Three-dimensional modeling and numerical predictions of multimodal nonlinear behavior in damaged concrete blocks.

In this paper, the multimodal nonlinear elastic behavior of concrete, which is representative of a consolidated granular material, is modeled numerically. Starting from a local three-dimensional softening law, the initial stiffness properties are re-estimated according to the local strain field. The experiments deal with samples of thermally damaged concrete blocks successively excited around their first three modes of vibration. The geometry of these samples cannot be described by a one-dimensional approximation in these experiments where compressional and shear motions are strongly coupled. Despite this added complexity, the nonlinear behavior for the three modes of vibration of the samples is well captured by the simulations using a single scalar nonlinear parameter appropriately integrated into the elasticity equations. It is shown that without sufficient attention paid to the latter, the conclusions would have brought erroneous statements such as nonlinearity dispersion or strain type dependence.

Characterization of the adverse effects of nicotine on placental development: in vivo and in vitro studies.

In utero exposure to nicotine is associated with increased risk of numerous adverse fetal and neonatal outcomes, which suggests that it acts directly to affect placental development and the establishment of the fetomaternal circulation (FC). This study used both in vivo [Wistar rats treated with 1 mg/kg nicotine from 2 wk prior to mating until gestational day (GD) 15] and in vitro (RCHO-1 cell line; treated with 10(-9) to 10(-3)M nicotine) models to examine the effects of nicotine on these pathways. At GD 15, control and treated placentas were examined for the impact of nicotine on 1) trophoblast invasion, proliferation, and degree of hypoxia, 2) labyrinth vascularization, 3) expression of key genes of placental development, and 4) expression of placental angiogenic factors. The RCHO-1 cell line was used to determine the direct effects of nicotine on trophoblast differentiation. Our in vivo experiments show that nicotine inhibits trophoblast interstitial invasion, increases placental hypoxia, downregulates labyrinth vascularization as well as key transcription factors Hand1 and GCM1, and decreases local and circulating EG-VEGF, a key placental angiogenic factor. The in vitro experiments confirmed the inhibitory effects of nicotine on the trophoblast migration, invasion, and differentiation processes and demonstrated that those effects are most likely due to a dysregulation in the expression of nicotine receptors and a decrease in MMP9 activity. Taken together, these data suggest that adverse effects of maternal smoking on pregnancy outcome are due in part to direct and endocrine effects of nicotine on the main processes of placental development and establishment of FC.

Applying diffuse ultrasound under dynamic loading to improve closed crack characterization in concrete.

Recent studies show the ability of diffuse ultrasound to characterize surface breaking cracks in concrete. However, derived parameters are sensitive to the presence of partially opened zones along the crack whose pattern may differ from one sample to another. The aim of this letter is to study the variation of diffuse ultrasound parameters while the sample is driven by a low frequency bending load which alternatively opens and closes the crack, allowing to access supplementary information about its morphology. The results show the sensitivity of the method for various crack depths and highlight its potential for concrete nondestructive evaluation.

[Predictive factors of acquisition of epidemic extended-spectrum beta-lactamase-producing Escherichia coli]. / Etude des facteurs prédictifs d'acquisition d'une souche épidémique d'Escherichia coli productrice de bêta-lactamase à spectre étendu.

The aim of the study was to determine predictive factors of epidemic extended spectrum beta-lactamase-producing Escherichia coli acquisition. All patients presenting any type of culture positive for ESBL-producing E. coli between November 2006 and October 2007 were included. An epidemic case was defined as a patient colonized with a clonal strain having epidemiological link with an another patient harbouring the same strain. Clinical and administrative data were recorded. Groups were compared by univariate and multivariate analysis using SAS software. Were included in this study 148 patients: 60 epidemic and 88 sporadic cases. Multivariate analysis showed several predictive factors of epidemic strain acquisition: female gender, high Charlson index, treatment by amoxicillin or ticarcillin-clavulanic acid, admission to emergency unit and hospitalisation in a high number of different care units. Identification of predictive factors of epidemic ESBL-producing E. coli strains acquisition may help to limit cross transmission of such strains.

