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« De rechef la reprint par le bras disant que : Par la mort et vertu Dieu ! il l’en mèneroit ou il tueroit elle, son maître et sa maistresse ; et de faict l’en menist par force contre son gré et volunté […] et estant au delà du mulin […] luy dict : Entre en ceste haye ! […] Mort Dieu, entre ! poussant par force la mist en ladite haye et estant en icelle luy dict : Couche toy ! ce qu’elle ne voulust faire ; ce néantmoins […] par force la couchist par terre et combien que de son pouvoir se deff...

Metal and redox homeostasis in cyanobacteria is tightly controlled to preserve the photosynthetic machinery from mismetallation and minimize cell damage. This control is mainly taken by FUR (ferric uptake regulation) proteins. FurC works as the PerR (peroxide response) paralog in Anabaena sp. PCC7120. Despite its importance, this regulator remained poorly characterized. Although FurC lacks the typical CXXC motifs present in FUR proteins, it contains a tightly bound zinc per subunit. FurC: Zn stoichiometrically binds zinc and manganese in a second site, manganese being more efficient in the binding of FurC: Zn to its DNA target PprxA. Oligomerization analyses of FurC: Zn evidence the occurrence of different aggregates ranging from dimers to octamers. Notably, intermolecular disulfide bonds are not involved in FurC: Zn dimerization, dimer being the most reduced form of the protein. Oligomerization of dimers occurs upon oxidation of thiols by H2O2 or diamide and can be reversed by 1,4-Dithiothreitol (DTT). Irreversible inactivation of the regulator occurs by metal catalyzed oxidation promoted by ferrous iron. However, inactivation upon oxidation with H2O2 in the absence of iron was reverted by addition of DTT. Comparison of models for FurC: Zn dimers and tetramers obtained using AlphaFold Colab and SWISS-MODEL allowed to infer the residues forming both metal-binding sites and to propose the involvement of Cys86 in reversible tetramer formation. Our results decipher the existence of two levels of inactivation of FurC: Zn of Anabaena sp. PCC7120, a reversible one through disulfide-formed FurC: Zn tetramers and the irreversible metal catalyzed oxidation. This additional reversible regulation may be specific of cyanobacteria.

The paper provides a brief overview on the state of the art of the numerical modeling in present system thermal-hydraulic codes in the framework of the Forum & Network of System Thermal-Hydraulics Codes in Nuclear Reactor Thermal-Hydraulics (FONESYS). FONESYS is a network among code developers who share the common objective to strengthen current technology and to bring technical argumentation against possible disbelief in SYS-TH codes. The aim of the FONESYS network is to highlight the capabilities and the robustness as well as the limitations of current SYS-TH codes to predict the main phenomena during transient scenarios in nuclear reactors for safety issues. This objective will be achieved primarily through the development of a strategy that aims to identify the key aspects for the improvement of SYS-TH codes and then establish a work program regarding actions to be taken to provide an answer to the needs listed in the Road Map of FONESYS network. In this regard, key topics, like the hyperbolicity, the numerical methods and some closure laws with particular reference to the modeling of some interfacial forces in the current SYS-TH codes, have been treated by the FONESYS network and are summarized in this paper.

Some aspects of large break LOCA analysis (steam binding, oscillatory reflooding, top-down reflooding) are expected to be improved in advanced system codes from more detailed description of flows by adding a third field for droplets. The future system code CATHARE-3 is under development by CEA and supported by EDF, AREVA-NP and IRSN in the frame of the NEPTUNE project and this paper shows some preliminary results obtained in reflooding conditions. A three-field model has been implemented, including vapor, continuous liquid and liquid droplet fields. This model features a set of nine equations of mass, momentum and energy balance. Such a model allows a more detailed description of the droplet transportation from core to steam generator, while countercurrent flow of continuous liquid is allowed. Code assessment against reflooding experiments in a rod bundle is presented, using 1D meshing of the bundle. Comparisons of CATHARE-3 simulations against data series from PERICLES and RBHT full scale experiments show satisfactory results. Quench front motions are well predicted, as well as clad temperatures in most of the tested runs. The BETHSY 6.7C Integral Effect Test simulating the gravity driven reflooding process in a scaled PWR circuit is then compared to CATHARE-3 simulation. The three-field model is applied in several parts of the circuit: core, upper plenum, hot leg and steam generator, represented by either 1D or 3D modules, while the classic six-equation model is used in the other parts of the loop. An analysis of these first results is presented and future work is defined for improving the droplet behavior simulation in both the upper plenum and the hot legs.

