Solvent-exchange process in MOF ultrathin films and its effect on CO2 and methanol adsorption.

Metal-organic framework (MOF) activation is crucial for the use of MOFs in several applications and solvent-exchange process is a necessary step in many activation methods. In this contribution, we have explored in situ MOF monolayer film formation at the air-water interface. Nanoparticles (NPs) of the Al trimesate MIL-96(Al) retain chloroform into their micropores, which considerably diminishes the CO2 adsorption capacity of MOF films. However, a solvent-exchange process between chloroform and water increases CO2 film adsorption capacity by 30%. Total Reflection X-Ray Fluorescence (TRXF) allows studying the kinetics of this process at the air-water interface, that strongly depends on the NP size. The conclusions derived from in situ studies allow optimizing the ex situ activation procedure of MIL-96(Al) films deposited onto quartz crystal microbalance (QCM) substrates in order to maximize CO2 and methanol adsorption.

Fabrication of ultrathin MIL-96(Al) films and study of CO2 adsorption/desorption processes using quartz crystal microbalance.

This contribution reports the fabrication and characterization of ultrathin films of nanoparticles of the water stable microporous Al tricarboxylate metal organic framework MIL-96(Al). The preparation of MOF dispersions in chloroform has been optimized to obtain dense monolayer films of good quality, without nanoparticle agglomeration, at the air-water interface that can be deposited onto solid substrates of different nature without any previous substrate functionalization. The MOF studied shows great interest for CO2 capture because it presents Al3+ Lewis centers and hydroxyl groups that strongly interact with CO2 molecules. A comparative CO2 adsorption study on drop-cast, Langmuir-Blodgett (LB) and Langmuir-Schaefer (LS) films using a Quartz Crystal Microbalance-based setup (QCM) has revealed that the CO2 uptake depends strongly on the film fabrication procedure and the storage conditions. Noteworthy the CO2 adsorption capacity of LB films is increased by 30% using a simple and green treatment (immersion of the film into water during 12 h just after film preparation). Finally, the stability of LB MOF monolayers upon several CO2 adsorption/desorption cycles has been demonstrated, showing that CO2 can be easily desorbed from the films at 303 K by flowing an inert gas (He). These results show that MOF LB monolayers can be of great interest for the development of MOF-based devices that require the use of very small MOF quantities, especially gas sensors.

Propolis nasal spray effectively improves recovery from infectious acute rhinitis and common cold symptoms in children: a pilot study.

Currently, treatment for acute rhinitis (AR) is symptomatic but no clear agreement exists to control its development. Propolis extract may appear as a promising natural treatment for AR, but its beneficial effects have not yet been fully tested. Forty children suffering from AR and common cold symptoms aged between 2-12 years were enrolled in a prospective epidemiological multicentre study. A 7-day treatment with propolis nasal spray (3 times/day) was applied and a comparison of symptomatology, subjective global improvement and quality of life (QoL) between baseline (day 1) and final (day 7) visits were performed. The main goal was to evaluate the changes in symptom intensity using the Jackson’s scoring test. After 7 days of treatment there was a significant decrease of symptoms both in the total score (p less than 0.0001) and in regard to each AR symptom (p less than 0.01). On the whole, the sample reported no symptoms by day 7, and the resolution of symptoms occurred approximately at day 4. Furthermore, there was no need for supplementary treatment. Both the subjective global improvement impression and the QoL of patients appeared to significantly improve after treatment. No adverse events (AEs) were found globally. It can be concluded that propolis nasal spray effectively improves recovery from infectious AR and common cold symptoms in children and is an optimal alternative in the treatment of this disease without need for any adjuvant treatment.

Increase in gonorrhoea among very young adolescents, Catalonia, Spain, January 2012 to June 2013.

Between January 2012 and June 2013, 27 sexually transmitted infections were reported in adolescents aged 13-15 years in Catalonia, Spain. In the first half of 2013, there were nine cases of gonorrhoea, while in the same period of 2012, there was one. In June 2013, two gonorrhoea cases aged 13-14 years, linked to a common source through a social network, were reported. The public health response should be adapted to this vulnerable population.

[Malaria imported by immigrants]. / Paludismo importado por inmigrantes.

The immigrants from endemic zones who live in Europe are those with the greatest risk of acquiring malaria during trips to their countries, since they usually travel for longer than other travellers and to zones and under conditions of greater risk. The figures for the years 2002-2004 in Spain indicate that P. falciparum is the most diagnosed species. Africa is the continent from which most cases are imported and immigrants contribute 34-41% of all cases.