[Is it possible to detect Staphylococcus aureus colonization or bacteriuria before orthopedic surgery hospitalization?]. / Le dépistage en ambulatoire des patients porteurs de Staphylococcus aureus ou présentant une colonisation urinaire et devant bénéficier d'une chirurgie orthopédique est-il réaliste ?

AIM OF THE STUDY: Evaluate the feasibility of Staphylococcus aureus nasal colonization and bacteriuria screening in outpatients before realizing a decolonization treatment in S. aureus carriers and a bacteriuria treatment before hospitalization. METHODS: All patients undergoing hip, knee or back surgery in which prosthesis were implanted between October 2007 until the end of June 2008 were included. Microbiological studies were performed before hospitalization. Notice for S. aureus decolonization regimen was delivered to each patient and to the general practitioner only if the patient had nasal carriage. RESULTS: Only 91.2% (240/263) of patients had microbiological results. Prevalence of S. aureus colonization was 21.4% (48 positives/224). Three patients were colonized with methicillin-resistant staphylococci. Decolonization regimen was applied before surgery to 70.8% (n=34) of the colonized patients. Among the patients, 8.9% (20/225) had bacteriuria, Escherichia coli being the most frequent micro-organism (n=16). CONCLUSION: Preoperative search and management of S. aureus colonization and of bacteriuria in outpatients is possible. Monitoring record must be performed by a member of the hospital staff.

[Real-time PCR for fast detection of plasmid-mediated qnr genes in extended spectrum beta-lactamase producing Enterobacteriaceae]. / Mise au point d'une technique de PCR en temps réel pour la détection rapide des gènes qnr chez des entérobactéries productrices de bêta-lactamases à spectre étendu.

AIM OF THE STUDY: To develop a fast and reliable real time PCR technique for detecting plasmid-mediated quinolone resistance genes qnrA, qnrB and qnrS. METHODS: A real-time PCR assay using SYBR Green I and Roche LightCycler(®) was developed to detect qnr genes. Detection of qnr genes was based on comparison of melting temperature differences with a positive control of each qnr genes. This assay was performed to study 138 isolates collected from diagnostic and screening samples in the Champagne-Ardenne region in 2004 (France). RESULTS: In optimized conditions, the three positive controls tested alone and with isolates confirmed the specificity of the PCR primers. Each PCR assay was able to test 30 strains in 60min for 1 qnr gene. Out of 138 isolates screened, 3.6 % isolates were positive for a qnrA1, 1.5 % for qnrS1 and no qnrB-like gene. Prevalence of qnr determinants was 5 % and reached 9.5 % in clinical isolates. CONCLUSION: Real-time PCR is a fast and reliable technique for screening of qnr-positive strains. This study shows a relatively high prevalence of qnr determinants (5 %) among ESBL-producing Enterobacteriaceae.

Effect of the presence and size of a localized nonlinear source in concrete.

The aim of the present letter is to identify the contribution of a macroscopic source of elastic nonlinearity in concrete, a medium which by nature is nonlinear, and belongs to the nonlinear mesoscopic class of materials. The influence of real, localized macro-cracks is characterized with respect to the intrinsic nonlinearity of the material. The influence of the size of the source on the amplitude of the measured nonlinearity is qualitatively demonstrated. A comparison is made between the changes in linear and nonlinear parameters.

Short duration of post-amputation antibiotic therapy in diabetic foot patients with total resection of osteomyelitis.

BACKGROUND: Short duration of post-amputation antibiotic therapy (2-5 days) is recommended in patients with diabetic foot osteomyelitis after total resection of infected bone tissue. OBJECTIVE: To evaluate the long-term effectiveness of short-duration post-amputation antibiotic therapy in diabetic patients with total resection of osteomyelitis assessed by sterile bone bacteriological samples obtained from the resection margin. METHODS: The endpoint was the absence of osteomyelitis relapse at 6 months, defined as recurrence of osteomyelitis with the need for surgical revision and/or new bone antibiotic therapy. RESULTS: Among 15 patients included, 12 (80%) were cured without recurrence of osteomyelitis at 6 months, with a mean duration of antibiotic therapy of 8.3±5.9 days post surgery. This result is comparable to literature data, while all of them reported longer duration of antibiotic therapy and/or shorter follow-up. CONCLUSION: Short duration of post-amputation antibiotic therapy in diabetic patients with sterile bacteriological samples obtained from resection margin seems effective.