The WATLON water experiment about fluid mixing in a tee pipe is calculated with a finite element volume method and a large eddy simulation (LES) approach, with the TRIO-U code. Its unstructured tet...

The purpose of this article is to present briefly the project called Forum & Network of System Thermal-Hydraulics Codes in Nuclear Reactor Thermal-Hydraulics (FONESYS), its participants, the motivation for the project, its main targets and working modalities. System Thermal-Hydraulics (SYS-TH) codes, also as part of the Best Estimate Plus Uncertainty (BEPU) approaches, are expected to achieve a more-and-more relevant role in nuclear reactor technology, safety and design. Namely, the number of code-users can easily be predicted to increase in the countries where nuclear technology is exploited. Thus, the idea of establishing a forum and a network among the code developers and with possible extension to code users has started to have major importance and value. In this framework the FONESYS initiative has been created. The main targets of FONESYS are: • To promote the use of SYS-TH Codes and the application of the BEPU approaches. • To establish acceptable and recognized procedures and thresholds for Verification and Validation (V&V). • To create a common ground for discussing envisaged improvements in various areas, including user-interface, and the connection with other numerical tools, including Computational Fluid Dynamics (CFD) Codes.

Resume Introduction Nous rapportons le cas d’une jeune femme presentant une dyspnee d’exercice. Dans ses antecedents chirurgicaux, on notait une correction neonatale d’un double arc aortique. Au repos, l’analyse de sa courbe debit/volume revelait une limitation moderee du debit de pointe sans plateau expiratoire. La capacite d’exercice etait limitee par la survenue brutale lors des 2 derniers paliers de l’epreuve d’une dyspnee inspiratoire avec tachypnee. Pendant la recuperation, on ne mettait pas en evidence de bronchospasme. Cas clinique Devant ce tableau, nous avons suspecte une obstruction des voies aeriennes superieures et la bronchoscopie realisee a effectivement mis en evidence une compression tracheale a 50% de la normale. Le scanner thoracique avec reconstruction tridimensionnelle a permis de visualiser la trachee enserree entre 2 branches aortiques. Afin d’affirmer que la compression tracheale augmentait au cours de l’exercice, nous avons realise un test de « handgrip », induisant une stimulation sympathique, qui a reproduit la dyspnee inspiratoire et a provoque une diminution des debits inspiratoires. Conclusion Nous avons ainsi demontre que l’accentuation de la compression tracheale provoquant la limitation des debits aeriens a l’exercice etait due a l’augmentation de la pression dans l’aorte et non a celle du debit ventile.

