ABSTRACT
Bond-valence parameters r0 and b, relating bond valence and bond length, are calculated for interactions between the ammonium ion and anions X = O, F, Cl. Searches in the Cambridge Structural Database (CSD) and in the Inorganic Crystal Structural Database (ICSD) were performed to obtain the lengths of NH4+...X contacts for ammonium ion environments in different structures. The procedure, which represents an extension of previous methods, allows certain environments to be rejected and enables the calculation of r0 and b from a reasonable range of interaction distances. Results are in very good agreement with the expected values on the basis of the assumed bond-valence model and their overall applicability to ammonium ion interactions is discussed.
Subject(s)
Models, Chemical , Quaternary Ammonium Compounds/chemistry , Anions/chemistry , Databases as Topic , Molecular StructureABSTRACT
OBJECTIVE: To discover the social, economic and cultural characteristics of the HIV+ population within our health area and any consequent implications for the spread of the disease. DESIGN: A descriptive study by means of a direct questionnaire. SETTING: The Macarena area in Sevilla. PATIENTS: 110 HIV+ patients. MEASUREMENTS AND MAIN RESULTS: A questionnaire, which included items concerning work situation, cultural and economic status, drug habits, sexual behaviour and social situation, was administered to 110 people. The determinant social profile of those patients studied was: male, PVDU, between 25 and 34, heterosexual, with multiple sexual partners, resident in the urban area, economically dependent on their parents with whom they live, and having a low education level. Homosexual patients had a higher education level. CONCLUSIONS: 1. The social conditions of marginal groups must be changed, in order to lessen drug consumption and so cut the epidemiological transmission chain. 2. High-risk behaviour, rather than high-risk groups, should be referred to, given that (albeit to a lesser degree) this infection can affect people at any social level, who engage in high-risk activities.
Subject(s)
HIV Seropositivity/epidemiology , Adolescent , Adult , Age Factors , Education , Female , Humans , Male , Middle Aged , Risk Factors , Sex Factors , Socioeconomic Factors , Sociology , Spain/epidemiology , Surveys and QuestionnairesABSTRACT
To determine the incidence of advanced arrhythmias and acute right bundle branch block during beside pulmonary artery catheterization, 119 critically ill patients undergoing 150 pulmonary artery catheterizations were prospectively studied using continuous electrocardiographic monitoring with permanent recordings. Ventricular arrhythmias other than isolated premature ventricular contractions, couplets or bigeminy occurred during 80 of the 150 catheterizations (53 percent). These included ventricular salvos (three to five consecutive premature ventricular contractions) in 30 percent, nonsustained ventricular tachycardia (five to 30 premature ventricular contractions) in 20 percent and sustained ventricular tachycardia (more than 30 consecutive premature ventricular contractions) in 3 percent. In two patients, ventricular fibrillation developed; in another three patients, lidocaine or precordial thump was required to terminate the episodes of ventricular tachycardia. The incidence of advanced ventricular arrhythmias was statistically correlated with either the presence of predisposing risk factors for ventricular ectopy (p less than 0.05) or prolonged catheterization time (p less than 0.01). A new right bundle branch block developed in seven patients (5 percent) and persisted for a mean of 9.5 hours.