Are systematic drain tip or drainage fluid cultures predictive of surgical site infections?

Systematic cultures of drain tips or drainage fluids for the early detection of surgical site infections (SSIs) are controversial. To examine the association between the results of systematic drain tip or drainage fluid cultures and the occurrence of SSIs in clean or clean-contaminated surgery. Searches were performed in the PubMed, and Cat.inist databases for observational studies published before 31st March 2017. Studies reporting results of drain tip or drainage fluid systematic cultures and SSIs after clean or clean-contaminated surgeries were included, and meta-analyses were performed. Seventeen studies, including 4390 patients for drain tip cultures and 1288 for drainage fluid cultures, were selected. The pooled negative predictive values were high (99%, 95% confidence interval (CI) 98-100 for drain tip cultures and 98%, 95% CI 94-100 for drainage fluid cultures). The positive predictive values were low (11%, 95% CI 2-24 for drain tip cultures and 12%, 95% CI 3-24 for drainage fluid cultures). The sensitivities were low (41%, 95% CI 12-73 for drain tip cultures and 37%, 95% CI 16-60 for drainage fluid cultures). The specificities were high (93%, 95% CI 88-96) for drain tip cultures and moderate (77%, 95% CI 54-94) for drainage fluid cultures. Systematic cultures of drain tips or drainage fluids appear not to be relevant, because their positive predictive values were low in the prediction of SSIs.

Knowledge of antibiotics and antibiotic resistance in patients followed by family physicians.

OBJECTIVE: We aimed to evaluate factors associated with knowledge of antibiotics and drug resistance. METHODS: A questionnaire was handed out by 14 family physicians to their patients between December 20, 2014 and April 20, 2015 in Rethel (North-East of France). We conducted a cross-sectional study using a logistical regression model to assess factors associated with antibiotic knowledge. Three criteria were used to assess that knowledge. RESULTS: Overall, 293 questionnaires were analysed; 48% of patients had received antibiotics in the previous 12 months. Only 44% and 26% gave a correct answer for the statements "Antibiotics are effective against bacteria and ineffective against viruses" and "Antibiotic resistance decreases if the antibiotic use decreases", respectively. Characteristics such as female sex, age>30 years, high level of education, high professional categories, and having received antibiotic information by the media were associated with high level of knowledge about antibiotics and/or antibiotic resistance. In contrast, having received antibiotic information from family physicians was not associated with good knowledge. CONCLUSION: Although media awareness campaigns had an independent impact on a higher public knowledge of antibiotics, the overall public knowledge remains low. It would be necessary to strengthen antibiotic campaigns with clearer information on the relation between the excessive use of antibiotics and the increased risk of antibiotic resistance. Family physicians should be more involved to improve antibiotic knowledge among target groups such as men, young patients, and people from a poor social and cultural background.

Dynamic acousto-elastic test using continuous probe wave and transient vibration to investigate material nonlinearity.

This study demonstrates the feasibility of the dynamic acousto-elastic effect of a continuous high frequency wave for investigating the material nonlinearity upon transient vibration. The approach is demonstrated on a concrete sample measuring 15×15×60cm(3). Two ultrasonic transducers (emitter and receiver) are placed at its middle span. A continuous high frequency wave of 500kHz propagates through the material and is modulated with a hammer blow. The position of the hammer blow on the sample is configured to promote the first bending mode of vibration. The use of a continuous wave allows discrete time extraction of the nonlinear behavior by a short-time Fourier transform approach, through the simultaneous comparison of a reference non-modulated signal and an impact-modulated signal. The hammer blow results in phase shifts and variations of signal amplitude between reference and perturbed signals, which are driven by the resonant frequency of the sample. Finally, a comprehensive analysis of the relaxation mechanisms (modulus and attenuation recovery) is conducted to untangle the coupled fast and slow hysteretic effects.

