A simple mass balance tool to predict carbon and nitrogen fluxes in anaerobic digestion systems.

The increase in anaerobic digestion systems has profoundly affected the waste management of territories, particularly for agricultural systems. Changes in cultural practices and imports of organic waste modify the carbon (C) and nitrogen (N) fluxes on territories where anaerobic digestion is implemented. Successful anaerobic digestion can increase the economic and ecological efficiency of the waste management system. Conversely, poor anaerobic digestion leads to low economic and environmental efficiency due to greenhouse gas emissions and nutrient loss. Modeling the impact of anaerobic digestion on the systems integrating anaerobic digestion can improve the efficiency of these practices. The aim of this study was to develop, analyze, and evaluate a simple mass balance tool able to predict carbon and nitrogen fluxes in anaerobic digestion systems. The tool is composed of an exhaustive substrate database used by three models: (i) an anaerobic digestion model that predicts C and N contents in biogas and digestate; (ii) a phase separation model that predicts C and N content in liquid and solid phase digestates; and (iii) a storage model that predicts C and N content in raw, liquid phase, and solid phase digestates, as well as C and N emissions during storage. Sensitivity analyses were performed on the tool to determine critical inputs. Sensitivity analysis showed that outputs were highly sensitive to their respective inputs and to total inputs of solids. Performance evaluation showed that the tool can provide good quality predictions with R2 correlations between observation and prediction varying from 0.72 to 0.99 with the best predictions obtained for raw digestate.

Zirconium arene triple-decker sandwich complexes: synthesis, electronic structure and bonding.

Reduction of a permethylpentalene zirconium(iv) chloride complex [η8-Pn*Zr(µ-Cl)3/2]2(µ-Cl)2Li·THFx with KC8 in benzene results in activation of the aromatic solvent to yield an "inverted sandwich" complex, [η8-Pn*Zr]2(µ-η6:η6-C6H6) (1). The reactions in toluene, cumene, o-xylene and m-xylene also yield analogous solvent activated triple-decker sandwich complexes, which have been structurally characterised by single-crystal X-ray diffraction. Edge energies in the Zr K-edge XANES spectra are not distinguishable between 1 and formally Zr(ii) and Zr(iv) reference compounds, suggesting a broad edge structure. DFT calculations best describe the bonding in 1 as highly covalent with frontier molecular orbitals showing almost equal contributions from benzene and the Zr-permethylpentalene fragments.

Susceptibility of Cabbage Maggot Larvae (Diptera: Anthomyiidae) to Hypocreales Entomopathogenic Fungi.

The pathogenicity of six Metarhizium spp., four Beauveria bassiana (Balsamo) Vuillemin, and four Tolypocladium cylindrosporum Gams (Ascomycota: Hypocreales) fungal pathogens exposed to third-instar Delia radicum L. was evaluated in laboratory bioassays. The presence of intra- and intergeneric variations concerning the pathogenicity of the isolates was investigated. Results show that all Metarhizium spp. and T. cylindrosporum isolates caused a noteworthy mortality to the third instar and consequently reduced adult eclosion. The well-known standard, F52 strain (identified as Metarhizium brunneum), resulted in up to 79% reduction in D. radicum eclosion. The other Metarhizium isolates including UAMH 9197 (Metarhizium anisopliae) and UAMH 2801 (M. brunneum), as well as T. cylindrosporum DAOM 167325 and DAOM 183952, produced a mean eclosion reduction of >50%. While the pathogenicity of Metarhizium spp. and T. cylindrosporum is similar, the B. bassiana isolates are undoubtedly less pathogenic. Based on the results obtained with the selected isolates, no intrageneric differences relative to the pathogenicity of the isolates appeared to be present. Globally, this study deepened the knowledge about D. radicum susceptibility toward Hypocreales entomopathogenic fungi, chiefly T. cylindrosporum. The implications of this study regarding the development of a biological control agent are discussed.

A waste characterisation procedure for ADM1 implementation based on degradation kinetics.

In this study, a procedure accounting for degradation kinetics was developed to split the total COD of a substrate into each input state variable required for Anaerobic Digestion Model n°1. The procedure is based on the combination of batch experimental degradation tests ("anaerobic respirometry") and numerical interpretation of the results obtained (optimisation of the ADM1 input state variable set). The effects of the main operating parameters, such as the substrate to inoculum ratio in batch experiments and the origin of the inoculum, were investigated. Combined with biochemical fractionation of the total COD of substrates, this method enabled determination of an ADM1-consistent input state variable set for each substrate with affordable identifiability. The substrate to inoculum ratio in the batch experiments and the origin of the inoculum influenced input state variables. However, based on results modelled for a CSTR fed with the substrate concerned, these effects were not significant. Indeed, if the optimal ranges of these operational parameters are respected, uncertainty in COD fractionation is mainly limited to temporal variability of the properties of the substrates. As the method is based on kinetics and is easy to implement for a wide range of substrates, it is a very promising way to numerically predict the effect of design parameters on the efficiency of an anaerobic CSTR. This method thus promotes the use of modelling for the design and optimisation of anaerobic processes.

