Consideration of unmeasured micropollutants released from WWTP for potential impact estimations.

During wastewater treatment, micropollutants are only partly eliminated and may present a risk for human health and aquatic ecosystems. The potential impacts these substances may have are currently underestimated due to the lack in available concentrations that lie below the limit of quantification (LOQ) for an important set of micropollutants. Here, the potential impacts due to 261 organic micropollutants on human health and aquatic environments were investigated at the scale of France. Even with concentrations below the LOQ, certain micropollutants were found to have a significant potential impact. For unmeasured concentrations, a global concentration distribution built from several datasets with different LOQ was used. By disregarding the unmeasured micropollutants, the potential impacts have been underestimated by >300 % on both human health and aquatic environments. Certain substances, such as hydrazine, endrin, or 2,3,7,8-TetraCDD, could lead to very strong potential impacts, even with unmeasured concentration levels. Moreover, the usual convention of LOQ/2 to replace unmeasured concentrations also appeared to overestimate the potential impact. The present work can be adapted to any other compartment or geographical context.

Short communication: Little change takes place in Camembert-type cheese water activities throughout ripening in terms of relative humidity and salt.

Water activity (a(w)) affects the growth and activity of ripening microorganisms. Moreover, it is generally accepted that a(w) depends on relative humidity (RH) and salt content; these 3 variables were usually measured on a given day in a cheese without the microorganism layer and without accounting for a distinction between the rind, the underrind, and the core. However, a(w) dynamics have never been thoroughly studied throughout cheese ripening. Experimental Camembert cheeses were ripened under controlled and aseptic conditions (temperature, gaseous atmosphere, and RH) for 14 d. In this study, only RH was varied. Samples were taken from the cheese (microorganism layer)-air interface, the rind, and the core. The aw of the cheese-air interface did not change over ripening when RH varied between 91 and 92% or between 97 and 98%. However, on d 5, we observed a small but significant increase in a(w), which coincided with the beginning of growth of Penicillium camemberti mycelia. After d 3, no significant differences were found between the a(w) of the cheese-air interface, the rind, and the core. From d 0 to 3, cheese rind a(w) increased from 0.94 to 0.97, which was probably due to the diffusion of salt from the rind to the core: NaCl content in the rind decreased from 3.7 to 1.6% and NaCl content in the core increased from 0.0 to 1.6%. Nevertheless, aw did not significantly vary in the core, raising questions about the real effect of salt on a(w).

Modeling of Camembert-type cheese mass loss in a ripening chamber: main biological and physical phenomena.

A model of the mass loss of Camembert-type cheese was established with data obtained from 2 experimental ripening trials carried out in 2 pilot ripening chambers. During these experiments, a cheese was continuously weighed and the relative humidity, temperature, oxygen, and carbon dioxide concentrations in the ripening chamber were recorded online. The aim was to establish a simple but accurate model that would predict cheese mass changes according to available online measurements. The main hypotheses were that 1) the cheese water activity was constant during ripening, 2) the respiratory activity of the microflora played a major role by inducing heat production, combined with important water evaporation, 3) the temperature gradient existing inside the cheese was negligible, and the limiting phenomenon was the convective transfer. The water activity and the specific heat of the cheeses were assessed by offline measurements. The others parameters in the model were obtained from the literature. This dynamic model was built with 2 state variables: the cheese mass and the surface temperature of the cheese. In this way, only the heat transfer coefficient had to be fitted, and it was strongly determined by the airflow characteristics close to the cheeses. Model efficiency was illustrated by comparing the estimated and measured mass and the mass loss rate for the 2 studied runs; the relative errors were less than 1.9 and 3.2% for the mass loss and the mass loss rate, respectively. The dynamic effects of special events, such as room defrosting or changes in chamber relative humidity, were well described by the model, especially in terms of kinetics (mass loss rates).

A model describing Debaryomyces hansenii growth and substrate consumption during a smear soft cheese deacidification and ripening.

