Evaluation of native microalgae from Tunisia using the pulse-amplitude-modulation measurement of chlorophyll fluorescence and a performance study in semi-continuous mode for biofuel production.

BACKGROUND: Microalgae are attracting much attention as a promising feedstock for renewable energy production, while simultaneously providing environmental benefits. So far, comparison studies for microalgae selection for this purpose were mainly based on data obtained from batch cultures, where the lipid content and the growth rate were the main selection parameters. The present study evaluates the performance of native microalgae strains in semi-continuous mode, considering the suitability of the algal-derived fatty acid composition and the saponifiable lipid productivity as selection criteria for microalgal fuel production. Evaluation of the photosynthetic performance and the robustness of the selected strain under outdoor conditions was conducted to assess its capability to grow and tolerate harsh environmental growth conditions. RESULTS: In this study, five native microalgae strains from Tunisia (one freshwater and four marine strains) were isolated and evaluated as potential raw material to produce biofuel. Firstly, molecular identification of the strains was performed. Then, experiments in semi-continuous mode at different dilution rates were carried out. The local microalgae strains were characterized in terms of biomass and lipid productivity, in addition to protein content, and fatty acid profile, content and productivity. The marine strain Chlorella sp. showed, at 0.20 1/day dilution rate, lipid and biomass productivities of 35.10 mg/L day and 0.2 g/L day, respectively. Moreover, data from chlorophyll fluorescence measurements demonstrated the robustness of this strain as it tolerated extreme outdoor conditions including high (38 °C) and low (10 °C) temperature, and high irradiance (1600 µmol/m2 s). CONCLUSIONS: Selection of native microalgae allows identifying potential strains suitable for use in the production of biofuels. The selected strain Chlorella sp. demonstrated adequate performance to be scaled up to outdoor conditions. Although experiments were performed at laboratory conditions, the methodology used in this paper allows a robust evaluation of microalgae strains for potential market applications.

Selection of native Tunisian microalgae for simultaneous wastewater treatment and biofuel production.

This paper focuses on the selection of native microalgae strains suitable for wastewater treatment and biofuel production. Four Chlorophyceae strains were isolated from North-eastern Tunisia. Their performances were compared in continuous mode at a 0.3 1/day dilution rate. The biomass productivity and nutrient removal capacity of each microalgae strain were studied. The most efficient strain was identified as Scenedesmus sp. and experiments at different dilution rates from 0.2 to 0.8 1/day were carried out. Maximal biomass productivity of 0.9 g/L day was obtained at 0.6 1/day. The removal of chemical oxygen demand (COD), ammonium and phosphorus was in the range of 92-94%, 61-99% and 93-99%, respectively. Carbohydrates were the major biomass fraction followed by lipids and then proteins. The saponifiable fatty acid content was in the 4.9-13.2% dry biomass range, with more than 50% of total fatty acids being composed of saturated and monosaturated fatty acids.

Malignant peripheral nerve sheath tumor of the superficial cervical plexus with parotid extension.

INTRODUCTION: Cervical locations of malignant peripheral nerve sheath tumor (MPNST) are rare, at less than 1% of malignant tumors of this region. CASE REPORT: A 53-year-old woman presented with a lateral cervical swelling involving the parotid region. Histology was in favor of MPNST. Adjuvant radiotherapy was indicated because of the infiltrating nature of the tumor. At 2 years' follow-up, there was no recurrence. DISCUSSION: Clinical diagnosis is difficult in cervical MPNST. Only histology with immunohistochemistry can establish the correct diagnosis. Treatment requires complete surgical resection and regular clinical follow-up.

[Maxillary sinusitis of odontogenic origin: surgical treatment]. / Sinusites maxillaires d'origine dentaire : traitement chirurgical.

