International nosocomial infection control consortium (INICC) report, data summary of 36 countries, for 2004-2009

The results of a surveillance study conducted by the International Nosocomial Infection Control Consortium (INICC) from January 2004 through December 2009 in 422 intensive care units (ICUs) of 36 countries in Latin America, Asia, Africa, and Europe are reported. During the 6-year study period, using Centers for Disease Control and Prevention (CDC) National Healthcare Safety Network (NHSN; formerly the National Nosocomial Infection Surveillance system [NNIS]) definitions for device-associated health care-associated infections, we gathered prospective data from 313,008 patients hospitalized in the consortium's ICUs for an aggregate of 2,194,897 ICU bed-days. Despite the fact that the use of devices in the developing countries' ICUs was remarkably similar to that reported in US ICUs in the CDC's NHSN, rates of device-associated nosocomial infection were significantly higher in the ICUs of the INICC hospitals; the pooled rate of central line-associated bloodstream infection in the INICC ICUs of 6.8 per 1,000 central line-days was more than 3-fold higher than the 2.0 per 1,000 central line-days reported in comparable US ICUs. The overall rate of ventilator-associated pneumonia also was far higher (15.8 vs 3.3 per 1,000 ventilator-days), as was the rate of catheter-associated urinary tract infection (6.3 vs. 3.3 per 1,000 catheter-days). Notably, the frequencies of resistance of Pseudomonas aeruginosa isolates to imipenem (47.2% vs 23.0%), Klebsiella pneumoniae isolates to ceftazidime (76.3% vs 27.1%), Escherichia coli isolates to ceftazidime (66.7% vs 8.1%), Staphylococcus aureus isolates to methicillin (84.4% vs 56.8%), were also higher in the consortium's ICUs, and the crude unadjusted excess mortalities of device-related infections ranged from 7.3% (for catheter-associated urinary tract infection) to 15.2% (for ventilator-associated pneumonia). Copyright © 2012 by the Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved

Matériaux ferromagnétiques et ferroélectriques pour l’énergie : composites multicaloriques