A mechanistic model for Debaryomyces hansenii growth and substrate consumption, lactose conversion into lactate by lactic acid bacteria, as well as lactose and lactate transfer from the core toward the rind was established. The model described the first step (14 d) of the ripening of a smear soft cheese and included the effects of temperature and relative humidity of the ripening chamber on the kinetic parameters. Experimental data were collected from experiments carried out in an aseptic pilot scale ripening chamber under 9 different combinations of temperature (8, 12, and 16 degrees C) and relative humidity (85, 93, and 99%) according to a complete experimental design. The model considered the cheese as a system with 2 compartments (rind and core) and included 5 state evolution equations and 16 parameters. The model succeeded in predicting D. hansenii growth and lactose and lactate concentrations during the first step of ripening (curd deacidification) in core and rind. The nonlinear data-fitting method allowed the determination of tight confidence intervals for the model parameters. The residual standard error (RSE) between model predictions and experimental data was close to the experimental standard deviation between repeated experiments.

An integrated system to remote monitor and control anaerobic wastewater treatment plants through the internet.

The TELEMAC project brings new methodologies from the Information and Science Technologies field to the world of water treatment. TELEMAC offers an advanced remote management system which adapts to most of the anaerobic wastewater treatment plants that do not benefit from a local expert in wastewater treatment. The TELEMAC system takes advantage of new sensors to better monitor the process dynamics and to run automatic controllers that stabilise the treatment plant, meet the depollution requirements and provide a biogas quality suitable for cogeneration. If the automatic system detects a failure which cannot be solved automatically or locally by a technician, then an expert from the TELEMAC Control Centre is contacted via the internet and manages the problem.

[Functional anatomy of the central nervous system]. / Anatomie fonctionnelle du système nerveux central.

The central nervous system (CNS) has a particular regional functional anatomy. The morphological support of cognitive functions can now be depicted using functional imaging. Lesions of the central nervous system may be responsible of specific symptoms based on their location. Current neuroimaging techniques are able to show and locate precisely macroscopic lesions. Therefore, the knowledge of functional anatomy of the central nervous system is useful to link clinical disorders to symptomatic lesions. Using radio-clinical cases, we present the functional neuro-anatomy related to common cognitive impairments.

MRI findings in a case of a superficial siderosis associated with an ependymoma.

We present the imaging findings of superficial siderosis of the central nervous system associated with an ependymoma of the posterior fossa in a patient who presented with progressive bilateral sensorineural hearing loss and cerebellar ataxia. The ependymoma was a homogeneous well-defined mass of the fourth ventricle without hydrocephalus. Secondary siderosis due to chronic bleeding from the ependymoma appeared as linear hypointensity delineating the surface of the cortex, thin and subtle on spin-echo T2-weighted images, thick and obvious on gradient-echo T2-weighted images.

Preparation and implementation of seven ecological compensation plans for Dutch highways.

First-generation compensation plans (CPs) for Dutch highway projects have been evaluated with respect to implementation of the compensation principle (1993), which aims to counterbalance the adverse ecological impacts of large-scale development projects. Decision-making on the seven projects took place between 1993 and 1995. Specifically, we considered: (a) the processes employed to prepare and implement the compensation plans; (b) the methods used to identify, plan, and execute the compensation measures; and (c) the results yielded by these methods. We conclude that the CPs were prepared fairly uniformly, particularly in terms of the processes and methodologies used to derive compensation measures. Five of the seven CPs had become operational by 2001 and initial experience is now being gained on land acquisition and transfer of compensation sites to nature conservation trusts. Further progress of CPs is likely to be seriously hampered by growing demand for land for development in general and associated increases in real estate prices. Several problems are addressed and recommendations made with respect to: (a) developing a legal basis for the compensation principle; (b) the relationship with re-allotment projects; (c) estimation of compensation costs; (d) an annual bias of CP budgets to account for rising costs; (e) contingency measures; and (f) criteria for CP (ex-post) evaluation.