We will try to present herein the main issues of our investigation in numerical methods for two-phase flow modeling, within the framework of the NEPTUNE project, which benefits from both contributions of CEA and EDF. These may be recast in five work packages. The first two are devoted to the mathematical and numerical modeling of two-phase flows with interfaces and the two-fluid two pressure approach. This in particular includes investigation of relaxation methods in order to establish correct links with standard two-fluid models, which are the core of the third work package. Computations of the interaction of shock waves with bubbles will be presented. Some new results concerning two-fluid and three-field flow modeling will also be briefly presented. Part of the work in the third work package concerns benchmarking, and comparison with several hyperbolic solvers, but also improvement of numerical treatment of source terms, multi-field models and suitable boundary conditions. The fourth one, which deals with the interfacial coupling of codes, is probably the most important one since it requires connecting all models together. Since little attention has been paid to this crucial point, part of the focus will be given in this paper on the coupling of equations of state, one-dimensional and three-dimensional codes, porous approach and free medium approach, but also on ongoing work concerning relaxed and unrelaxed hyperbolic two-phase flow models. The fifth work package gathers all classical contributions in numerical methods, including: recent applications of fictitious domain methods ; preconditioning of so-called “low Mach number” two-phase flows (with applications to the motion of rising bubbles in water) ; parallel and multigrid techniques (with applications to steam generators in nuclear power plants) ; Finite Volume Element methods (with applications to the standard two-fluid models) ; construction and validation of new exact or approximate Riemann solvers (in order to cope with vanishing phases). The latter five obviously aim at improving accuracy, stability and also at reducing CPU time. A few examples will enable to highlight the main advantages and possible drawbacks of these new developments, and the impact of the current and future increasing computational facilities. Main past achievements, and key points of current and future work on all these issues will be discussed. All available references will be given in order to help the reader getting a more accurate insight on these various contributions. The whole has clearly benefited from contributions of several PhD students : Thomas Fortin, Vincent Guillemaud, Olivier Hurisse, Angelo Muronne, Isabelle Ramiere, Jean-Michel Rovarch and Nicolas Seguin.

Forecasting pollination would help allergists to establish an appropriate prevention for allergic patients. Previous studies have related meteorological variables to airborne pollen counts; patients suffer allergy episodes before the peak of pollen is reached. A 10-year study was done in Saint-Etienne (France) by a multi-disciplinary team (medical doctors, meteorologists, plant biologists). The frequency distribution of patients with pollinosis was obtained from mid-January to August every year. The meteorological station recorded the temperatures daily; pollen counts were obtained with a pollen trap. The maturation stages of trees (ash, birch) and graminaceae (dactyl and meadow grass) were followed by weekly sampling and provided the exact date of pollination. Mathematical models were built to predict the developmental stages of plant growth and the values were compared with the exact dates obtained every year. The frequency distribution of allergic patients was either mono or biphasic according to the evolution of daily temperatures. The maximum peak of patients always preceded the peak of graminaceae over the 10-year period. Different models were found to adequately predict the pollination dates: a Q 10-based algorithm best described the pollination date of trees; a weighted Q 10 algorithm best reflected the pollination of graminaceae.

This article presents the guiding principles of the architecture of Trio U, a new genera- tion of software for thermohydraulic calculations. Trio U is designed to serve as a thermohydraulic development platform. Its basic conception is object-oriented and it is written in C++. The article demonstrates how this type of design enables an open, modular software architecture.

National audience; Pour tenter d'enrayer le phénomène des troublesmusculo-squelettiques (TMS), la psychologie du travail etl'ergonomie sont à la recherche d'approches méthodologiquesinnovantes et efficaces.

The increased sympathetic activation that occurs in obstructive sleep apnoea (OSA) may play an important role in associated morbidity. We investigated the effect of long-term (3 month) nasal continuous positive airway pressure (CPAP) on the autonomic nervous system assessed by heart rate variability (HRV). Fourteen patients (12 men), mean age 61.4 +/- 8.1 years, with OSA underwent continuous synchronized electrocardiographic and polysomnographic monitoring. The apnoea/hypopnoea index (AHI) decreased from 50.6 +/- 13.7 to 2.2 +/- 2.5 events h-1 after CPAP. HRV analysis showed significant decreases in low frequency (LF; from 7.12 +/- 1.06 to 6.22 +/- 1.18 ln ms2 Hz-1; P < 0.001), high frequency (HF; from 5.91 +/- 0.87 to 5.62 +/- 0.92 ln ms2 Hz-1; P < 0.05) and LF/HF (from 1.21 +/- 0.12 to 1.11 +/- 0.15 ln ms2 Hz-1; P < 0.001) when the patients were asleep. The decrease in LF/HF was prolonged into the daytime (from 1.33 +/- 0.22 to 1.24 +/- 0.21 ln ms2 Hz-1; P < 0.001). Treatment of OSA by CPAP significantly reduced the parameters of cardiac sympathetic tone, a favourable effect.