Solid-state refrigeration is an alternative method of cooling matter using a magnetic orelectrical stimulus, replacing conventional refrigeration systems, which are more energy-intensive and environmentally damaging. In the last years, a reasonable interest has beengiven to studying magnetocaloric and electrocaloric materials, while the research of mate-rials with interesting multicaloric effect near room temperature is only at the beginning.In this thesis, we are interested in elaborating new magnetic material with an interes-ting magnetocaloric effect around room temperature, presenting a second-order magneticphase transition from the ferromagnetic state to paramagnetic one, less expensive thanGd and more resistant to corrosion than Gd. We chose the material Pr2Fe17 as a startingcompound that is a potential candidate for magnetic refrigeration. We succeeded in op-timizing the Curie temperature value by a substitution in the rare-earth site of the Pratom by the Sm atom. The structural study of the compound (Pr,Sm)2Fe17 with Riet-veld refinement shows that the compound crystallizes in the same space group as Pr2Fe17 (R ̄3m). The study of the phase transition according to the Landau model proves that (Pr,Sm)2Fe17 exhibits a second-order phase transition. The order of the phase transition is a significant factor for magnetocaloric materials ; it has also been verified by the Arrott plot method and the universal magnetic entropy curve method. For (Pr,Sm)2Fe17, the value of RCP is about 159,4 J.kg−1 for a magnetic field variation of 2 T, which corres- ponds to about 75% of the one observed in pure Gd and which makes our compound a potential candidate for the magnetic refrigeration around the ambient temperature. To study in details the magnetic phase transition of the compound (Pr,Sm)2Fe17, we have performed a complete study of the critical phenomenon in the vicinity of the FM-PM phase transition in Pr2Fe17 and (Pr,Sm)xFe17. We find that the values of the determined critical exponents are close to 3D-Ising spins [d = 3 : n = 1] coupled to an interaction at the boundary between a long-range and a short-range type interaction (sigma = 1.95).The spin interaction decays as J(r)=r−4.95. To study new magnetocaloric systems, we areinterested in the intermetallic compounds PrCo5−xCux which present structural and ma-gnetic properties different from those of the Pr2Fe17 system. Substituting the cobalt atomwith copper leads to a considerable decrease in the Curie temperature from 950 K to 310 K for x=3. The PrCo5−xCux compounds present three transition temperatures accompanied by an entropy change ; this makes the PrCo5−xCux system a good candidate for magnetic refrigeration with three operating temperatures. To associate an electrocaloric material with the compound (Pr,Sm)2Fe17 to combine magnetism and ferroelectricity via multiferroicity, we started with a study of the electrocaloric effect in BaTiO3 and Ba0.7Sr0.3TiO3, the electrocaloric effect has been calculated with an indirect method based on Maxwell’s entropy relation. The multicaloric composites were elaborated by an assembly between BST ceramic and intermetallic pellets. The intermetallic pellets were prepared by conventional vacuum sintering. A description of the device, the principle of measurement and the results of the magnetoelectric coupling have been realized.Key words : Intermetallic, ferromagnetism, magnetocaloric materials,magneticrefrigeration, dielectric materials, ferroelectric, electrocaloric materials, mul-tiferroic materials, multicaloric materials, solid state refrigeration, EnergyLa réfrigération à l’état solide est un moyen alternatif pour refroidir la matière enutilisant un stimulus magnétique ou électrique. Elle peut remplacer les systèmes de réfri-gération classiques, qui sont plus coûteux de point de vue énergétique et plus nuisibles àl’environnement. Ces dernières années, un intérêt raisonnable a été accordé à l’étude desmatériaux magnétocaloriques et éléctrocaloriques, alors que la recherche des matériaux àeffet multicalorique intéressant autour de la température ambiante n’est qu’à ses débuts.Dans cette thèse, nous nous intéressons en premier lieu à l’élaboration d’un nouveau matériau magnétique à effet magnétocalorique intéressant autour de la température ambiante, un matériau qui présente une transition magnétique de type ferromagnétique paramagnétique de second ordre, moins cher et plus résistant à la corrosion que le Gd. Nous avons choisi le Pr2Fe17 comme composé de départ qui est potentiellement candidat pour la réfrigération magnétique. Nous avons réussi à optimiser la valeur de sa température de Curie par une substitution dans le site de la terre rare (Pr) par l’atome Sm. L’étude structurale du composé (Pr,Sm)2Fe17 avec l’affinement de Rietveld montre que le composé cristallise dans le même groupe d’espace que Pr2Fe17 (R ̄3m). L’étude de la transition de phase selon le modèle de Landau prouve que (Pr,Sm)2Fe17 présente une transition de phase de second ordre. Pour le composé (Pr,Sm)2Fe17, la valeur de RCP est d’environ 160 J.kg−1 pour une variation de champ magnétique de 2 T, ce qui correspond à environ 75% de celle observée dans le Gd pur, ceci fait de ce composé un candidat potentiel pour la réfrigération magnétique. Dans le but d’étudier en détail la transition de phase magnétique du composé (Pr,Sm)2Fe17, nous avons réalisé une étude complète du phénomène critique au voisinage de la transition de phase FM-PM dans Pr2Fe17 et (Pr,Sm)2Fe17. On trouve que les valeurs des exposants critiques déterminés sont proches des spins 3D-Ising [d = 3 :n = 1] couplés à une interaction à la limite entre une interaction de type longue portée et une interaction de type courte portée (σ =1,95), cette intéraction des spins décroît comme J(r)=r−4,95. Dans le but d’étudier de nouveaux systèmes magnétocaloriques, nous nous sommes intéressés aux composés intermétalliques PrCo5−xCux qui présentent des propriétés structurales et magnétiques différentes à celles de système Pr2Fe17. La substitution de l’atome de cobalt par le cuivre a pour effet de diminuer considérablement la valeur de la température de Curie de 950 K à 300 K pour x=3. Les composés PrCo5−xCux présentent trois températures de transition accompagnées d’un un changement d’entropie magnétique, ceci fait que le système PrCo5−xCux est un bon candidat pour la réfrigération magnétique avec trois températures de fonctionnement. En vue d’élaborer un matériau multicalorique, nous avons associé un matériau diélectrique à effet électrocalorique avec le composé magnétocalorique (Pr,Sm)2Fe17. Dans cette étude, nous avons commencé par la caractérisation de l’effet électrocalorique dans les composés BaTiO3 et Ba0.7Sr0.3TiO3, l’effet électrocalorique a été calculé avec une méthode indirecte basée sur la relation de Maxwell de l’entropie. Les composites magnétoélectriques multicaloriques ont été élaborés par un assemblage entre la céramique BST et des pastilles intermétalliques. Une descrip-tion du dispositif, le principe de mesure du couplage magnétoélectrique, ainsi que, la mésure du coefficient du couplage magnétoélectrique ont été réalisés.Mots clés : Intermétallique, ferromagnétisme, matériaux magnétocaloriques,réfrigération magnétique, matériaux diélectriques-ferroélectriques, matériauxélectrocaloriques, matériaux multiferroïques, matériaux multicaloriques, réfri-gération à l’état solide, énergie