[Transient neurological manifestations disclosing spontaneous acute cervical epidural hematoma]. / Manifestations neurologiques transitoires révélatrices d'hématomes épiduraux cervicaux aigus spontanés.

Spontaneous cervical epidural hematomas are uncommon lesions that usually produce permanent neurological deficit unless there is early surgical decompression. They are now well-recognized by scan X and especially by sagittal MRI of the spine. We describe 2 patients, a 24 year-old man and a 79 year-old woman with no previous history of trauma who were admitted in emergency for a sudden weakness of limbs, respectively a tetraplegia and a right hemiplegia. Both patients complained of inaugural and acute neck pain. Motor deficit completely resolved in few hours and MRI of the spine showed on T1 a signal isointense, extending respectively from C3 to C6 and C5 to C7, consistent with an hematoma. Laboratory data and angiography were normal. Surgery was recused. Neck pain lasted about a week. Follow-up MRI, in one case, was normal two months later. Cervical epidural hematomas revealed by transient neurological findings that completely and permanently resolved are exceptional. They could mimic ischemic myelopathy and should be considered in the differential diagnosis of other painful vascular conditions like symptomatic vertebral dissection to avoid inappropriate anticoagulation. Conservative management in these cases may be proposed if spontaneous neurological resolution is confirmed by MRI.

[Arachnoid cyst of the temporal fossa. Subdural hematoma. Contribution of MRI]. / Kyste arachnoïdien de la fosse temporale. Hématome sous-dural. Apport de l'IRM.

A 20-year old man presented with an arachnoid cyst of the middle fossa and a subdural hematoma (SDH). An intra-cystic hemorrhage masked the presence of the SDH on CT. MRI demonstrated a communication between cyst and SDH. The mechanism of SDH formation is discussed.

MR imaging of spinal cord arteriovenous malformations at 0.5 T: study of 34 cases.

Thirty-four patients with angiographically proved arteriovenous malformations of the spinal cord were studied between May 1986 and July 1987. Examinations were performed on a CGR 5000 Magniscan 0.5-T scanner with a surface coil in all cases, and multislices in both T1- and T2-weighted sequences were obtained in sagittal and axial planes. The results showed that MR can accurately diagnose all cases of intramedullary arteriovenous malformations, since transverse images were able to precisely locate the nidus within the spinal cord. Other types of spinal cord arteriovenous malformations were also studied (perimedullary fistulae and dural arteriovenous fistula), and the findings confirmed the value of MR in the characterization of these lesions as well.

[Lumbar phelbography without catheterization. Technic, indications and results in the diagnosis of intervertebral disk herniation]. / La phlébographie lombaire sans cathétérisme. Technique, indications, résultats dans le diagnostic de la hernie discale.

The authors present a new method of lumbar phlebology without catheterism by direct venous puncture of the femoral veins. An analysis of 300 contrast tests maked it possible to identify different types of pathological images characterized by disappearance and displacement of epidural veins corresponding as a rule to discal hernia when the uncharacteristic shadowy images do not allow one to make a precise conclusion or to determine whether an operation is needed. With equal reliability (96 percent), lumbar phlebography without catheterism is, by its simplicity and harmlessness and the absence of minor and major venous complications, preferable to phlebography by catheterism. Carried out in all subjects, whatever their age, without special precautions, it seems to us to now be the most desirable test to be used in the radiological investigation of lumbar discal hernias.

[Pleural manifestations of secondary monoclonal dysproteinemia (apropos of 4 cases)]. / Manifestations pleurales au cours de dysprotéinémies monoclonales secondaires (à propos de 4 observations).

A pleural effusion with monoclonal macroglobulinemia is not unusual outside Kahler and Waldenström diseases which are the two commonest. It can occur in lymphoid leucosis with plasma concentration peaks, where surface immunoglobulins play an important part, and in some epithelial cancers. As in primitive macroglobulinemia the plasma concentration peak corresponds to pleural globulin modifications. But it seems that, whatever the variations of pathological immunoglobulins, the pleural lymphocytes, predominant in the effusion, play an active part due to various etiological stimulations.