Anaerobic co-digestion of waste activated sludge and greasy sludge from flotation process: batch versus CSTR experiments to investigate optimal design.

In this study, the maximum ratio of greasy sludge to incorporate with waste activated sludge was investigated in batch and CSTR experiments. In batch experiments, inhibition occurred with a greasy sludge ratio of more than 20-30% of the feed COD. In CSTR experiments, the optimal greasy sludge ratio was 60% of the feed COD and inhibition occurred above a ratio of 80%. Hence, batch experiments can predict the CSTR yield when the degradation phenomenon are additive but cannot be used to determine the maximum ratio to be used in a CSTR configuration. Additionally, when the ratio of greasy sludge increased from 0% to 60% of the feed COD, CSTR methane production increased by more than 60%. When the greasy sludge ratio increased from 60% to 90% of the feed COD, the reactor yield decreased by 75%.

[Concurrent administration of adjuvant chemotherapy and radiotherapy after breast-conservative surgery enhances late toxicities]. / La chimiothérapie concomitante de la radiothérapie augmente la toxicité tardive après chirurgie conservatrice du cancer du sein.

PURPOSE: In 1996, a multicenter randomized study comparing after breast-conservative surgery, sequential vs concurrent adjuvant chemotherapy (CT) with radiation therapy (RT) was initiated (ARCOSEIN study). Seven hundred sixteen patients were included in this trial. After a median follow-up of 6.7 (4.3-9) years, we decided to prospectively evaluate the late effects of these two strategies. PATIENTS AND METHODS: A total of 297 patients were asked to follow-up from the five larger including institutions. Seventy-two percent (214 patients) were eligible for late toxicity. After breast-conserving surgery with axillary dissection, patients were treated either with sequential treatment with CT first followed by RT (arm A) or CT administered concurrently with RT (arm B). In all patients, CT regimen combined mitoxantrone (12 mg/m(2)), 5-FU (500 mg/m(2)), and cyclophosphamide (500 mg/m(2)), 6 cycles (day 1-day 21). In arm B, patients received concurrently the first 3 cycles of CT with RT. In arm A, RT started 3 to 5 weeks after the 6th cycle of CT. Conventional RT was delivered to the whole breast using a 2 Gy-fraction protocol to a total dose of 50 Gy (+/-boost to the primary tumour bed). The assessment of toxicity was blinded to treatment and was graded by the radiation oncologist according to the LENT-SOMA scale. Skin pigmentation was also evaluated using a personal 5-points scoring system (excellent, good, moderate, poor, very poor). RESULTS: Among the 214 evaluated patients, 107 were treated in each arm. The two populations were homogeneous for patients', tumors' and treatment characteristics. Subcutaneous fibrosis (SF), telengectasia (T), skin pigmentation (SP), and breast atrophy (BA) were significantly increased in arm B. Twenty patients experienced grade superior or equal to 2 (SF) in arm B vs five in arm A (P=0.003). Twenty-five and seven patients showed grade superior or equal to 2 (T) in arm B and A, respectively (P=0.001). Forty-four and twenty patients showed grade superior or equal to 2 (BA) in arm B and A, respectively (P=0.0006). Thirty patients experienced grade superior or equal to 3 (SP) in arm B vs fifteen in arm A (P=0.02). No statistical difference was observed between the two arms concerning grade superior or equal to 2 pain, breast oedema, and lymphoedema. No deaths were caused by late toxicity. CONCLUSION: Following breast conserving surgery, the concurrent use of CT with RT is significantly associated with an increase incidence of grade 2 or greater late side effects.

Radiation and chemoradiation therapy for esophageal adenocarcinoma.

The aims of preoperative chemoradiation therapy (preop-CRT) for esophageal adenocarcinoma are to reduce incomplete local resection (R1,R2), local and systemic recurrences that are reported in up to 30% of patients who undergo surgery alone. Phase II studies of preop-CRT, with radiation doses in the 40-50 Gy range, and concurrent chemotherapy with 5-fluorouracil (5-FU)-cisplatin +/- paclitaxel, or cisplatin-paclitaxel, have reported subsequent RO resection rates of 80%-100%, with tumor sterilization achieved in 8%-49% of cases, and consequently improved local control. New chemotherapy regimens omitting 5-FU have reduced the incidence of severe esophagitis, unplanned hospitalization, with comparable efficacy. Among three randomised trials that compared preop-CRT to surgery alone, one shown a debatable survival advantage. Reducing local recurrence rates lead to a switch to more distant failures, and increasing the radiation dose beyond 45 Gy appears to be of little value. However, it should be remembered that preop-CRT has associated toxicity, and may increase postoperative mortality. Novel strategies, which include induction with chemotherapy followed by preop-CRT, and for radiation therapy, three dimensional conformation techniques, image fusioning, and improved definition of treatment volumes, are still considered experimental and should be tested in specialized centers.