This study investigated 22 patients with histologically proven primary bronchial carcinoids and in particular the relationship between assessment parameters and survival. In each patient, age, sex, smoking habits, mode of presentation, results of diagnostic investigations, methods of treatment and pathological examination of resected specimens were recorded. Follow-up was possible in all patients for at least 5 years. Patients with atypical carcinoids were 10 years older than patients with typical ones. Eleven patients were smokers, all the patients with atypical and 4 patients with typical carcinoid. The most common presenting mode was pneumonia. Fiberoptic bronchoscopy was diagnostic in 11 cases. The survival rate for patients with typical carcinoid was 100%, while it was 57% in patients with atypical carcinoids. Patients with limited disease had a survival of 100%, while in stage III/IV patients showed a lower survival rate (50%). In conclusion, carcinoid tumors of the lung are tumors showing a good prognosis. Five-year survival indicated a significant difference between typical and atypical carcinoids and between limited and extensive disease. A precise staging is recommended for a better treatment and follow-up.

International audience

After a thorough analysis of the industrial needs and of the limitations of current simulation tools, EDF and CEA (Commissariat a l’Energie Atomique) launched the NEPTUNE Project in 2001 (see Guelfi et al., 2007 ) with the support of AREVA-NP and IRSN. The NEPTUNE activities include software development, research in physical modeling and numerical methods, development of advanced instrumentation techniques and new experimental programs. Four different simulation scales were addressed including DNS (Direct Numerical Simulation), CFD in open medium (Computational Fluid Dynamics), component (subchannel-type analysis) and system (reactor modeling) scales. In 2006 CEA, EDF, AREVA-NP and IRSN defined the strategy for the system scale of NEPTUNE and the CATHARE-3 development was launched. The main objectives are: • advanced physical modeling of two-phases flows, mainly by using multi-field and turbulence models, • improved 3D modeling by the use of fine and non conforming structured meshes, • generalized coupling capabilities with other thermal-hydraulic scales and with other disciplines (core physics, structural mechanics, …), • extension of the applicability to new Gen IV reactors (Sodium Cooled Fast Breeder Reactors, Gas Cooled Reactors, Supercritical Light Water Reactors), • a true object-oriented code architecture. At the same time CATHARE-3 is in continuity with the CATHARE-2 code which is the current industrial version of CATHARE and internationally used for nuclear power plant safety analysis, in simulators and in coupled simulation tools. The road map of these two codes will allow a smooth transition from CATHARE-2 to CATHARE-3 for all users. This paper gives an overview of the choices made for the development of CATHARE-3 including new physical models, validation strategy and experimental programs, numerical improvements, enhanced coupling capability and software architecture evolution. The current status of the project as well as the overall schedule will be presented.

In unresectable non-small cell lung cancer (NSCLC) with a patent mainstem bronchus, some studies of obstructive tumors, showed (1) a poor role for irradiation in obtaining efficient debulking and (2) an interest in preliminary laser treatment in these patients. Cryotherapy is another method to obtain debulking. Moreover, several studies showed that cryotherapy would increase the radiosensitivity of a tumor. We performed a preliminary protocol combining successively initial cryotherapy followed by irradiation in inoperable NSCLC (either for local or functional contraindications). Thirty-eight patients were included and treated first by cryotherapy performed under general anesthesia and then with external irradiation in a curative intent. The efficiency of cryotherapy assessed on bronchoscopy was found to be volume-efficient (VE) in 26 of the 38 patients and non-volume-efficient (NVE) in the other 12 patients. After irradiation in the VE group, 17 of the 26 patients had no bronchial residual tumor (NRT). In contrast, all of the patients in the NVE group had a bronchial residual tumor (RT). Survival in the VE group (median, 397 days) was significantly higher than the survival of the NVE group (median, 144 days). Survival was found to be independent of the surgical contraindication (local or functional). The best survival was associated both with the efficiency of the initial debulking (VE) by cryotherapy and with the local control (NRT) induced by the irradiation (median, 560 days). Local control was obtained in 65 percent (17/26) of the cases in the VE group and was never observed in the NVE group. In our study the VE group's local control is better than the 35 percent usually reported after irradiation alone. These results argue for the efficient potentiation of irradiation by cryotherapy. (Chest 1992; 102:1436-40)