PURPOSE: The frequency of maxillary sinusitis of dental origin (MSDO) is under estimated. The medical and surgical treatment has improved thanks to endoscopic guidance. We report our experience and strategy in the treatment of MSDO. PATIENTS AND METHODS: Twenty-two patients presenting with MSDO were treated between 1998 and 2008. The results were evaluated on clinical, functional, sinusal, and odontologic signs. RESULTS: MSDO accounted for 16% of surgically managed sinusitis. CT was performed in 95% of cases. The etiologies were apical leakage in seven patients, migration of a tooth or root during extraction, or presence of ectopic tooth in the sinus in nine patients, a cyst in three patients, and oroantral communication in three patients. Surgery was performed after antibiotic and NSAID treatment. The first surgical step was the treatment of the odontogenic source. The second step was sinus drainage by endoscopic treatment in 64%, Caldwell-Luc in 23%, and drainage by oroantral communication enlarged then closed in the same operative time in 13%. The follow up ranged from 3 months to 10 years. Early postoperative superinfection was observed in two patients. Two patients presented with recurrent sinusitis. The postoperative sequels were hyposmia in three patients, dental pulpotomy, and trigeminal neuralgia in five patients treated by Caldwell-Luc surgery. DISCUSSION: Nasal endoscopy has improved the surgical management of MSDO. It makes curettage and exclusion of sinus cavities obsolete. It is reliable and has a low rate of complications. The best treatment remains prevention.

Halanaerobacter jeridensis sp. nov., isolated from a hypersaline lake.

An obligatory anaerobic, moderately halophilic bacterium, designated strain CEJFG43(T), was isolated from a sample of sediment collected below the salt crust on the hypersaline El Jerid lake, in southern Tunisia. The cells of this novel strain were Gram-staining-negative, non-sporulating, motile, short rods. They grew in media with 6-30% (w/v) NaCl (optimum 15%), at 20-60 °C (optimum 45 °C) and at pH 5.5-9.5 (optimum pH 8.3). The micro-organism fermented glucose, fructose, ribose, raffinose, galactose, mannose, sucrose, maltose, xylose, mannitol, pyruvate and glycerol. The products of glucose fermentation were lactate, ethanol, acetate, H(2) and CO(2). The genomic G+C DNA content of strain CEJFG43(T) was 33.3 mol%. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain CEJFG43(T) belonged in the genus Halanaerobacter and was most closely related to Halanaerobacter lacunarum DSM 6640(T) (95.3% gene sequence similarity) and Halanaerobacter chitinivorans DSM 9569(T) (95.3%). The predominant cellular fatty acids were non-branched (C(16:0) and C(16:1)). Based on the phylogenetic and phenotypic evidence, strain CEJFG43(T) represents a novel species in the genus Halanaerobacter for which the name Halanaerobacter jeridensis sp. nov. is proposed. The type strain is CEJFG43(T) ( = DSM 23230(T) = JCM 16696(T)).

A Greedy Algorithm for Faster Feasibility Evaluation of All-Terminal-Reliable Networks.

Although calculating the all-terminal reliability (ATR) of a stochastic network is a computationally expensive task, deciding whether the ATR is greater than a preset value could be done with less effort. This study proposes a new method that generates the sequential lower and upper bounds of the ATR, based on greedy network factoring. The proposed method begins by finding the most reliable spanning tree and most unreliable cut set in the given network. Their operative and failing probabilities are used to update the lower and upper bounds of the ATR. Subnetworks are then produced, corresponding to each state of the spanning tree or cut set. This procedure is applied to the subnetworks in a recursive manner to update the ATR bounds further, until either the lower or upper bound reaches the preset ATR requirement. Due to the rapid convergence of the ATR bounds, the feasibility of a given network is likely to be decided at an early stage of the network factoring process. This study proposes several different implementations of the greedy algorithm and introduces the results of the computer experiments comparing them. Based on the experimental results, this study suggests a relationship between the performance of each implementation and the characteristics of the given network, such as layout and edge operating probabilities.

[Risk factors for recurrence of maxillary odontogenic keratocysts]. / Les facteurs de risque de récidive des kératokystes odontogéniques des maxillaires.

