Effect of the ionic surfactant concentration on the stabilization/destabilization of polystyrene colloidal particles.

One of the most interesting properties of the surfactants is that they are able to alter the stability of colloidal dispersions. Despite its great industrial relevance, only a few works analyze the colloidal stability of these systems at high surfactant concentrations (well above the critical micelle concentration (CMC)). In the present work, the colloidal stability of polystyrene particles is studied under a wide range of ionic surfactant concentrations.

Electrokinetic behavior and colloidal stability of polystyrene latex coated with ionic surfactants.

This work is focused on analyzing the electrokinetic behavior and colloidal stability of latex dispersions having different amounts of adsorbed ionic surfactants. The effects of the surface charge sign and value, and the type of ionic surfactant were examined. The analysis of the electrophoretic mobility (mu(e)) versus the electrolyte concentration up to really high amounts of salt, much higher than in usual studies, supports the colloidal stability results.

Dental caries among the pre-Hispanic population from Gran Canaria.

The island of Gran Canaria was inhabited in pre-Hispanic times by people of North African origin who arrived on the island towards the second half of the first millennium BC. In previous studies, we reported that there are some differences between the coastal inhabitants from Gran Canaria, mainly buried in tumuli, and those from the central mountains, mainly buried in caves. For example, the prevalence of auricular exostoses is higher among the population interred in coastal tumuli when compared with the inland population.

Psychosocial adaptation in relatives of critically injured patients admitted to an intensive care unit.

The aim of this study is to analyze how the length of time a patient spends in an Intensive Care Unit (ICU) affects close relatives, with regard to specific clinical variables of personality, family relationships and fear of death. The study group consisted of 57 relatives of seriously ill patients admitted to the ICU of "Virgen del Rocío" Rehabilitation and Trauma Hospital (Seville, Spain). The instruments applied were: a psychosocial questionnaire, clinical analysis questionnaire, family environment scale and fear of death scale.

Psychological adaptation of liver transplant recipients.

We analyzed the influence of two variables (place of hospitalization of the patients and the mental health of relatives) on symptoms of anxiety and depression in liver transplant patients. The subject groups were made up of 48 liver transplant recipients (mean age 51.15; SD = 8.

Psychologic stages in renal transplant.

Health workers must be aware of the psychologic stages experienced by their patients. We analyzed the influence of the posttransplant time on thoughts (depressive and anxious) and body image perception in renal transplant recipients. The sample consisted of 59 adult patients (mean age +/- SD: 45.

[A method for ascertaining the seasonal pattern of hospital emergency department visits].

A suitable method is set forth in this study for isolating and describing high frequency seasonal variations which may occur in some sets of time series in the healthcare setting. If the simultaneous presence of seasonal variations within a day, a week and a year is not taken into account, the estimates of seasonal behaviours may be noticeably distorted and the decisions made by those in charge of managing healthcare services based thereupon might be erroneous. The proposed procedure, based upon taking simultaneous periodic changes jointly into consideration is applied to an hourly series of patients visiting an hospital emergency room in Tenerife.

High-frequency health data and spline functions.

Seasonal variations are highly relevant for health service organization. In general, short run movements of medical magnitudes are important features for managers in this field to make adequate decisions. Thus, the analysis of the seasonal pattern in high-frequency health data is an appealing task.

Adsorption of different amphiphilic molecules onto polystyrene latices.

In order to know the influence of the surface characteristics and the chain properties on the adsorption of amphiphilic molecules onto polystyrene latex, a set of experiments to study the adsorption of ionic surfactants, nonionic surfactants and an amphiphilic synthetic peptide on different latex dispersions was performed. The adsorbed amount versus the equilibrium surfactant concentration was determined. The main adsorption mechanism was the hydrophobic attraction between the nonpolar tail of the molecule and the hydrophobic regions of the latex surface.

Adsorbed and spread beta-casein monolayers at oil-water interfaces.

A previous study (Langmuir 2003, 19, 8436) used a Langmuir type pendant drop film balance to form beta-casein monolayers at the air-water interface. The present paper reports the application of that technique to the formation of protein monolayers at liquid interfaces. This technique allows a direct comparison between spread and adsorbed beta-casein interfacial behaviors that is presented in terms of their pi-A isotherms and static elasticity moduli.

[Symptoms of anxiety and depression in liver-transplant patients].

Introduction: We analyzed the influence of two variables (place of hospitalization of the patients and mental health of relatives) on anxiety and depression symptoms in liver-transplant patients.

Methods: The subject groups were made up of 48 liver-transplant patients and 48 close relatives. The tests applied were a psychosocial questionnaire and the following instruments: The Hospital Anxiety and Depression Scale, The Leeds Scales for the Self-Assessment of Anxiety and Depression and Social Support Scale.

