Measurement of biologically available naphthalene in gas and aqueous phases by use of a Pseudomonas putida biosensor.

Genetically constructed microbial biosensors for measuring organic pollutants are mostly applied in aqueous samples. Unfortunately, the detection limit of most biosensors is insufficient to detect pollutants at low but environmentally relevant concentrations. However, organic pollutants with low levels of water solubility often have significant gas-water partitioning coefficients, which in principle makes it possible to measure such compounds in the gas rather than the aqueous phase. Here we describe the first use of a microbial biosensor for measuring organic pollutants directly in the gas phase. For this purpose, we reconstructed a bioluminescent Pseudomonas putida naphthalene biosensor strain to carry the NAH7 plasmid and a chromosomally inserted gene fusion between the sal promoter and the luxAB genes. Specific calibration studies were performed with suspended and filter-immobilized biosensor cells, in aqueous solution and in the gas phase. Gas phase measurements with filter-immobilized biosensor cells in closed flasks, with a naphthalene-contaminated aqueous phase, showed that the biosensor cells can measure naphthalene effectively. The biosensor cells on the filter responded with increasing light output proportional to the naphthalene concentration added to the water phase, even though only a small proportion of the naphthalene was present in the gas phase. In fact, the biosensor cells could concentrate a larger proportion of naphthalene through the gas phase than in the aqueous suspension, probably due to faster transport of naphthalene to the cells in the gas phase. This led to a 10-fold lower detectable aqueous naphthalene concentration (50 nM instead of 0.5 micro M). Thus, the use of bacterial biosensors for measuring organic pollutants in the gas phase is a valid method for increasing the sensitivity of these valuable biological devices.

Diagnosing pulmonary embolism in outpatients with clinical assessment, D-dimer measurement, venous ultrasound, and helical computed tomography: a multicenter management study.

PURPOSE: To evaluate a diagnostic strategy for pulmonary embolism that combined clinical assessment, plasma D-dimer measurement, lower limb venous ultrasonography, and helical computed tomography (CT). METHODS: A cohort of 965 consecutive patients presenting to the emergency departments of three general and teaching hospitals with clinically suspected pulmonary embolism underwent sequential noninvasive testing. Clinical probability was assessed by a prediction rule combined with implicit judgment. All patients were followed for 3 months. RESULTS: A normal D-dimer level (<500 microg/L by a rapid enzyme-linked immunosorbent assay) ruled out venous thromboembolism in 280 patients (29%), and finding a deep vein thrombosis by ultrasonography established the diagnosis in 92 patients (9.5%). Helical CT was required in only 593 patients (61%) and showed pulmonary embolism in 124 patients (12.8%). Pulmonary embolism was considered ruled out in the 450 patients (46.6%) with a negative ultrasound and CT scan and a low-to-intermediate clinical probability. The 8 patients with a negative ultrasound and CT scan despite a high clinical probability proceeded to pulmonary angiography (positive: 2; negative: 6). Helical CT was inconclusive in 11 patients (pulmonary embolism: 4; no pulmonary embolism: 7). The overall prevalence of pulmonary embolism was 23%. Patients classified as not having pulmonary embolism were not anticoagulated during follow-up and had a 3-month thromboembolic risk of 1.0% (95% confidence interval: 0.5% to 2.1%). CONCLUSION: A noninvasive diagnostic strategy combining clinical assessment, D-dimer measurement, ultrasonography, and helical CT yielded a diagnosis in 99% of outpatients suspected of pulmonary embolism, and appeared to be safe, provided that CT was combined with ultrasonography to rule out the disease.

Ambulatory blood pressure measurement and antihypertensive therapy.

The traditional basis for assessing the effect of antihypertensive therapy is the blood pressure reading taken by a physician. However, several recent trials have been designed to evaluate the blood pressure lowering effect of various therapeutic agents during the patients' normal daytime activities, using a portable, semi-automatic blood pressure recorder. The results have shown that in a given patient, blood pressure measured at the physician's office often differs greatly from that prevailing during the rest of the day. This is true both in treated and untreated hypertensive patients. The difference between office and ambulatory recorded pressures cannot be predicted from blood pressure levels measured by the physician. Therefore, a prospective study was carried out in patients with diastolic blood pressures that were uncontrolled at the physician's office despite antihypertensive therapy. The purpose was to evaluate the response of recorded ambulatory blood pressure to treatment adjustments aimed at reducing office blood pressure below a pre-set target level. Only patients with high ambulatory blood pressures at the outset appeared to benefit from further changes in therapy. Thus, ambulatory blood pressure monitoring can be used to identify those patients who remain hypertensive only when facing the physician, despite antihypertensive therapy. Ambulatory monitoring could thus help to evaluate the efficacy of antihypertensive therapy and allow individual treatment.