Decline in antibiotic resistance and changes in the serotype distribution of Streptococcus pneumoniae isolates from children with acute otitis media; a 2001-2011 survey by the French Pneumococcal Network.

Streptococcus pneumoniae is an important cause of acute otitis media (AOM). The aim of this study was to evaluate trends in antibiotic resistance and circulating serotypes of pneumococci isolated from middle ear fluid of French children with AOM during the period 2001-2011, before and after the introduction of the PCV-7 (2003) and PCV-13 (2010) vaccines. Between 2001 and 2011 the French pneumococcal surveillance network analysed the antibiotic susceptibility of 6683 S. pneumoniae isolated from children with AOM, of which 1569 were serotyped. We observed a significant overall increase in antibiotic susceptibility. Respective resistance (I+R) rates in 2001 and 2011 were 76.9% and 57.3% for penicillin, 43.0% and 29.8% for amoxicillin, and 28.6% and 13.0% for cefotaxime. We also found a marked reduction in vaccine serotypes after PCV-7 implementation, from 63.0% in 2001 to 13.2% in 2011, while the incidence of the additional six serotypes included in PCV-13 increased during the same period, with a particularly high proportion of 19A isolates. The proportion of some non-PCV-13 serotypes also increased between 2001 and 2011, especially 15A and 23A. Before PCV-7 implementation, most (70.8%) penicillin non-susceptible pneumococci belonged to PCV-7 serotypes, whereas in 2011, 56.8% of penicillin non-susceptible pneumococci belonged to serotype 19A. Between 2001 and 2011, antibiotic resistance among pneumococci responsible for AOM in France fell markedly, and PCV-7 serotypes were replaced by non-PCV-7 serotypes, especially 19A. We are continuing to assess the impact of PCV-13, introduced in France in 2010, on pneumococcal serotype circulation and antibiotic resistance.

A GppNHp-insensitivity factor modulates the activation of beta-adrenoceptor-coupled Gs protein in rat cortex and cerebellum.

The effect known as the GTP-shift refers to the complete conversion of receptors from the high- to the low agonist-affinity state in the presence of an excess of GTP or one of its analogs. 5'-Guanylylimidodiphosphate (GppNHp) was able to fully suppress the high (-)-isoproterenol-affinity of beta-adrenoceptors (beta AR) in cultured rat brain astrocytes. In contrast, a proportion of beta AR in rat cortex and cerebellum synaptosomes was found to be insensitive to this GTP analog. This GppNHp-insensitivity was due to a membrane-associated factor, presumably interacting with Gs proteins and not present in a functional form in cultured astrocytes. Here we assessed the effect of this factor on the beta AR-mediated activation of Gs proteins. The removal of the GppNHp-insensitivity factor from the synaptosomes was achieved using 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate (CHAPS), a mild detergent. The activation of Gs proteins was monitored by the binding of another non-hydrolysable GTP-analog, guanylyl 5'-[gamma-[35S]thio]-triphosphate ([35S]GTP gamma S). The beta AR-Gs protein coupling was at least twofold less efficient in synaptosomes relative to cultured astrocytes. The CHAPS treatment induced a twofold increase in the coupling efficiency in cortex and cerebellum synaptosomes, but had no effect in cultured astrocytes. It undoubtedly indicated the inhibitory effect of the GppNHp-insensitivity factor on the activation of Gs proteins in the synaptosomes. Using CHAPS-soluble material extracted from synaptosomes, it was possible to reconstitute the GppNHp-insensitivity of CHAPS-treated membranes or even to induce it in cultured astrocytes. This effect correlated with the amount of CHAPS-soluble material according to a sigmoid curve, but it was abolished by the heat of CHAPS-soluble material. Successful crossed reconstitutions of the GppNHp-insensitivity suggest that the GppNHp-insensitivity factor is the same regardless of its originating area, and that it might play a general role in the central nervous system. Further investigations should help to identify the GppNHp-insensitivity factor.

A program to help asthmatic students reach their potential.

