Analysis of the grafting process of PVP on a silicon surface by AFM and contact angle

Silicon wafers have been silylated with VTMS (vinyltrimethoxysilane) and hydrolyzed. Subsequently, PVP (polyvinyl pyrrolidone) was grafted onto the silylated surface by two different techniques: the grafting-through (GT) and the grafting-onto techniques (GO). The measurement of contact angles along with the topography analysis by atomic force microscopy (AFM) has allowed monitoring the different stages of the process and the temporal evolution of polymer grafting. The results have demonstrated the feasibility of both methods of grafting but have shown that the GT method gives a higher density of polymer-grafted chains. The AFM technique in adequate liquid environments has been proven to permit the surface density of chains to be distinguished by both methods and to estimate the length of the resulting PVP chains.

Lesión de Nora. Una entidad poco frecuente y de tratamiento discutible

La lesión de Nora se incluye en un conjunto de lesiones benignas caracterizadas por una proliferación anómala de tejido óseo y fibroso asociado a una reacción perióstica reactiva. Debido a su aspecto inicial, esta lesión puede ser confundida con una lesión maligna. Es frecuente realizar un diagnóstico incorrecto de esta entidad y, en consecuencia, un tratamiento improcedente. Se presenta el caso de una lesión de Nora que fue inicialmente diagnosticada de miositis osificante.

Rare-earth surface alloying: a new phase for GdAu2

Surface alloying is a powerful way of varying physical and chemical properties of metals, for a number of applications from catalysis to nuclear and green technologies. Surfaces offer many degrees of freedom, giving rise to new phases that do not have a bulk counterpart. However, the atomic characterization of distinct surface compounds is a major task, which demands powerful experimental and theoretical tools. Here we illustrate the process for the case of a GdAu2 surface phase of extraordinary crystallinity. The combined use of surface-sensitive techniques and state-of-the-art ab initio calculations disentangles its atomic and electronic properties. In particular, the stacking of the surface layers allows for gadolinium's natural ferromagnetic state, at variance with the bulk phase, where frustration leads to antiferromagnetic interlayer coupling.

Cytological characterization of sunflower by in situ hybridization using homologous rDNA sequences and a BAC clone containing highly represented repetitive retrotransposon-like sequences

In the present work we report new tools for the characterization of the complete chromosome complement of sunflower (Helianthus annuus L.), using a bacterial artificial chromosome (BAC) clone containing repetitive sequences with similarity to retrotransposons and a homologous rDNA sequence isolated from the sunflower genome as probes for FISH. The rDNA signal was found in 3 pairs of chromosomes, coinciding with the location of satellites. The BAC clone containing highly represented retroelements hybridized with all the chromosome complement in FISH, and used together with the rDNA probe allowed the discrimination of all chromosome pairs of sunflower. Their distinctive distribution pattern suggests that these probes could be useful for karyotype characterization and for chromosome identification. The karyotype could be subdivided into 3 clear-cut groups of 12 metacentric pairs, 1 submetacentric pair, and 4 subtelocentric pairs, thus resolving previously described karyotype controversies. The use of BAC clones containing single sequences of specific markers and (or) genes associated with important agricultural traits represents an important tool for future locus-specific identification and physical mapping.

Antimicrobial susceptibility of Helicobacter pylori and mechanisms of clarithromycin resistance in strains isolated from patients in Uruguay

The prevalence and mechanisms of antibiotic resistance of Helicobacter pylori have not yet been investigated in Uruguay. The objective of this study was to assess the susceptibility of H. pylori to the most frequently used antibiotics and to determine the mechanism of resistance to clarithromycin. Seventy-nine isolates were obtained from gastric biopsies of 50 adult patients during two periods, 2001 and 2006. The former group enrolled the general population (GP), the latter group Afro-descendant (AD) subjects. The minimum inhibitory concentrations of clarithromycin, amoxicillin, tetracycline, metronidazole, and levofloxacin were determined using the E-test technique. Amplification was achieved through PCR and nucleic acid sequencing to detect mutations in the site of action of clarithromycin in the rRNA gene 23S. No amoxicillin or tetracycline-resistant strains were found. Clarithromycin resistance was found in 12% of the patients overall: 19.4% resistance in AD patients and no resistance in the GP group. This difference was statistically significant. The highest resistance was seen with metronidazole (36%), present in similar proportions in the two groups: 36.8% (GP) and 35.5% (AD). One GP patient and one AD patient had levofloxacin-resistant strains. Sequencing analysis of gene 23S rRNA showed that only mutation in position 2143 was presented in all clarithromycin-resistant strains.

