dimer play a key role in stabilizing the dimer through bridging C-H center dot center dot center dot N contacts. The calculated free energy of dimerization of TCNE center dot- in solution at 175 K is -5.5 kcal mol(-1). These results provide the first quantitative model describing the pairing of radical ions in solution, and demonstrate the key role of solvation forces on the dimerization process

Características morfológicas de avena blanca y raigrás en sistema silvopastoril y al pleno sol.

Resúmene

Memòria Digital de Catalunya

Conté la versió impresa sencera de l'obra (f. 1-16): Barcelona: Biblioteca de El Bombo, 1896Els f. 9 i 10 són dues versions quasi idèntiques del mateix fragment de textLocalització: Barcelona, Biblioteca de l'Ateneu Barcelonès, ms. 331Núm. [0?]65, a la coberta, i núm. 54, al f. 1Continuació de l'obra publicada amb aquest tít. (f. 9-20)Esmenes. Anotacions manuscrites d'altra mà posteriors relatives a la interpretació de la part musicalData aprox. deduïda a partir de la data d'edició de l'obraEscrit en un quadern per a ús de Juan AulíAcotacions entre parèntesisIncompletesa: f. previs al f. 13 retallatsText parcialment manuscrit i imprè

Survey and management of potato pests in Uganda

Potato (Solanum tuberosum L.) is an important food and income generating crop for its growers. The crop is also nutritionally rich in carbohydrates, vitamins (C and B), proteins, minerals (potassium) among other nutritional components. In Uganda, potato has been recognized as a crop with potential for nutrition security and income generation. Despite these benefits, average potato yield (4.8 t/ha) in Uganda is still comparatively lower than attainable global average yield (30 to 40 t/ha), owing to several biotic and abiotic production constraints. A study was conducted to establish the status of potato pests and diseases in north eastern and south western Uganda to include districts such as Mbale, Namisindwa, Kween, Kapchorwa and Kabale, Rubanda, Kisoro, respectively. The study was aimed at assessing the incidence and prevalence of key pests and diseases affecting potato in Uganda, with special emphasis on potato cyst nematode. Several pests and diseases including leaf miner flies, aphids, potato tuber moths, whiteflies, viruses, several nematode species, bacterial wilt (Ralstonia solanacaerum), and Fusarium spp. were observed to be affecting potato. Through the prospections conducted in this survey, the potato cyst nematode (Globodera rostochiensis) was identified in north eastern and south western areas of Uganda. Male farmers were more engaged in decision-making activities for potato production than their female counterparts in Eastern Uganda. An inclusive and multi institutional team was tasked to conduct this potato disease survey; this exercise was led by the International Institute of Tropical Agriculture (IITA) and the International Fertilizer Development Centre (IFDC-GIZ), with the special cooperation of the International Potato Centre (CIP), and the active engagement of the BugiZARDI-NARO and the District Production Office of the District Local Governments and Ministry of Agriculture, Animal Industry and Fisheries-Department of National Crop Certification Services

Facetas de Cerec

Al moderno sistema de las facetas de porcelana, para la restauración de las caras labiales de los dientes, se le añade la variación técnica consistente en su realización mediante el sistema CAD-CAM. Se describe la técnica y sus ventajas

π-Dimerization of Heptathienoacene Radical Cations

Oligothienoacenes, the fused-ring analog of pi-linked oligothiophenes, belong to the most promising candidates for organic electronic applications. This is in part due to their fully planar structure that avoids conformational disorder and allows for densely packed solid-state structures resulting in high charge carrier mobilities. In recent years, there has been a growing interest in the study of the pi-dimerization of conjugated radical cations with a dual purpose: (i) elucidation of the nature of the charge-transport phenomena in p-doped semiconducting polymers and (ii) development of supramolecular bonding ideas for applications in material science, such as actuators. However, the π-dimerization of planar conjugated radical cations in solution is scarce and usually encountered at low temperatures. In this work, we investigate the exceptional pi-dimerization capability showed by radical cations of a heptathienoacene alpha,beta-substituted with four n-decyl side groups (D4T7•+) by using a joint experimental and theoretical approach. D4T7 radical cations are found to exhibit an exceptional ability to form pi-dimer dications even at ambient temperature. Our results evidence the presence of two different transitory oxidized species formed during the course of the one-electron oxidation: (i) different conformations of the [D4T7•+]2 pi-dimer dications and (ii) the intermediate [D4T7]2•+ pi-dimer radical cations.[5] The nature and structure of these transitory species and ultimate pi-dimer dication are rigorously analyzed with the help of the DFT and TD-DFT calculations. Our study would provide valuable guidance for the further development of pi-dimer based supramolecular architectures.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Un nuevo enfoque en el estudio de las interferencias