Paludismo importado por inmigrantes / Malaria imported by immigrants

Los inmigrantes de zonas endémicas que viven en Europa son los que más riesgo tienen de adquirir malaria durante los viajes a sus países, ya que suelen viajar durante más tiempo que el resto de viajeros y a zonas y en condiciones de más riesgo. Las cifras de los años 2002-2004 en España indican que P. falciparum es la especie más diagnosticada. África es el continente de donde se importan más casos y los inmigrantes contribuyen con el 34-41% de todos ellos

The immigrants from endemic zones who live in Europe are those with the greatest risk of acquiring malaria during trips to their countries, since they usually travel for longer than other travellers and to zones and under conditions of greater risk. The figures for the years 2002-2004 in Spain indicate that P. falciparum is the most diagnosed species. Africa is the continent from which most cases are imported and immigrants contribute 34-41% of all cases

Validación de la técnica de PCR para la detección de Escherichia coli enteroagregativa causante de diarrea del viajero / Validation of a PCR technique for the detection of enteroagreggative Escherichia coli causing traveler's diarrhea

Introducción. La detección de cepas de Escherichia coli enteroagregativas (ECEA) mediante la técnica de referencia (adherencia celular) presenta problemas de implementación metodológica en rutina hospitalaria. Métodos. Se validó la técnica de reacción en cadena de la polimerasa (PCR), en comparación con la de adherencia celular.Resultados. La PCR presentó, respecto a la técnica de adherencia a cultivo celular: sensibilidad de 0,93, especificidad de 1, valor predictivo positivo de 1 y valor predictivo negativo de 0,91. Conclusión. La PCR es alternativa viable para la detección habitual de cepas ECEA (AU)

Introduction. Detection of enteroaggregative strains of Escherichia coli (EAEC) by the gold standard technique (cellular adherence) is difficult to implement in routine clinical practice. Methods. The gold standard was compared with a PCR method for this purpose. Results. With respect to the cellular adherence technique, PCR performance was as follows: sensitivity 0.93, specificity 1, positive predictive value 1, and negative predictive value 0.91.Conclusion. The PCR method studied is a viable alternative for routine detection of EAEC strains (AU)

[Validation of a PCR technique for the detection of enteroagreggative Escherichia coli causing traveler's diarrhea]. / Validación de la técnica de PCR para la detección de Escherichia coli enteroagregativa causante de diarrea del viajero.

INTRODUCTION: Detection of enteroaggregative strains of Escherichia coli (EAEC) by the gold standard technique (cellular adherence) is difficult to implement in routine clinical practice. METHODS: The gold standard was compared with a PCR method for this purpose. RESULTS: With respect to the cellular adherence technique, PCR performance was as follows: sensitivity 0.93, specificity 1, positive predictive value 1, and negative predictive value 0.91. CONCLUSION: The PCR method studied is a viable alternative for routine detection of EAEC strains.

Norfloxacin decreases bacterial adherence of quinolone-resistant strains of Escherichia coli isolated from patients with cirrhosis.

BACKGROUND: Long-term administration of norfloxacin is recommended for secondary prophylaxis of spontaneous bacterial peritonitis in cirrhosis, but it may be associated with the development of quinolone-resistant bacteria in stools. However, these bacteria rarely cause infections. AIM: To assess bacterial adherence of either quinolone-sensitive or -resistant Escherichia coli obtained from stools of cirrhotic patients, as one of the main virulence factors, and its variations when sub-minimum inhibitory concentration of norfloxacin were added to the medium. METHODS: E. coli strains were co-cultured with oral epithelial cells obtained from patients in presence/absence of norfloxacin. Bacterial adherence was measured as percentage of cells exhibiting positive adherence and the number of bacteria attached to epithelial cells. RESULTS: 37 sensitive and 22 resistant E. coli strains were studied. Bacterial adherence was similar in both series (78% vs. 81%, P = N.S.), and these percentages were similarly and significantly reduced when subminimum inhibitory concentration of norfloxacin was added to the culture medium (P < 0.001). CONCLUSIONS: Bacterial adherence of E. coli obtained from patients with cirrhosis is unrelated to the sensitivity/resistance to quinolones, and is similarly reduced in both cases when subminimum inhibitory concentration of norfloxacin is added to the medium.

Bacterial DNA activates cell mediated immune response and nitric oxide overproduction in peritoneal macrophages from patients with cirrhosis and ascites.

BACKGROUND AND AIMS: Translocation of intestinal bacteria to ascitic fluid is probably the first step in the development of episodes of spontaneous bacterial peritonitis in patients with cirrhosis. We have recently reported the detection of bacterial DNA in blood and ascitic fluid from patients with advanced cirrhosis, what we consider as molecular evidence of bacterial translocation. Several studies have shown the immunogenic role of bacterial DNA in vitro, and we hypothesised that the presence of bacterial DNA could activate the type I immune response in peritoneal macrophages from these patients, leading to greater cytokine synthesis (interleukin (IL)-2 and IL-12, tumour necrosis factor alpha, and interferon gamma) and effector molecules such as nitric oxide. METHODS: Peritoneal macrophages obtained from patients with cirrhosis and culture negative non-neutrocytic ascitic fluid were collected and characterised by flow cytometry. Inducible nitric oxide synthase, nitric oxide levels, and cytokine production were measured by immunoenzymometric assays in basal and harvested conditions according to the presence/absence of bacterial DNA. RESULTS: The ability of peritoneal macrophages to synthesise nitric oxide and levels of all cytokines were significantly increased in patients with bacterial DNA. There was a positive correlation between inducible nitric oxide synthase and nitric oxide levels. CONCLUSIONS: The presence of bacterial DNA in patients with decompensated cirrhosis is associated with marked activation of peritoneal macrophages, as evidenced by nitric oxide synthesising ability, together with enhanced cytokine production.