PURPOSE: The odontogenic keratocyst is a benign tumor with a high recurrence rate and aggressive behavior. We analyzed the risk factors for recurrence of odontogenic keratocysts and compared our results to published ones. PATIENTS AND METHODS: Thirty-two patients (36 odontogenic keratocysts) were treated in our department between 1996 and 2006. We retrospectively analyzed recurrence according to anatomoclinic, histopathological, and prognostic parameters. RESULTS: The patients' mean age was 41 years. The sex ratio was 1.28 with male predominance. The mandible was the most common site (30 cases). The most common radiological finding was a unilocular cyst in 75 % of cases. The primary treatment was conservative surgery for all patients. Twelve recurrences were observed in eight patients between 2 and 10 years of follow-up. All recurrences occurred in the mandible with 41 % in the angle and ramus. Multilocular cysts recurred in 55 % of cases, unilocular in 11 %. The recurrence rate of orthokeratocysts was 40 %. The presence of satellite cysts and extension to soft tissues were associated with a high rate of recurrence (60 %). Sixty-six percent of infected cysts recurred and among these, eight were enucleated in several fragments. DISCUSSION: The recurrence rate of odontogenic keratocysts is higher in case of mandibular posterior region localization and multilocular keratocysts. This might be explained by the difficult surgical accessibility. Some histological findings including the presence of satellite cysts and orthokeratocysts are associated with a higher recurrence rate. Cyst infection and treatment modalities influence the recurrence rate.

[Squamous cell carcinoma on a pleomorphic adenoma with amyloid stroma of the palate]. / Carcinome épidermoïde du palais sur adénome pléomorphe à stroma amyloïde.

INTRODUCTION: Squamous cell carcinoma ex-pleomorphic adenoma (CXAP) is a malignant and rare mixed tumor. We report a new case. OBSERVATION: A seventy-year-old woman consulted for a mass in the left hemi-face having evolved over the last 20years. The physical examination revealed a hard and large tumor invading all the palate. Computed tomography revealed a heterogeneous 8.5cm long maxillary mass. The diagnosis of CXAP was made on a biopsy. A histological study confirmed the diagnosis after surgical resection of the tumor, specifying its noninvasive character. DISCUSSION: CXAP is generally located in the parotid gland; it is very rarely located in the palate. The degenerated epithelial component generally corresponds to an adenocarcinoma or an undifferentiated carcinoma; squamous-cell carcinoma is more rarely reported. The prognosis is excellent for the micro and noninvasive types. Surgery remains the treatment of choice.

[Extrafollicular adenomatoid odontogenic tumour: report of two cases]. / Tumeur odontogène adénomatoïde extrafolliculaire: à propos de deux cas.

The purpose of this study was to analysis the clinicopathological features of adenomatoid odontogenic tumour extrafollicular and to discuss the diagnosis pitfull. We present two cases diagnosed and followed at the C.H.U. Habib Bourguiba, Sfax. It is about a 15 year-old boy and a 46 year-old woman who presented gingival swelling. The panoramic radiographs showed in both cases, a radiolucent area affecting teeth 23, 24 and 35 respectively. A computed tomography scan, realized at the second cas, demonstrated an expansile lesion with a sclerotic rim. An exploratory surgical approach was chosen and the final diagnosis was microscopically confirmed to be an extrafollicular variant of adenomatoid odontogenic tumour. The patients were healthy and have not shown any signs of recurrence at follow-up. The two cases described illustrate clinical and radiographic features of the extrafollicular variant of adenomatoid odontogenic tumour. Careful diagnostic procedure and adequate interpretation of radiographic findings may result in a correct diagnosis with otherwise may result in unnecessary endodontic treatment.

[Mandibular desmoplastic fibroma: diagnosis and therapeutics difficulties]. / Fibrome desmoïde mandibulaire : difficultés diagnostiques et thérapeutiques.