Influence of psychopathological changes on quality of life after laparoscopic fundoplication for the treatment of gastroesophageal reflux

There are references in medical literature to the influence of psychopathological changes and their negative impact on the results of laparoscopic fundoplication. The objective of this study is to analyze the influence of psychological changes, as assessed by the General Health Questionnaire-28 (GHQ-28), on patients undergoing surgery for gastroesophageal reflux. This is a prospective study in a series of 103 consecutive patients (62 males and 41 females with a mean age of 40 years) undergoing laparoscopic fundoplication. In addition to functional studies, patients completed the SF-36, Gastrointestinal Quality of Life Index, and GHQ-28 before surgery. Functional tests and questionnaires were repeated 6 months after surgery. Patients were also questioned about their degree of satisfaction. Postoperative results of patients with a normal GHQ-28 and patients showing psychopathological changes as defined by the GHQ-28 questionnaire before surgery were compared. Overall, all patients experienced an improvement in their quality of life. Forty-one patients showed a pathological result in the preoperative GHQ-28 questionnaire. No differences were found in functional results and degree of satisfaction with surgery between patients with normal and pathological results in the preoperative GHQ-28 questionnaire. However, patients with a pathological result in the preoperative GHQ-28 had poorer results in all domains of the postoperative Gastrointestinal Quality of Life Index and SF36 quality of life questionnaires as compared to patients with a normal preoperative GHQ-28 questionnaire. Patients with pathological results in the preoperative GHQ-28 had poorer results in terms of postoperative quality of life despite having normal postoperative physiological studies; this decreased quality of life did not have an impact on the degree of satisfaction with surgery performed. The GHQ-28 does not therefore appear to serve as a predictor of postoperative satisfaction.

Electronic states in faceted Au(111) studied with curved crystal surfaces

Vicinal Au(111) surfaces exhibit periodic faceting within a wide range of miscut angles. There, the system segregates two alternating phases with different step lattice constants d(w) and d(n). Using a curved crystal surface that allows a smooth variation of the surface orientation, we have studied, as a function of the miscut angle, the evolution of Au(111) faceted structures by scanning tunneling microscopy, and their electronic surface states by angle-resolved photoemission. We observe that surface bands reflect the two-phase character of the faceted system, i.e. we find d(w)- and d(n)-like states that evolve accordingly to the faceted structure. Using a photoemission calculation we prove that the apparently complex topology hides relatively simple physics, i.e. the same free-electron-like dispersion and repulsive step scattering that feature surface bands in stepped noble metal surfaces. On the grounds of such simulations, we discuss the possible interference of the electronic energy in the delicate free energy balance that determines the critical size of reconstructed (d(w)) and unreconstructed (d(n)) terraces during Au faceting.

[Treatment with venlafaxine extended release for climacteric women with depression or anxiety diagnosis. An open-label study]

INTRODUCTION

The objective of this observational study was to assess under real clinical practice conditions the effectiveness and safety of venlafaxine extended release in anxiety-depressed and hormone-related symptoms in climacteric women with anxiety or depressive disorders.

METHODOLOGY

Observational, prospective, open-label, multicenter, 24-week study, carried out in Spain. A sample of 45 outpatients, adult women between 45 and 55 years of age, diagnosed of depressive disorder, generalized anxiety disorder or social anxiety disorder were analyzed. Venlafaxine extended release was administered for 24 weeks at doses according to the investigator's clinical criteria.

RESULTS

Of the total of 45 patients who were included in the study, 43 (95.6%) completed it. The patients' age range was of 47 to 55 years old, median of 50 and mean of 50.82. The clinical condition evolution was assessed with the evaluation scales scores: Blatt-Kuppermann Menopausal Index, Hamilton Depression Rating Scale, Hamilton Anxiety Scale and Clinical Global Impression. During the 24-week period, a significant decrease in the different scales scores showed a clinical improvement.

CONCLUSIONS

The results achieved show that treatment with venlafaxine extended release significantly improved the clinical condition of climacteric patients with anxiety or depressive disorder. If these results are confirmed with placebo-controlled clinical trials, they will support the utility of Venlafaxine extended release in this kind of patients.