Differential functional behavior of viral phi29, Nf and GA-1 SSB proteins.

DNA replication of phi29 and related phages takes place via a strand displacement mechanism, a process that generates large amounts of single-stranded DNA (ssDNA). Consequently, phage-encoded ssDNA-binding proteins (SSBs) are essential proteins during phage phi29-like DNA replication. In the present work we analyze the helix-destabilizing activity of the SSBs of phi29 and the related phages Nf and GA-1, their ability to eliminate non-productive binding of phi29 DNA polymerase to ssDNA and their stimulatory effect on replication by phi29 DNA polymerase in primed M13 ssDNA replication, a situation that resembles type II replicative intermediates that occur during phi29-like DNA replication. Significant differences have been appreciated in the functional behavior of the three SSBs. First, the GA-1 SSB is able to display helix-destabilizing activity and to stimulate dNTP incorporation by phi29 DNA polymerase in the M13 DNA replication assay, even at SSB concentrations at which the phi29 and Nf SSBs do not show any effect. On the other hand, the phi29 SSB is the only one of the three SSBs able to increase the replication rate of phi29 DNA polymerase in primed M13 ssDNA replication. From the fact that the phi29 SSB, but not the Nf SSB, stimulates the replication rate of Nf DNA polymerase we conclude that the different behaviors of the SSBs on stimulation of the replication rate of phi29 and Nf DNA polymerases is most likely due to formation of different nucleoprotein complexes of the SSBs with the ssDNA rather than to a specific interaction between the SSB and the corresponding DNA polymerase. A model that correlates the thermodynamic parameters that define SSB-ssDNA nucleoprotein complex formation with the functional stimulatory effect of the SSB on phi29-like DNA replication has been proposed.

Structural and functional comparative study of the complexes formed by viral ø29, Nf and GA-1 SSB proteins with DNA.

Single-stranded DNA-binding proteins have in common their crucial roles in DNA metabolism, although they exhibit significant differences in their single-stranded DNA binding properties. To evaluate the correlation between the structure of different nucleoprotein complexes and their function, we have carried out a comparative study of the complexes that the single-stranded DNA-binding proteins of three related bacteriophages, ø29, Nf and GA-1, form with single-stranded DNA. Under the experimental conditions used, ø29 and Nf single-stranded DNA-binding proteins are stable monomers in solution, while GA-1 single-stranded DNA-binding protein presents a hexameric state, as determined in glycerol gradients. The thermodynamic parameters derived from quenching measurements of the intrinsic protein fluorescence upon single-stranded DNA binding revealed (i) that GA-1 single-stranded DNA-binding protein occludes a larger binding site (n=51 nt/oligomer) than ø29 and Nf SSBs (n=3.4 and 4.7 nt/monomer, respectively); and (ii) that it shows a higher global affinity for single-stranded DNA (GA-1 SSB, K(eff)=18.6 x 10(5) M(-1); o29 SSB, K(eff)=2.2 x 10(5) M(-1); Nf SSB, K(eff)=2.9 x 10(5) M(-1)). Altogether, these parameters justify the differences displayed by the GA-1 single-stranded DNA-binding protein and single-stranded DNA complex under the electron microscope, and the requirement of higher amounts of ø29 and Nf single-stranded DNA-binding proteins than of GA-1 SSB in gel mobility shift assays to produce a similar effect. The structural differences of the nucleoprotein complexes formed by the three single-stranded DNA-binding proteins with single-stranded DNA correlate with their different functional stimulatory effects in ø29 DNA amplification.

Venous duplex scanning for unilateral symptoms: when do we need a contralateral evaluation?

OBJECTIVES: Determine the need for bilateral duplex scanning (DS) in patients with unilateral symptoms of acute DVT of the leg. DESIGN: Prospective study. MATERIALS: One thousand, one hundred and sixty-one consecutive patients with recent unilateral symptoms of pain or swelling. METHODS: Bilateral DS were performed and demographic data including risk factors for DVT were entered into a computerised database. RESULTS: Of the 250 cases (22%) of acute DVT, thrombus was confined to the symptomatic limb in 80% (200/250) and to the asymptomatic limb (AL) in 5% (12/250), while bilateral DVT was found in 15% (38/250). The management was not altered by the contralateral DS findings in any patient with bilateral thrombus. Ten of the 12 cases of DVT confined to the AL were localised to the infrapopliteal level; advanced malignancy, recent joint surgery or hypercoagulability were noted in nine patients, including all those requiring treatment. CONCLUSIONS: In the presence of unilateral symptoms of DVT, we recommend DS of the symptomatic extremity only; bilateral examination should be confined to patients with normal duplex findings in the symptomatic limb following recent joint surgery, or in the presence of advanced malignancy or hypercoagulability. Bilateral DS would therefore be required in approximately 11% of cases with unilateral symptoms of DVT.