Automatic measurement of key ski jumping phases and temporal events with a wearable system.

We propose a new method, based on inertial sensors, to automatically measure at high frequency the durations of the main phases of ski jumping (i.e. take-off release, take-off, and early flight). The kinematics of the ski jumping movement were recorded by four inertial sensors, attached to the thigh and shank of junior athletes, for 40 jumps performed during indoor conditions and 36 jumps in field conditions. An algorithm was designed to detect temporal events from the recorded signals and to estimate the duration of each phase. These durations were evaluated against a reference camera-based motion capture system and by trainers conducting video observations. The precision for the take-off release and take-off durations (indoor < 39 ms, outdoor = 27 ms) can be considered technically valid for performance assessment. The errors for early flight duration (indoor = 22 ms, outdoor = 119 ms) were comparable to the trainers' variability and should be interpreted with caution. No significant changes in the error were noted between indoor and outdoor conditions, and individual jumping technique did not influence the error of take-off release and take-off. Therefore, the proposed system can provide valuable information for performance evaluation of ski jumpers during training sessions.

Determination of displacement, stress- and strain-distribution in the human heart: a FE-model on the basis of MR imaging.

The determination of characteristic cardiac parameters, such as displacement, stress and strain distribution are essential for an understanding of the mechanics of the heart. The calculation of these parameters has been limited until recently by the use of idealised mathematical representations of biventricular geometries and by applying simple material laws. On the basis of 20 short axis heart slices and in consideration of linear and nonlinear material behaviour we have developed a FE model with about 100,000 degrees of freedom. Marching Cubes and Phong's incremental shading technique were used to visualise the three dimensional geometry. In a quasistatic FE analysis continuous distribution of regional stress and strain corresponding to the endsystolic state were calculated. Substantial regional variation of the Von Mises stress and the total strain energy were observed at all levels of the heart model. The results of both the linear elastic model and the model with a nonlinear material description (Mooney-Rivlin) were compared. While the stress distribution and peak stress values were found to be comparable, the displacement vectors obtained with the nonlinear model were generally higher in comparison with the linear elastic case indicating the need to include nonlinear effects.

Adolescent Drug Abuse Diagnosis (ADAD) vs. Health of Nation Outcome Scale for Children and Adolescents (HoNOSCA) in clinical outcome measurement.

BACKGROUND: The Adolescent Drug Abuse Diagnosis (ADAD) and Health of Nation Outcome Scales for Children and Adolescents (HoNOSCA) are both measures of outcome for adolescent mental health services. AIMS: To compare the ADAD with HoNOSCA; to examine their clinical usefulness. METHODS: Comparison of the ADAD and HoNOSCA outcome measures of 20 adolescents attending a psychiatric day care unit. RESULTS: ADAD change was positively correlated with HoNOSCA change. HoNOSCA assesses the clinic's day-care programme more positively than the ADAD. The ADAD detects a group for which the mean score remains unchanged whereas HoNOSCA does not. CONCLUSIONS: A good convergent validity emerges between the two assessment tools. The ADAD allows an evidence-based assessment and generally enables a better subject discrimination than HoNOSCA. HoNOSCA gives a less refined evaluation but is more economic in time and possibly more sensitive to change. Both assessment tools give useful information and enabled the Day-care Unit for Adolescents to rethink the process of care and of outcome, which benefited both the institution and the patients.

Measurement of 13CO2 in expired air as an index of compliance to a high carbohydrate diet naturally enriched in 13C.

The aim of this study was to determine whether breath 13CO2 measurements could be used to assess the compliance to a diet containing carbohydrates naturally enriched in 13C. The study was divided into two periods: Period 1 (baseline of 4 days) with low 13C/12C ratio carbohydrates. Period 2 (5 days) isocaloric diet with a high 13C/12C ratio (corn, cane sugar, pineapple, millet) carbohydrates. Measurements were made of respiratory gas exchange by indirect calorimetry, urinary nitrogen excretion and breath 13CO2 every morning in post-absorptive conditions, both in resting state and during a 45-min low intensity exercise (walking on a treadmill). The subjects were 10 healthy lean women (BMI 20.4 +/- 1.7 kg/m2, % body fat 24.4 +/- 1.3%), the 13C enrichment of oxidized carbohydrate and breath 13CO2 were compared to the enrichment of exogenous dietary carbohydrates. At rest the enrichment of oxidized carbohydrate increased significantly after one day of 13C carbohydrate enriched diet and reached a steady value (103 +/- 16%) similar to the enrichment of exogenous carbohydrates. During exercise, the 13C enrichment of oxidized carbohydrate remained significantly lower (68 +/- 17%) than that of dietary carbohydrates. The compliance to a diet with a high content of carbohydrates naturally enriched in 13C may be assessed from the measurement of breath 13CO2 enrichment combined with respiratory gas exchange in resting, postabsorptive conditions.