El efecto de las interferencias sobre los cóndilos, se estudia con la aportación del cálculo de estructuras mediante una investigación interdisciplinar. Con este estudio se intenta profundizar en el estudio objetivo de los efectos de las interferencias para una comparación con los hallazgos clinicos

Epidemiologia de l'hepatitis B a Catalunya

L'hepatitis és una malaltia coneguda de fa molt temps. Sembla (que la primera referència al seu caràcter contagiós prové del segle vuitè després de Crist, quan en una carta a sant Bonifaci, arquebisbe de Magúncia, el papa Zacaries li recomana que els malalts d'icterícia estiguin separats per tat d'evitar el contagi dels altres. La literatura mèdica antiga conté nombrosos exemples d'epidèmies d'icterícia, que retrospectivament podem interpretar com hepatitis, bé que ens pot quedar el dubte que es tractés d'altres malalties epidèmiques que també fan curs amb icterícia, com és ara la febre groga i la leptospirosi

Ischemic aetiology, self-reported frailty, and gender with respect to cognitive impairment in chronic heart failure patients

Decisive information on the parameters involved in cognitive impairment in patients with chronic heart failure is as yet lacking. Our aim was to determine the functional and psychosocial variables related with cognitive impairment using the mini-mental-state examination (MMSE) with age-and education-corrected scores. A cohort study of chronic heart failure patients included in an integrated multidisciplinary hospital/primary care program. The MMSE (corrected for age and education in the Spanish population) was administered at enrolment in the program. Analyses were performed in 525 patients. Demographic and clinical variables were collected. Comprehensive assessment included depression (Yesavage), family function (family APGAR), social network (Duke), dependence (Barthel Index), frailty (Barber), and comorbidities. Univariate and multivariate logistic regression were performed to determine the predictors of cognitive impairment. Cognitive impairment affected 145 patients (27.6 %). Explanatory factors were gender (OR: 2.77 (1.75-4.39) p 3.5 (OR: 0.59 (0.35-0.99) p = 0.048), and beta-blocker treatment (OR: 0.36 (0.17 to 0.76, p = 0.007)). No association was found between cognitive impairment and social support or family function. The observed prevalence of cognitive impairment using MMSE corrected scores was 27.6 %. A global approach in the management of these patients is needed, especially focusing on women and patients with frailty, low albumin levels, and ischemic aetiology heart failure

Seven-year mortality in heart failure patients with undiagnosed diabetes : an observational study

Background: Patients with type 2 diabetes mellitus and heart failure have adverse clinical outcomes, but the characteristics and prognosis of those with undiagnosed diabetes in this setting has not been established. Methods: In total, 400 patients admitted consecutively with acute heart failure were grouped in three glycaemic categories: no diabetes, clinical diabetes (previously reported or with hypoglycaemic treatment) and undiagnosed diabetes. The latter was defined by the presence of at least two measurements of fasting plasma glycaemia ≥ 7 mmol/L before or after the acute episode.Group differences were tested by proportional hazards models in all-cause and cardiovascular mortality during a 7-year follow-up. Results: There were 188 (47%) patients without diabetes, 149 (37%) with clinical diabetes and 63 (16%) with undiagnosed diabetes. Patients with undiagnosed diabetes had a lower prevalence of hypertension, dyslipidaemia, peripheral vascular disease and previous myocardial infarction than those with clinical diabetes and similar to that of those without diabetes. The adjusted hazards ratios for 7-year total and cardiovascular mortality compared with the group of subjects without diabetes were 1.69 (95% CI: 1.17-2.46) and 2.45 (95% CI: 1.58-3.81) for those with undiagnosed diabetes, and 1.48 (95% CI: 1.10-1.99) and 2.01 (95% CI: 1.40-2.89) for those with clinical diabetes. Conclusions: Undiagnosed diabetes is common in patients requiring hospitalization for acute heart failure. Patients with undiagnosed diabetes, despite having a lower cardiovascular risk profile than those with clinical diabetes, show a similar increased mortality