Vasospasm of RP is thought to occur in the lungs. To assess pulmonary vasospasm, we analyzed the early and late Dsb variations after a digital CPT. Sixteen normal volunteers and 20 patients (7 with primary, 13 with secondary RP) were included. A clinical RP was conducted on ten patients, nine with secondary and one with primary RP. The Dsb analysis showed: no significant variations in control subjects, a quick and short fall in primary RP significant after 15 min and a delayed fall in secondary RP significant after 45 min. A Dsb decrease was noticed even if no clinical RP occurred. The pallor phase of RP was associated with a concomitant decrease in the DCO and the hyperemic phase, with a Dsb increase. These results agree with those of previous studies with a few differences.

We report the case of a young woman presenting with dyspnoea of effort. Her records noted that correction of a double aortic arch had been performed in the neonatal period. At rest her flow/volume loop showed a moderate reduction of peak flow without an expiratory plateau. Exercise capacity was limited by sudden onset, during the last 2 stages of the test, of inspiratory dyspnea and tachypnea. During recovery there was no evidence of bronchospasm.With this picture we suspected upper airway obstruction and bronchoscopy revealed tracheal compression to 50% of normal. CT scan with 3 dimensional reconstruction showed the trachea compressed between 2 aortic branches. In order to confirm that the tracheal compression increased during exercise we induced sympathetic stimulation by a "handgrip" test that reproduced the inspiratory dyspnea and lead to a reduction in inspiratory flows.We have thus demonstrated that the increase in tracheal compression leading to limitation of airflow on exercise was due to an increase in aortic pressure and not to an increase in ventilatory flows.

International audience

The hepatopulmonary syndrome (HPS) associates a chronic hepatic affection, hypoxemia70 mm Hg and pulmonary vasodilatation.The mechanisms leading to pulmonary vasodilatation are complex and unclear. There appears to be an imbalance between the vasodilatating and vasoconstricting mediators. Nitrogen monoxide and endotheline-1 are well known. Hypoxia can be explained by the association of heterogenic ventilation-perfusion, shunts (rare), and a default in "diffusion-perfusion".In a hypoxic patient, platypnoea and orthodeoxia are characteristic of HPS. Stellar angioma associated with digital hippocratism and signs of portal hypertension are usually present.The air of blood gases, followed by 100% O2, standing and reclining, must be measured in all cirrhotic patients to detect hypoxemia. Contract sonography is the key diagnostic examination. Pulmonary perfusion scintigraphy establishes prognosis. Pulmonary angiography differentiates two groups of patients and, for type II patients, embolization therapy can be proposed. Preliminary data indicate that densitometry, conducted in rigorous conditions, can show pulmonary vasodilatation. Its interest must be confirmed by further studies on larger cohorts of patients.The only efficient treatment of HPS is hepatic transplant (HT). The placing of an intra-hepatic portal systemic shunt can be proposed while waiting for HT, or in certain patients not requiring HT. No medical treatment has demonstrated its efficacy, but better knowledge of the physio-pathologic mechanisms should improve this situation in the future.

A benign oropharyngial infection without appropriate treatment can be complicated by a jugular vein thrombosis and disseminated septic embolies with deleterious pulmonary effects. This septic clinical picture most commonly known as Lemierre syndrome is attributed to Fusobacterium necrophorum, a Gram negative anaerobic bacilli. We describe a case of a young patient who has presented this syndrome accompanied by typical pulmonary manifestations. Adequate antibiotic treatment for 3 weeks associated with anticoagulant treatment for about 3 months duration have allowed a complete recovery without sequel.