Asthma is the most common chronic disease of childhood, affecting 15 percent of Americans under the age of 15. It ranks first among the chronic disease in causing school absenteeism, and it has been linked to lowered academic performance. An educational program for elementary school teachers has been developed to assist the asthmatic student in reaching his or her potential. The program addresses needs expressed by members of the Montgomery, Ala., chapter of Parents of Asthmatic Kids (PAK). These parents voiced concern regarding the inadequate preparation of teachers for dealing with the needs of the asthmatic student. Results of a survey of teachers in local elementary schools confirmed their need for asthma education. The program, consisting of an audiovisual presentation, an informative brochure, and an instructional packet to use with first to sixth graders, is designed to be presented in faculty meetings throughout the school system. To evaluate the effectiveness of the module, a simple test is administered before and after the program. The program has been accepted by the American Lung Association of Alabama and is under consideration by the American Lung Association at the national level.

Viability and freezing ability of rabbit embryos collected in the vagina after prostaglandin treatment.

Morulae were collected from rabbit vaginas after prostaglandin treatment 65h post coitum. The optimum embryo recovery was obtained when the flushings started around 12h after the prostaglandin injection. The mean embryo collection was around 10 embryos per animal. These embryos had the same viability as those collected by the classical technique of uterine flushing (around 80%). The freezing ability of these embryos was also similar to that observed for uterus-collected embryos. Embryos not ejected after the treatment can develop in vivo and give birth to living progeny. The results obtained suggest that this technique can be used for egg transfer in rabbit genetic improvement programs.

The effect of sucrose and trehalose on viability of one- and two-cell rabbit embryos.

The effect of sucrose and trehalose on the viability of one- and two-cell rabbit embryos was investigated. A significant decrease in the viability of one- and two-cell embryos exposed for 30 min. at 20 degrees C was observed. At 38 degrees C none of the two-cell embryos in a sucrose solution survived after 30 min exposure, while approximately 50% of the embryos survived in a trehalose solution. The cleveage rate in culture of two-cell embryos exposed both to 2.0 M or 1.45 M trehalose was significantly lower in comparison with the control group. However the survival rate after transfer of two-cell embryos exposed to 1.45 M trehalose solution at 20 degrees C remained the same as that of the control group.

Transfer of frozen-thawed embryos in sheep.

Embryos collected from ewes six days after oestrus were frozen in straws using ethylene-glycol as a cryoprotectant. The efficiency of the simplified freezing and thawing procedure was assessed after transfer, which resulted in an overall survival rate of 58.3 per cent. Forty-two lambs were born from 72 frozen embryos which had been transferred without any attempt to evaluate them after the thawing and sucrose dilution process.

[Infection on foreign material: bacterial colonization of ureteral endoprostheses]. / Infection sur matériel étranger: colonisation bactérienne des endoprothèses urétérales.

Infection on foreign body: bacterial colonization of ureteric stents. The most frequent cause of the early removal of ureteric endoprostheses (double J) is generally due to bacterial colonization. In order to prevent or to restrict the prosthesis colonization, it is necessary to understand the major steps and the factors influencing the colonization. This is the reason why we aimed to extract the most relevant parameters influencing the bacterial colonization from the observations made in vivo thanks to in vitro analyses. We have studied in vivo the relationship between the bacterial colonization of the endoprostheses, the urinary infections and the antibiotherapy. In vitro, we have defined the conditions promoting the primary adhesion of the most frequently isolated bacteria on endoprostheses. Surface properties of bacteria and materials have been compared to:--the bacterial count of infected double J samples with respect to bacterial species,--the bacterial count of the infected samples with respect to pH and Ca2+, Mg2+ concentration. The results show a great variability of the biomaterial surface properties which could be optimized, the fact that the urinary medium acidification could lower the bacterial adhesion and the ambiguous role of Ca2+ and Mg2+ ions which is discussed in this paper. In the case of in vivo analyses, the conflicting results between leukocyturia and bacteriuria lead to the detection of the bacterial colonization under antibiotic treatment. The characterized urinary infection must warn the risk of pyelonephritis.