INTRODUCTION: The desmoplastic fibroma is a rare bone tumor, characterized by aggressive local infiltration, with frequent recurrence. The most common site is the mandible. Radioclinical signs are not specific and the histological diagnosis may be difficult. CASE: A 16 year-old male patient consulted for a painless and hard left mandibular swelling, without inferior alveolar nerve disorders. The tumor extended from tooth 31 to tooth 35, the mucosa was healthy. The panoramic view showed a multilocular osteolytic lesion with dental root resorption. CT scan showed expansion of bony cortex with rupture of the outer cortical. The biopsy indicated a desmoplastic fibroma or a fibrosarcoma. A second histological analysis combined with an immuno-histochemical study proved the diagnosis of desmoplastic fibroma. DISCUSSION: The desmoplastic fibroma has a polymorphous symptomatology. Radiological signs are unspecific. Anatomopathology combined with immuno-histochemistry can prove the diagnosis and guide the treatment.

[Melanotic schwannoma of the temporozygomatic region]. / Schwannome mélanocytique de la région temporozygomatique.

INTRODUCTION: Melanotic schwannoma is a rare benign tumor, which arises from nerve sheath cells. Melanotic differentiation is its most histologic characteristic. CASE REPORT: We report a case of melanotic schwannoma arising in the temporozygomatic region for a man of 38-year-old. Outcome was favourable after tumor resection. DISCUSSION: This benign neoplasm occurs pronominally in spinal nerve roots. Craniofacial locations are rare. Most melanotic schwannomas are slow growing tumors, but prognosis can be poor because of local recurrence or malign behavior, especially when multiple lesions are present and/or involve the Carney complex.

[Mandibular Langerhans cell histiocytosis]. / Histiocytose langerhansienne mandibulaire.

INTRODUCTION: Langerhan's cell histiocytosis is defined as an abnormal proliferation of Langerhans cells in various organs and tissues (bone, skin, lymph nodes...). Among facial locations, mandibular involvement is the most frequent and occurs in young people less than 20 years. The aim of this report is to review the characteristic features of this disease, the current means of diagnosis and treatment through two case reports. CASES: Two male patients aged 10 and 55 years respectively presented with single mandibular location of Langerhans cell histiocytosis. The diagnosis was confirmed by histological examination of the biopsy specimen. The first patient underwent surgical resection of the tumor. No recurrence was observed. In the second patient, the postoperative course was marked by the appearance of an inflammatory phenomenon in the adjacent skin and mucosa, successfully treated by intralesional corticosteroid therapy. DISCUSSION: Langerhan's cell histiocytosis is a rare disease. The mandibular location has variable clinical expressions which can vary from dental mobility to tumor development in the gingiva. The radiological appearance is also variable; histological proof is required for diagnosis. Treatment depends on the number and locations of the lesions. In case of a single location, the treatment options may vary from a "wait and see" attitude to a non aggressive surgery, with a possible local corticosteroid therapy or radiothe-rapy. For multiples locations, chemotherapy is indicated.

[Analysis of optic nerve head by confocal scanning laser ophthalmoscope in ocular hypertension]. / Analyse de la topographie de la tête du nerf optique par l'ophtalmoscope laser à balayage confocal dans les hypertonies oculaires.

PURPOSE: To analyze optic nerve head topography using confocal the scanning laser ophthalmoscope (CSLO) in ocular hypertension in comparison to normal eyes. PATIENTS AND METHODS: We examined 25 patients with ocular hypertension and 27 normal controls. All of them had a complete ophthalmic examination. Optic nerve head analysis was performed by using a CSLO-type Heidelberg retina tomograph (HRT). The following stereometric parameters were evaluated: disc area, area and volume of cup, cup/disc ratio, area and volume of neuroretinal rim, mean and maximal cup depth, cup shape measure, height variation contour, mean retinal nerve fiber layer thickness, and retinal nerve fiber layer (RNFL) cross-section area. RESULTS: In ocular hypertension eyes, rim volume, height variation contour and RNFL thickness showed a statistically significant reduction compared to normal eyes. CONCLUSION: HRT appears to be an important tool in detecting early damage of retinal nerve fiber layer in ocular hypertension.

Learning-based resource optimization in asynchronous transfer mode (ATM) networks.