[Septic shock due to community-acquired complicated intra-abdominal infection treated with ertapenem: outcome in 25 cases]

OBJECTIVES

To assess the effectiveness of ertapenem in patients admitted to a surgical intensive care unit with septic shock due to community-acquired complicated intra-abdominal infection.

PATIENTS AND METHODS

Patients undergoing emergency surgery for community-acquired complicated intra-abdominal infection were enrolled prospectively. All patients were given intravenous ertapenem at a rate of 1 g/24 h and the guidelines of the Surviving Sepsis Campaign were applied. Outcome measures were duration of antibiotic therapy, mean length of stay in the surgical intensive care unit (ICU), antibiotic failure, and death while in the surgical ICU.

RESULTS

Twenty-five patients with a mean (SD) age of 74 (14) years were enrolled. The origin of infection was the colon in 56% of the cases; most patients (76%) had generalized peritonitis. The mean stay in the surgical ICU was 10 (7) days. The mean duration of antibiotic therapy was 5.8 (1.26) days. Antibiotic failure occurred in 12%. Mortality in the surgical ICU was 28%.

CONCLUSIONS

Our findings suggest that patients with community-acquired intra-abdominal infection and septic shock have a good chance of survival when treated according to the guidelines of the Surviving Sepsis Campaign. Ertapenem seems to give good results when used in this setting.

[Obtain best usage of meropenem dose in severe infections. Results of an observational multicenter study]

OBJECTIVE

To describe the effectiveness and tolerability of the dose adjustment of meropenem in empirical treatment of nosocomial infections in critically-ill patients admitted to intensive care medicine services.

METHODS

Prospective, observational and multicenter study in patients admitted to 17 intensive care medicine services with nosocomial infection, who were initially treated with meropenem, 1 g every 8 h, were eligible. The initial dose was adjusted to 0.5 g every 8 h if there were: a) a favorable clinical course, and b) microbiological isolation of meropenem-susceptible pathogens or absence of pathogens in cultures.

RESULTS

Ninety-two patients in whom meropenem doses were adjusted to 0.5 g every 8 h were included. Ventilator-associated pneumonia followed by bacteremia was the most frequently treated infections. Microbiological studies were positive in 53 patients, with a predominance of gram-positive bacteria (53.7%), especially methicillin-susceptible Staphylococcus aureus, followed by gram-negative bacteria (42.7 %). A total of 18 patients were not evaluable at the end of treatment. Sixty-seven (90.5 %) of the 74 evaluable patients had a favorable clinical course (54 patients cured and 13 improved). In 50 out of 53 microbiologically evaluable cases, eradication or apparent eradication of initial microorganisms was achieved. In 3 cases, the initial pathogen persisted: Acinetobacter baumannii (2 cases) and Pseudomonas aeruginosa (1 case). On three occasions, new pathogens developed during treatment: A. baumannii (2 cases) and methicillin-resistant S. aureus (1 case). Adverse events occurred in 3 patients (4%), none of which was considered severe, and withdrawal of meropenem was not necessary. A total of 25 (27.2 %) patients died, three of them in relation to the infectious process.

CONCLUSIONS

Dose adjustment of meropenem to 0.5 g every 8 h is a useful tool in the treatment of severe nosocomial infections in patients admitted to services of intensive care medicine except in cases in which causative pathogens are non-fermenting Gram-negative bacteria.

Structural and magnetic behaviour of soft magnetic Finemet-type ribbons

Different kinds of magnetic anisotropies have been induced during the nanocrystallization process of Co- and Ni-rich amorphous ferromagnetic (Finemet) ribbons by the application of a constant stress or an axial magnetic field during the annealing process. Magnetization measurements have evidenced the presence od macroscopic anisotropy in the treated samples. The main goal of this work has been, after a careful DSC study, the structural analysis of the treated ribbons using X-ray Diffraction and Atomic Force Microscopy (AFM), detecting substantial differences in the crystallization state and grain size of the samples depending on the thermal treatment that was carried out. Moreover, AFM measurements revealed in all the treated samples a strong nanocrystallisation of the surface without evidences of amorphous matrix, which contrast with XRD measurements that have shown a high content of amorphous phase in the bulk of the ribbons. Magneto-optical Kerr effect measurements have been performed with the aim to elucidate the complex magnetic behaviour that is expected for the surface of the ribbons, measuring surface hysteresis loops that showed much higher coercive field values than that obtained in the bulk material.