Investigation of Magnetic Entropy Change in Intermetallic Compounds SmNi3−xFex Based on Maxwell Relation and Phenomenological Model

In this study, we investigate the crystal structure, magnetic, and magnetocaloric effect properties in the intermetallic compounds SmNi3−xFex using a phenomenological model based on Landau mean-field theory and Maxwell relation (conventional method). SmNi3−xFex compounds were prepared under high pure argon by arc melting. To minimize the amount of other possible impurity phases, the ingots were heat-treated at 1073 K for seven days. X-ray diffraction (XRD) under and without an applied magnetic field was used for the structural study. Rietveld analysis with FullProf computer code was used to analyze X-ray diffraction data. The magnetization against temperature was measured under several applied magnetic fields. After the partial substitutions of nickel atom with iron one, we notice an increase of cell parameters. In addition, Curie temperature value increases significantly with the increase of iron content. According to the Landau model, SmNi3−xFex compounds exhibit a second-order magnetic phase transition. The magnetic entropy change was determined with theoretical and experimental methods. Finally, a comparison between theoretical magnetic entropy change and the experimental show an agreement between the two methods

Exploring Crystal Structure, Hyperfine Parameters, and Magnetocaloric Effect in Iron-Rich Intermetallic Alloy with ThMn₁₂-Type Structure: A Comprehensive Investigation Using Experimental and DFT Calculation

In this study, we give a thorough evaluation of the structural, magnetic, and magnetocaloric properties in iron-rich PrFe11Ti intermetallic alloy with ThMn12-type structure using a combination of experimental and theoretical analysis. X-ray diffraction coupled with Rietveld refinement was used to characterize the structure, which revealed a unique tetragonal crystal structure with I4/mmm space group. The 8i site was identified as the preferred site for the Ti atom. This finding was confirmed by various techniques, including XRD, DFT, and Mössbauer spectrometry. Magnetic properties were studied through intrinsic magnetic measurements and magnetocaloric effect analysis. Mössbauer spectroscopy was employed to probe the local magnetic environment and for further characterization of the material’s magnetic properties. The experimental results were complemented by theoretical calculations based on density functional theory (DFT). A promising magnetocaloric effect is observed, with a significant maximum magnetic entropy (−ΔSMmax = 2.5 J·kg−1·K−1) and a relative cooling power about 70 J·kg−1 under low magnetic field change μ0ΔH = 1.5 T. Overall, our results provide a deeper understanding of the structural and magnetic properties of the material under study and demonstrate the effectiveness of the combined experimental and theoretical approach in the investigation of complex materials. The insights gained from this study could have implications for the development of advanced magnetic materials with enhanced properties for potential magnetic applications

Investigation of Magnetic Entropy Change in Intermetallic Compounds SmNi_3−<i>x</i>Fe_<i>x</i> Based on Maxwell Relation and Phenomenological Model

In this study, we investigate the crystal structure, magnetic, and magnetocaloric effect properties in the intermetallic compounds SmNi3−xFex using a phenomenological model based on Landau mean-field theory and Maxwell relation (conventional method). SmNi3−xFex compounds were prepared under high pure argon by arc melting. To minimize the amount of other possible impurity phases, the ingots were heat-treated at 1073 K for seven days. X-ray diffraction (XRD) under and without an applied magnetic field was used for the structural study. Rietveld analysis with FullProf computer code was used to analyze X-ray diffraction data. The magnetization against temperature was measured under several applied magnetic fields. After the partial substitutions of nickel atom with iron one, we notice an increase of cell parameters. In addition, Curie temperature value increases significantly with the increase of iron content. According to the Landau model, SmNi3−xFex compounds exhibit a second-order magnetic phase transition. The magnetic entropy change was determined with theoretical and experimental methods. Finally, a comparison between theoretical magnetic entropy change and the experimental show an agreement between the two methods