[Assessment of Machiavellian intelligence in antisocial disorder with the MACH-IV Scale].

Introduction: The objective is to evaluate the presence of Machiavellian intelligence with the MACH-IV Scale in antisocial patients versus community controls.

Material And Methods: Categorical diagnosis and dimensional evaluation program according to IPDE were obtained from 26 controls from the community and 40 patients from a methadone program. Both groups were evaluated on cooperation with TCI and on Machiavellian intelligence with MACH-IV.

[Evolution of antipsychotic drug consumption in the autonomous community of Castile and Leon, Spain (1990-2001)].

Background: Over the past ten years, new drugs and new approaches to treatment have been implemented making it possible to assume changes in the use of antipsychotic drugs in our environment. This study is aimed at characterizing the pattern of use of antipsychotic drugs in Castile and Leon throughout the 1990-2001 period as well as ascertaining the bearing which the marketing of new antipsychotic drugs may have had on the pattern of consumption of these drugs.

Methods: The drug consumption data was obtained from the Ministry of Health and Consumer Affairs' consumption database ECOM (Especialidades Consumo de Medicamentos).

[Antisocial personality disorder evaluation with the prisoner's dilemma].

Introduction: The aim of this study is to evaluate cooperation problems in antisocial disorder with the prisoner's dilemma game, which, in mathematical game theory, is the paradigm of the <> games (mutual benefit from cooperation).

Methods: We have designed a computer version of the prisoner's dilemma (CDT-BD) that confronts the patient to a simulation of a reciprocal exchange situation. IPDE provided us a categorical and dimensional evaluation of 26 controls from the community and 40 methadone patients.

Effect of firmness of mattress on chronic non-specific low-back pain: randomised, double-blind, controlled, multicentre trial.

Background: A firm mattress is commonly believed to be beneficial for low-back pain, although evidence supporting this recommendation is lacking. We assessed the effect of different firmnesses of mattresses on the clinical course of patients with chronic non-specific low-back pain.

Methods: In a randomised, double-blind, controlled, multicentre trial, we assessed 313 adults who had chronic non-specific low-back pain, but no referred pain, who complained of backache while lying in bed and on rising.

Identification of species of Brucella using Fourier transform infrared spectroscopy.

Fourier transform infrared spectroscopy (FTIR) is a technique that has been used over the years in chemical analysis for the identification of substances and is one that may be applied to the characterisation of microorganisms. The marked tendency of Brucella towards variation in the smooth rough phase, together with the laboriousness and risk involved in the methods used in their identification, make their classification difficult. We studied the type strains of the different species and biovars of Brucella and 11 isolates of human origin of Brucella melitensis, six corresponding to biovar 1, one to biovar 2 and five to biovar 3.

[Intestinal tuberculosis. A diagnostic challenge].

Tuberculosis (TB) is a common disease in Spain, whose incidence has increased due to AIDS, immunotherapy and immigration. Intestinal disease is rare and can be difficult to diagnose because its symptoms and laboratory results are nonspecific. In addition, endoscopic lesions resemble those of other diseases such as Crohns disease (CD).

[Laryngeal and hypopharyngeal liposarcoma. Report of a case and literature review].

Liposarcoma is the second sarcoma of soft tissues more frequent in adult-age. Its localisation in head and neck is odd. The majority of liposarcoma, of this sitting, take its origin from soft tissues of the neck, being unusual primary liposarcoma from larynx and hypolarynx.

[Peri-testicular fibromatosis (testicular fibrous pseudotumor)].

Objective: We report a case of fibromatous periorchitis, a rare entity that may have differential diagnosis problems with other lesions.

Methods: Our patient underwent a surgical procedure with resection of the tunica vaginalis testis after intraoperative histological evaluation.

Results: Findings observed in both intraoperative biopsy and specimen histopathological study were key for diagnosis.

Sequential Adsorption of Triton X-100 and Sodium Dodecyl Sulfate onto Positively and Negatively Charged Polystyrene Latexes.

Individual and sequential adsorption of the anionic surfactant sodium dodecyl sulfate (SDS) and the nonionic surfactant Triton X-100 on cationic and anionic polystyrene latexes has been examined. Both latex samples, although charged differently (-16.2 and +11.

An Enthalpic Analysis on the Aggregation of Colloidal Particles Studied by Microcalorimetry.

There are different theories concerning the stability of colloidal suspensions. Most of them arise from the well-known DLVO theory which relates colloidal stability to intermolecular forces between particles. Experimental corroboration of these theories has been obtained mainly by using different optical techniques that analyze changes in the optical properties of the solution while particles aggregate.