Arteriovenous revascularization for lower limb salvage in unreconstructible arterial occlusive disease (long-term outcome).

Between February 1983 and June 1994 we attempted surgically to salvage twenty-six legs in twenty-five patients with insufficient distal run-off and severely ischemic feet; all of them had resting pain, and 23 had tissue necrosis. A saphenous venous graft was interposed between an artery of the lower extremity (femoral or popliteal) and the veins of the foot with obligatory end-to-side distal anastomosis. The patency of the venous circulation of the ischemic foot was ascertained by retrograde phlebography. Patients were followed from 3 months to 11 years (an average of 3 years and 5 months). In 19 legs (73%), surgery succeeded in preventing extensive gangrene of the foot, and allowed postponing or avoiding major amputation. The purpose of this paper is to analyze this experience, and stimulate further interest and study of the reversed microcirculation in critical ischemia.

[Comparative study of two methods of arterialization of foot veins in ischemic crisis]. / Etude comparative de deux modalités d'artérialisation des veines du pied en ischémie critique.

Between February 1974 and December 1991, a total of 28 arterializations of the venous network of foot were performed in patients with stage IIIB or IV arteriopathies presenting disseminated femoropopliteal and more distal lesions excluding revascularization by conventional arterial shunt operations. Two groups of patients could be distinguished. The first group, of 8 patients, underwent arterialization by shunt operation with end to end fistula at the distal part of leg and return blood emptying at the dorsal surface of foot (3 cases). The procedure was successful in 50% of cases after a mean follow up of 76 months. The intervention in the second group, of 20 patients, was by end to side fistula of foot after preoperative countercurrent phlebography and the use of a material better adapted for the destruction of the valves. Results were evaluated as successful in 70% of cases at 31 month follow up. After spontaneous closure of the fistula, the collateral circulation provoked by it was sufficient to conserve the acquired benefit. No deaths or cases of cardiac overload were reported as a result of the intervention. Comparative analysis of results showed that the use of the second procedure allowed amputation to be avoided in more than 2/3rds of cases, provided relief from pain, provoked healing of necrosed areas and permitted renewal of walking. The results of this study have demonstrated that venous arterialization of the foot by this method represents an interesting alternative in the saving of a limb destined for amputation.

[15-year evolution of loco-regional anesthesia for cataracts at a general hospital center]. / Réflexions sur l'évolution en 15 ans de l'anesthésie loco-régionale pour cataracte dans un Centre Hospitalier Général.

The fifteen year long practice of loco-regional anaesthesia for cataract surgery has led, because its growing complexity (operating microscope, extra-capsular procedure, IOL) to improving neuroleptanalgesia. The actual step using a weak dose of Propofol is described. The akinesy of patient and eye permits that kind of surgery, well accepted without the risks of deep general anaesthesia with intubation.

[Keratomileusis without freezing--results with a 6-month follow-up]. / Kératomyleusis non gel--résultats avec un recul de 6 mois.

The authors describe the planar lamellar refractive keratoplasty without freezing and the results for six months.

[Endotracheal tube for laryngeal CO2 laser microsurgery. 208 cases]. / Sonde d'intubation pour la microchirurgie laryngée par laser CO2. 208 observations.

To suppress the risk inherent in laryngeal microsurgery performed with a CO2 laser beam, the authors suggest to use a reinforced silicone endotracheal tube, the cuff of which is protected by a silicone plus aluminium powder shield. The resistance of silicone to fire is augmented during laser shots by a nitrogen flow on the upper side of the shield at the rates of 2 l/min in patients breathing air and 30 l/min in patients give oxygen.

[Multiple decubitus ophthalmological operating table]. / Table operatoire d'ophtalmologie à decubitus multiples.

A new ophthalmological operating table is presented which is adapted to the most recent developments in microsurgery and for the treatment of the most difficult cases of vitreoretinal pathology. The head of the table is mobile in the sagittal plane, movements being effected under remote-control by the surgeon at a rate of 2 mm/sec. The same movement can be applied to a horseshoe shaped armrest, which is solidly attached around the headpiece and is adjustable for height. A respiratory shield can be attached during local anesthesia, and the table can be positioned in proclivity or declivity. During vitreoretinal surgery, the table enables rotation of the patient in ventral decubitus along a longitudinal axis, rotation being possible manually or electrically. Proclivity and declivity positions can be obtained by rotation on a transversal axis. These functions assist exchanges between ocular fluids and substances used for internal packing, as well as passage into the anterior chamber of foreign bodies in the vitreal cavity.