Findings of the International Nosocomial Infection Control Consortium (INICC), Part III Effectiveness of a Multidimensional Infection Control Approach to Reduce Central Line—Associated Bloodstream Infections in the Neonatal Intensive Care Units of 4 Developing Countries

OBJECTIVE. To analyze the impact of the International Nosocomial Infection Control Consortium (INICC) multidimensional infection control approach to reduce central line-associated bloodstream infection (CLABSI) rates. SETTING. Four neonatal intensive care units (NICUs) of INICC member hospitals from El Salvador, Mexico, Philippines, and Tunisia. PATIENTS. A total of 2,241 patients hospitalized in 4 NICUs for 40,045 bed-days. METHODS. We conducted a before-after prospective surveillance study. During Phase 1 we performed active surveillance, and during phase 2 the INICC multidimensional infection control approach was implemented, including the following practices: (1) central line care bundle, (2) education, (3) outcome surveillance, (4) process surveillance, (5) feedback of CLABSI rates, and (6) performance feedback of infection control practices. We compared CLABSI rates obtained during the 2 phases. We calculated crude stratified rates, and, using random-effects Poisson regression to allow for clustering by ICU, we calculated the incidence rate ratio (IRR) for each follow-up time period compared with the 3-month baseline. RESULTS. During phase 1 we recorded 2,105 CL-days, and during phase 2 we recorded 17,117 CL-days. After implementation of the multidimensional approach, the CLABSI rate decreased by 55%, from 21.4 per 1,000 CL-days during phase 1 to 9.7 per 1,000 CL-days during phase 2 (rate ratio, 0.45 [95% confidence interval, 0.33-0.63]). The IRR was 0.53 during the 4-12-month period and 0.07 during the final period of the study (more than 45 months). CONCLUSIONS. Implementation of a multidimensional infection control approach was associated with a significant reduction in CLABSI rates in NICUs. Infect Control Hosp Epidemiol 2013;34(3):229-23

Identification of novel pathogenic MSH2 mutation and new DNA repair genes variants: investigation of a Tunisian Lynch syndrome family with discordant twins

International audienceBackground: Lynch syndrome (LS) is a highly penetrant inherited cancer predisposition syndrome, characterized by autosomal dominant inheritance and germline mutations in DNA mismatch repair genes. Despite several genetic variations that have been identified in various populations, the penetrance is highly variable and the reasons for this have not been fully elucidated. This study investigates whether, besides pathogenic mutations, environment and low penetrance genetic risk factors may result in phenotype modification in a Tunisian LS family. Patients and methods: A Tunisian family with strong colorectal cancer (CRC) history that fulfill the Amsterdam I criteria for the diagnosis of Lynch syndrome was proposed for oncogenetic counseling. The index case was a man, diagnosed at the age of 33 years with CRC. He has a monozygotic twin diagnosed at the age of 35 years with crohn disease. Forty-seven years-old was the onset age of his paternal uncle withCRC. An immunohistochemical (IHC) labeling for the four proteins (MLH1, MSH2, MSH6 and PMS2) of the MisMatchRepair (MMR) system was performed for the index case. A targeted sequencing of MSH2, MLH1 and a panel of 85 DNA repair genes was performed for the index case and for his unaffected father. Results: The IHC results showed a loss of MSH2 but not MLH1, MSH6 and PMS2 proteins expression. Genomic DNA screening, by targeted DNA repair genes sequencing, revealed an MSH2 pathogenic mutation (c.1552C>T; p.Q518X), confirmed by Sanger sequencing. This mutation was suspected to be a causal mutation associated to the loss of MSH2 expression and it was found in first and second degree relatives. The index case has smoking and alcohol consumption habits. Moreover, he harbors extensive genetic variations in other DNA-repair genes not shared with his unaffected father. Conclusion: In our investigated Tunisian family, we confirmed the LS by IHC, molecular and in silico investigations. We identified a novel pathogenic mutation described for the first time in Tunisia. These results come enriching the previously reported pathogenic mutations in LS families. Our study brings new arguments to the interpretation of MMR expression pattern and highlights new risk modifiers genes eventually implicated in CRC. Twins discordance reported in this work underscore that disease penetrance could be influenced by both genetic background and environmental factors