Relations of the job demands-control-support model of job strain with personality attributes : a cross-cultural study in Switzerland and South Africa

Among the various work stress models, one of the most popular to date is the job demands-­‐control (JDC) model developed by Karasek (1979), which postulates that work-­‐related strain will be the highest under work conditions characterized by high demands and low autonomy. The absence of social support at work will further increase negative outcomes. However, this model does not apply equally to all individuals and to all cultures. In the following studies, we assessed work characteristics, personality traits, culture-­‐driven individual attributes, and work-­‐related health outcomes, through the administration of questionnaires. The samples consist of Swiss (n = 622) and South African (n = 879) service-­‐oriented employees (from health, finance, education and commerce sectors) and aged from 18 to 65 years old. Results generally confirm the universal contribution of high psychological demands, low decision latitude and low supervisor support at work, as well as high neuroticism predict the worse health outcomes among employees in both countries. Furthermore, low neuroticism plays a moderating role between psychological demands and burnout, while high openness and high conscientiousness each play a moderating role between decision latitude and burnout in South Africa. Results also reveal that culture-­‐driven individual attributes play a role in both countries, but in a unique manner and according to the ethnic group of belonging. Given that organizations are increasingly characterized with multicultural employees as well as increasingly adverse and complex job conditions, our results help in identifying more updated and refined dynamics that are key between the employee and the work environment in today's context. -- L'un des modèles sur le stress au travail des plus répandus est celui développé par Karasek (1979), qui postule qu'une mauvaise santé chez les employés résulte d'une combinaison de demandes psychologiques élevées, d'une latitude décisionnelle faible et de l'absence de soutien social au travail. Néanmoins, ce modèle ne s'applique pas de façon équivalente chez tous les individus et dans toutes les cultures. Dans les études présentées, nous avons mesuré les caractéristiques de travail, les traits de personnalité, les traits culturels et les effets lies à la santé à l'aide de questionnaires. L'échantillon provient de la Suisse (n = 622) et de l'Afrique du Sud (n = 879) et comprend des employés de domaines divers en lien avec le service (notamment des secteurs de la santé, finance, éducation et commerce) tous âgés entre 18 et 65 ans. Les résultats confirment l'universalité des effets directs des demandes au travail, la latitude décisionnelle faible, le soutien social faible provenant du supérieur hiérarchique, ainsi que le névrosisme élevé qui contribuent à un niveau de santé faible au travail, et ce, dans les deux pays. De plus, un niveau faible de névrosisme a un effet de modération entre les demandes au travail et l'épuisement professionnel, alors que l'ouverture élevée et le caractère consciencieux élevé modèrent la relation entre la latitude décisionnelle et l'épuisement professionnel en Afrique du Sud. Nous avons aussi trouvé que les traits culturels jouent un rôle dans les deux pays, mais de façon unique et en fonction du groupe ethnique d'appartenance. Sachant que les organisations sont de plus en plus caractérisées par des employés d'origine ethnique variées, et que les conditions de travail se complexifient, nos résultats contribuent à mieux comprendre les dynamiques entre l'employé et l'environnement de travail contemporain. personnalité, différences individuelles, comparaisons culturelles, culture, stress au travail, épuisement professionnel, santé des employés.

Measurement of parent satisfaction in french-speaking PICUs: a need for translation and cultural adaptation of the empathic questionnaire

Background and aims: Family-centred care is an expected standard in PICU and parent reported outcomes are rarely measured. The Dutch validated EMPATHIC questionnaire provides accurate measures of parental perceptions of family-centred care in PICU. A French version would provide an important resource for quality control and benchmarking with other PICUs. The study aimed to translate and to assess the French cultural adaptation of the EMPATHIC questionnaire. Methods: In September 2012, following approval from the developer, translation and cultural adaptation were performed using a structured method (Wild et al. 2005). This included forward-backward translation and reconciliation by an official translator, harmonization assessed by the research team, and cognitive debriefing with the target users' population. In this last step, a convenience sample of parents with PICU experience assessed the comprehensibility and cultural relevance of the 65-item French EMPATHIC questionnaire. The PICUs in Lausanne, Switzerland and Lille, France participated. Results: Seventeen parents, including 13 French native and 4 French as second language speakers, tested the cognitive equivalence and cultural relevance of the French EMPATHIC questionnaire. The mean agreement for comprehensibility of all 65 items reached 90.2%. Three items fell below the cut-off 80% agreement and were revised for inclusion in the final French version. Conclusions: The translation and the cultural adaptation permitted to highlight a few cultural differences that did not interfere with the main construct of the EMPATHIC questionnaire. Reliability and validity testing with a new sample of parents is needed to strengthen the psychometric properties of the French EMPATHIC questionnaire.