The increased sympathetic activation that occurs in obstructive sleep apnoea (OSA) may play an important role in associated morbidity. We investigated the effect of long-term (3 month) nasal continuous positive airway pressure (CPAP) on the autonomic nervous system assessed by heart rate variability (HRV). Fourteen patients (12 men), mean age 61.4 +/- 8.1 years, with OSA underwent continuous synchronized electrocardiographic and polysomnographic monitoring. The apnoea/hypopnoea index (AHI) decreased from 50.6 +/- 13.7 to 2.2 +/- 2.5 events h-1 after CPAP. HRV analysis showed significant decreases in low frequency (LF; from 7.12 +/- 1.06 to 6.22 +/- 1.18 ln ms2 Hz-1; P0.001), high frequency (HF; from 5.91 +/- 0.87 to 5.62 +/- 0.92 ln ms2 Hz-1; P0.05) and LF/HF (from 1.21 +/- 0.12 to 1.11 +/- 0.15 ln ms2 Hz-1; P0.001) when the patients were asleep. The decrease in LF/HF was prolonged into the daytime (from 1.33 +/- 0.22 to 1.24 +/- 0.21 ln ms2 Hz-1; P0.001). Treatment of OSA by CPAP significantly reduced the parameters of cardiac sympathetic tone, a favourable effect.

The aortic rupture in the pulmonary parenchyma or the bronchi rarely results in an haemoptysis. It means in most of the cases the rupture of an aortica aneurysm. We relate the observation of a aorto-bronchial fistula from a tuberculosa origin in an old woman case. Although the tuberculosa aortitis is becoming very exceptional, it still remains the cause of aorta rupture, with the formation of a false aneurysm which is rapidly fatal and so, it is important to search for it before any capricious haemoptysis.

The structure of a new generation of thermalhydraulic code: Trio- Unitaire is presented in this paper. This code has been designed to solve large 3D structured or unstructured CFD problems. The solutions adopted to achieve this goal (object-oriented design and parallelism) are described and the paper focuses on the technical solutions used. Some preliminary experimental results on a Cray T3E are presented.

This study investigated 22 patients with histologically proven primary bronchial carcinoids and in particular the relationship between assessment parameters and survival. In each patient, age, sex, smoking habits, mode of presentation, results of diagnostic investigations, methods of treatment and pathological examination of resected specimens were recorded. Follow-up was possible in all patients for at least 5 years. Patients with atypical carcinoids were 10 years older than patients with typical ones. Eleven patients were smokers, all the patients with atypical and 4 patients with typical carcinoid. The most common presenting mode was pneumonia. Fiberoptic bronchoscopy was diagnostic in 11 cases. The survival rate for patients with typical carcinoid was 100%, while it was 57% in patients with atypical carcinoids. Patients with limited disease had a survival of 100%, while in stage III/IV patients showed a lower survival rate (50%). In conclusion, carcinoid tumors of the lung are tumors showing a good prognosis. Five-year survival indicated a significant difference between typical and atypical carcinoids and between limited and extensive disease. A precise staging is recommended for a better treatment and follow-up.

Stent placement is the only available treatment in patients presenting either a localized external compression or a malacia of the tracheobronchial tree. To assess the functional benefit of prosthesis insertion in these indications, we compared functional respiratory values before, immediately after (48 h), and at sometime after (mean, 10.1 months) operation in 24 patients presenting with a bronchial lesion (B group, n = 5) or a lesion of the intrathoracic part (ITT group, n = 9) or of the extrathoracic part of the trachea (ETT group, n = 10). Before treatment, airflow was severely impaired in most patients without significant differences among the groups. After prosthesis insertion, airflow parameters increased [change in forced expiratory volume in 1 s (delta FEV1 = 440 mL; delta peak expiratory flow (PEF) = 0.92 L.s-1; delta maximum expiratory flow 25/75 (delta MEF25/75) = 0.47 L.s-1; and delta forced inspiratory volume in 1 s (delta FIV1 = 310 mL)] and airway resistances (Raws) decreased (delta Raw = -0.43 kPa.s-1.s-1) without any significant variation in either forced vital capacity (FVC) or total lung capacity. Airflow improvement was more apparent in ITT and ETT groups than in the B group. Moreover, inspiratory flow increase and decrease of FEV1/PEF ratio were only observed in the ETT group. This airflow improvement was maintained for a long time after and was associated with a good clinical tolerance. This study supports the clinical and functional benefits of prosthesis placement both in benign and malignant airway compressions for palliative treatment.