This paper tackles the issue of bandwidth allocation in asynchronous transfer mode (ATM) networks using recently developed tools of computational intelligence. The efficient bandwidth allocation technique implies effective resources utilization of the network. The fluid flow model has been used effectively among other conventional techniques to estimate the bandwidth for a set of connections. However, such methods have been proven to be inefficient at times in coping with varying and conflicting bandwidth requirements of the different services in ATM networks. This inefficiency is due to the computational complexity of the model. To overcome this difficulty, many approximation-based solutions, such as the fluid flow approximation technique, were introduced. Although such solutions are simple, in terms of computational complexity, they nevertheless suffer from potential inaccuracies in estimating the required bandwidth. Soft computing-based bandwidth controllers, such as neural networks- and neurofuzzy-based controllers, have been shown to effectively solve an indeterminate nonlinear input-output (I-O) relations by learning from examples. Applying these techniques to the bandwidth allocation problem in ATM network yields a flexible control mechanism that offers a fundamental tradeoff for the accuracy-simplicity dilemma.

The hierarchical expert tuning of PID controllers using tools of soft computing.

We present soft computing-based results pertaining to the hierarchical tuning process of PID controllers located within the control loop of a class of nonlinear systems. The results are compared with PID controllers implemented either in a stand alone scheme or as a part of conventional gain scheduling structure. This work is motivated by the increasing need in the industry to design highly reliable and efficient controllers for dealing with regulation and tracking capabilities of complex processes characterized by nonlinearities and possibly time varying parameters. The soft computing-based controllers proposed are hybrid in nature in that they integrate within a well-defined hierarchical structure the benefits of hard algorithmic controllers with those having supervisory capabilities. The controllers proposed also have the distinct features of learning and auto-tuning without the need for tedious and computationally extensive online systems identification schemes.

Classification of underground pipe scanned images using feature extraction and neuro-fuzzy algorithm.

Pipeline surface defects such as holes and cracks cause major problems for utility managers, particularly when the pipeline is buried under the ground. Manual inspection for surface defects in the pipeline has a number of drawbacks, including subjectivity, varying standards, and high costs. Automatic inspection system using image processing and artificial intelligence techniques can overcome many of these disadvantages and offer utility managers an opportunity to significantly improve quality and reduce costs. A recognition and classification of pipe cracks using images analysis and neuro-fuzzy algorithm is proposed. In the preprocessing step the scanned images of pipe are analyzed and crack features are extracted. In the classification step the neuro-fuzzy algorithm is developed that employs a fuzzy membership function and error backpropagation algorithm. The idea behind the proposed approach is that the fuzzy membership function will absorb variation of feature values and the backpropagation network, with its learning ability, will show good classification efficiency.

[Rhinocerebral mucormycosis: apropos of 4 new Tunisian cases]. / Les mucormycoses rhinocérébrales: à propos de 4 nouveaux cas tunisiens.

Mucormycosis is a rare opportunistic infection but a fulminant disease. We report the 4 first cases of rhinocerebral mucormycosis diagnosed in Sfax region (Tunisia). They occurred in insulin dependent diabetes and developed varying clinical manifestations from facial cellulites to ocular and cerebral extension. The diagnosis of mucormycosis was not initially evoked, but confirmed tardively by anatomopathologic and mycologic examinations. The evolution was favourable in 2 cases by administration of amphotericine B associated with extensive surgical debridement and correction of the diabetes. Two patients had a fatal outcome. This infection has a severe prognosis and necessitates early diagnosis.

[Blepharitis due to Demodex: myth or reality?]. / Blépharite à Démodex: mythe ou réalité?

PURPOSE: Demodex folliculorum has been incriminated in the development of blepharitis although much controversy persists. Certain authors suggest that Demodex is a direct pathogen in chronic palpebral conditions while others consider the saprophyte to be innocuous to skin. METHODS: We conducted a prospective study of eyelashes in 100 persons, searching for Demodex folliculorum and chronic blepharitis. Microscopy in immersion oil after storage in a moist chamber was performed. RESULTS: The incidence of Demodex folliculorum was very high in patients with blepharitis compared with normal controls. Incidence increased with age. Harmless cuffs around the base of the eyelashes was found in 4% with Demodex irradior. CONCLUSION: Demodex should be considered as the cause of chronic blepharitis. Anti-Demodex treatment is indicated when the parasite is found.