In vivo measurement of tissue oxygenation by time-resolved luminescence spectroscopy: advantageous properties of dichlorotris(1, 10-phenanthroline)-ruthenium(II) hydrate.

Measuring tissue oxygenation in vivo is of interest in fundamental biological as well as medical applications. One minimally invasive approach to assess the oxygen partial pressure in tissue (pO2) is to measure the oxygen-dependent luminescence lifetime of molecular probes. The relation between tissue pO2 and the probes' luminescence lifetime is governed by the Stern-Volmer equation. Unfortunately, virtually all oxygen-sensitive probes based on this principle induce some degree of phototoxicity. For that reason, we studied the oxygen sensitivity and phototoxicity of dichlorotris(1, 10-phenanthroline)-ruthenium(II) hydrate [Ru(Phen)] using a dedicated optical fiber-based, time-resolved spectrometer in the chicken embryo chorioallantoic membrane. We demonstrated that, after intravenous injection, Ru(Phen)'s luminescence lifetime presents an easily detectable pO2 dependence at a low drug dose (1 mg∕kg) and low fluence (120 mJ∕cm2 at 470 nm). The phototoxic threshold was found to be at 10 J∕cm2 with the same wavelength and drug dose, i.e., about two orders of magnitude larger than the fluence necessary to perform a pO2 measurement. Finally, an illustrative application of this pO2 measurement approach in a hypoxic tumor environment is presented.

Positive Torsional Strain Causes the Formation of a Four-Way Junction at Replication Forks.

Research by L. Postow, C. Ullsperger, R.W. Keller, C. Bustamante, A.V. Vologodskii, and N.R. Cozzarelli, J. Biol. Chem. 2001, 276, 2790 Condensation and commentary by Alexander Bucka and Andrzej Stasiak, Universite ´ de Lausanne, Switzerland Purpose of the Study To demonstrate that positive torsional strain generated during DNA replication can lead to reversals of replication forks and, consequently can result in the formation of four-way DNA junctions

Simultaneous cell morphometry and refractive index measurement with dual-wavelength digital holographic microscopy and dye-enhanced dispersion of perfusion medium.

Digital holographic microscopy (DHM) allows optical-path-difference (OPD) measurements with nanometric accuracy. OPD induced by transparent cells depends on both the refractive index (RI) of cells and their morphology. This Letter presents a dual-wavelength DHM that allows us to separately measure both the RI and the cellular thickness by exploiting an enhanced dispersion of the perfusion medium achieved by the utilization of an extracellular dye. The two wavelengths are chosen in the vicinity of the absorption peak of the dye, where the absorption is accompanied by a significant variation of the RI as a function of the wavelength.

Prognostic accuracy of cerebral blood flow measurement by perfusion computed tomography, at the time of emergency room admission, in acute stroke patients.

The purpose of this study was to determine the prognostic accuracy of perfusion computed tomography (CT), performed at the time of emergency room admission, in acute stroke patients. Accuracy was determined by comparison of perfusion CT with delayed magnetic resonance (MR) and by monitoring the evolution of each patient's clinical condition. Twenty-two acute stroke patients underwent perfusion CT covering four contiguous 10mm slices on admission, as well as delayed MR, performed after a median interval of 3 days after emergency room admission. Eight were treated with thrombolytic agents. Infarct size on the admission perfusion CT was compared with that on the delayed diffusion-weighted (DWI)-MR, chosen as the gold standard. Delayed magnetic resonance angiography and perfusion-weighted MR were used to detect recanalization. A potential recuperation ratio, defined as PRR = penumbra size/(penumbra size + infarct size) on the admission perfusion CT, was compared with the evolution in each patient's clinical condition, defined by the National Institutes of Health Stroke Scale (NIHSS). In the 8 cases with arterial recanalization, the size of the cerebral infarct on the delayed DWI-MR was larger than or equal to that of the infarct on the admission perfusion CT, but smaller than or equal to that of the ischemic lesion on the admission perfusion CT; and the observed improvement in the NIHSS correlated with the PRR (correlation coefficient = 0.833). In the 14 cases with persistent arterial occlusion, infarct size on the delayed DWI-MR correlated with ischemic lesion size on the admission perfusion CT (r = 0.958). In all 22 patients, the admission NIHSS correlated with the size of the ischemic area on the admission perfusion CT (r = 0.627). Based on these findings, we conclude that perfusion CT allows the accurate prediction of the final infarct size and the evaluation of clinical prognosis for acute stroke patients at the time of emergency evaluation. It may also provide information about the extent of the penumbra. Perfusion CT could therefore be a valuable tool in the early management of acute stroke patients.