We performed polysomnography and measured hypoxic ventilatory (HVR), hypercapnic ventilatory responses (HCVR) in 42 patients (60 +/- 11 years) with obesity and a clinical suspicion of sleep apnea syndrome (SAS) in order to determine whether an altered chemosensitivity was associated with SAS. The apnea/hypopnea index was 38 +/- 20 events per hour of sleep in 28 patients (SAS+ group) and less than 10 in the 14 others (SAS- group). The 2 groups differed only by a lower waking PaO2 in SAS+ as compared to SAS- (71.0 +/- 9 vs 77.4 +/- 8 mmHg, p0.05). HVR and HCVR were not significantly different in the 2 groups (0.82 +/- 0.58 vs 0.86 +/- 0.37 l.min-1.%-1; 1.41 +/- 0.81 vs 1.40 +/- 0.67 l.min-1.mmHg-1, respectively). In SAS+ group, HVR or HCVR did not change 3 or 12 months after continuous positive airway pressure (CPAP) therapy while both polysomnography and PaO2 returned to normal. We conclude that in patients with mild obesity and SAS there is no difference in chemosensitivity due to the presence of sleep apnea and that CPAP therapy does not alter these measurements. These results suggest no direct effect of SAS on chemosensitivity in the population studied.

International audience; A proper understanding of the pulmonary toxicology of man-made mineral fibres (MMMF) requires information on their durability in the human lung but to date there is little information on this subject. Recently however, we have had the opportunity to document some interesting aspects of the short-term durability of ceramic fibres in human lung by analysing fibres recovered in broncho-alveolar lavage fluid obtained frorn seven men currently employed in the MMMF production industry. Fibres recovered from the lungs by lavage were characterized by analytical transmission electron microscopy. Both normal and highiy-transfonned ceramic fibres were detected. The transformed fibres exhibited a spectrum ofmorphological features and elemental compositions. Some retained a typical ceramic chemistry but were heavily coated with ironcontaining material. Others had a hollow tube morphology, made up offine iron-containing granules without any of the normal major ceramic elements. Such fibres were sometimes found lying under a bed ofsiliceous Seachate. It is hypothesized (hat the transformation process first involves a coating of the ceramic fibres with iron-containing granules, followed by a progressive dissolution of the structural elements. We conclude that some ceraraic fibres are not durable in the human lung.

A proper understanding of the pulmonary toxicology of man-made mineral fibres (MMMF) requires information on their durability in the human lung but to date there is little information on this subject. Recently however, we have had the opportunity to document some interesting aspects of the short-term durability of ceramic fibres in human lung by analysing fibres recovered in broncho-alveolar lavage fluid obtained frorn seven men currently employed in the MMMF production industry. Fibres recovered from the lungs by lavage were characterized by analytical transmission electron microscopy. Both normal and highiy-transfonned ceramic fibres were detected. The transformed fibres exhibited a spectrum ofmorphological features and elemental compositions. Some retained a typical ceramic chemistry but were heavily coated with ironcontaining material. Others had a hollow tube morphology, made up offine iron-containing granules without any of the normal major ceramic elements. Such fibres were sometimes found lying under a bed ofsiliceous Seachate. It is hypothesized (hat the transformation process first involves a coating of the ceramic fibres with iron-containing granules, followed by a progressive dissolution of the structural elements. We conclude that some ceraraic fibres are not durable in the human lung.