Search Results - (Author, Cooperation:M. Hamdi)

2018-05-03

American Physical Society (APS)

1098-0121

1095-3795

Physics

Magnetism

2012-03-01

Nature Publishing Group (NPG)

0028-0836

1476-4687

Biology

Chemistry and Pharmacology

Medicine

Natural Sciences in General

Physics

Aging/genetics ; Chromosomes, Human/*genetics ; Cluster Analysis ; DNA Helicases/genetics ; DNA Mutational Analysis ; Gene Expression Regulation, Neoplastic ; Genome, Human/genetics ; Growth Cones/metabolism/pathology ; Guanine Nucleotide Exchange Factors/genetics ; Humans ; Mutation ; Neoplasm Staging ; Neurites/*metabolism ; Neuroblastoma/diagnosis/*genetics/metabolism/*pathology ; Nuclear Proteins/genetics ; Prognosis ; rac GTP-Binding Proteins/metabolism ; rho GTP-Binding Proteins/metabolism

0020-1693

Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

Chemistry and Pharmacology

Electronic Resource

0368-1874

Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

Chemistry and Pharmacology

Electronic Resource

0022-0728

Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

Chemistry and Pharmacology

Electronic Resource

0022-0728

Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

Chemistry and Pharmacology

Electronic Resource

1572-8188

optical networks ; Wavelength-Division-Multiplexing (WDM) ; real-time scheduling ; multiple-access protocols

Springer Online Journal Archives 1860-2000

Electrical Engineering, Measurement and Control Technology

Abstract One of the important issues in the design of future generation high-speed networks is the provision of real-time services to different types of traffic with various time constraints. In this paper we study the problem of providing real-time service to hard and soft real-time messages in Wavelength-Division-Multiplexing (WDM) optical networks. We propose a set of scheduling algorithms which prioritize and manage message transmissions in single-hop WDM passive star networks based on specific message time constraints. In particular, we develop time-based priority schemes for scheduling message transmissions in order to increase the real-time performance of a WDM network topology. We formulated an analytical model and conducted extensive discrete-event simulations to evaluate the performance of the proposed algorithms. We compared their performances with that of the state-of-the-art WDM scheduling algorithms which typically do not consider the time constraint of the transmitted messages. This study suggests that when scheduling real-time messages in WDM networks, one has to consider not only the problem of resources allocation in the network but also the problem of sequencing messages based on their time constraints.

Electronic Resource

1432-0797

Springer Online Journal Archives 1860-2000

Process Engineering, Biotechnology, Nutrition Technology

Abstract A convenient physical model for biomass involves consideration of individual cells as “active” centers dispersed through a continuous region in which transport takes place by molecular diffusion. This paper investigates for steady state conditions the variation of apparent kinetic constant (K m ′ ) of bacteria in relation to biofloc diameter with solid and/or liquid-phase diffusion. When the biochemical reactions are limited only by liquid-phase diffusion, theK m ′ increases whenD increases. With solid-phase diffusion limitation only, theK m ′ increases linearly with the diameterD of the floc. When both solid and liquid-phase diffusion limitations are considered, the apparentK m is affected by liquid-phase diffusion limitation with very smallD and by solid-phase diffusion limitation with higherD. The critical diameterD c can be assumed to be theD at which solid-phase diffusion limitation becomes more significant than liquid-phase diffusion limitation.

Electronic Resource

1432-0797

Springer Online Journal Archives 1860-2000

Process Engineering, Biotechnology, Nutrition Technology

Abstract The biological process for OMW treatment is based on an aerobic detoxification step followed by methanization step and aerobic post-treatment. The first aerobic detoxification step of OMW supplemented with sulfate and ammonium was carried out by the growth of Aspergillus niger in a bubble column. This step decreased OMW toxicity and increased its biodegradability because of phenolic compounds degradation. Growth of A. niger resulted in 58% COD removal, with production of biomass containing 30% proteins (w/w). Filtration of OMW was enhanced by this fermentation because the suspended solids were trapped in the mycelium. The filtrate liquid was then methanized using an anaerobic filter packed with flocoor. This reactor showed a short start up and a good stability. COD removal was around 60% and the methane yield (1 CH4/g COD removed) was close to the theoretical yield. The anaerobic filter effluent was treated in an activated sludge fluidized reactor containing olive husk as a packing material. Husks were maintained in fluidization state by the aeration. This step induces COD removal at 45% and sludge (up to 2 g/dm3). The entire process allowed a global COD reduction up to 90%; however, the black colour due to polyphenolic compounds with high molecular weight persisted.

Electronic Resource

1432-0797

Springer Online Journal Archives 1860-2000

Process Engineering, Biotechnology, Nutrition Technology

Abstract There has been an increasing number of biotechnical processes for use or treatment of olive mill wastewaters (OMW) over the last twenty years, both at laboratory size and on pilot scale. This paper reviews the methods described in the literature emphasizing the most important features and constraints of each of these processes.

Electronic Resource

0143-8166

Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

Electrical Engineering, Measurement and Control Technology

Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics

Physics

Technology

Electronic Resource

1433-7339

Key words Low-energy laser ; Mucositis ; Radiotherapy ; Head and neck cancer

Springer Online Journal Archives 1860-2000

Medicine

Abstract  Use of the low-energy helium-neon laser (LEL) appears to be a simple atraumatic technique for the prevention and treatment of mucositis of various origins. Preliminary findings, and significant results obtained for chemotherapy-induced mucositis in a previous phase III study, prompted a randomized multicenter double-blind trial to evaluate LEL in the prevention of acute radiation-induced stomatitis. Irradiation by LEL corresponds to local application of a high-photon-density monochromatic light source. Activation of epithelial healing for LEL-treated surfaces, the most commonly recognized effect, has been confirmed by numerous in vitro studies. The mechanism of action at a molecular and enzymatic level is presently being studied. From September 1994 to March 1998, 30 patients were randomized. Technical specification: 60 mW (25 mW at Reims, 1 patient), He-Ne, wavelength 632.8 nm. The trial was open to patients with carcinoma of the oropharynx, hypopharynx and oral cavity, treated by radiotherapy alone (65 Gy at a rate of 2 Gy/fraction, 5 fractions per week) without prior surgery or concomitant chemotherapy. The malignant tumor had to be located outside the tested laser application areas (9 points): posterior third of the internal surfaces of the cheeks, soft palate and anterior tonsillar pillars. Patients were randomized to LEL or placebo light treatment, starting on the first day of radiotherapy and before each session. The treatment time (t) for each application point was given by the equation : t (s)=energy (J/cm2)×surface (cm2)/Power (W). Objective assessment of the degree of mucositis was recorded weekly by a physician blinded to the type of treatment, using the WHO scale for grading of mucositis and a segmented visual analogue scale for pain evaluation. Protocol feasibility and compliance were excellent. Grade 3 mucositis occured with a frequency of 35.2% without LEL and of 7.6% with LEL (P〈0.01). The frequency of "severe pain" (grade 3) was 23.8% without LEL, falling to 1.9% with LEL (P〈0.05). Pain relief was significantly reduced throughout the treatment period (weeks 2–7). LEL therapy is capable of reducing the severity and duration of oral mucositis associated with radiation therapy. In addition, there is a tremendous potential for using LEL in combined treatment protocols utilizing concomitant chemotherapy and radiotherapy.

Electronic Resource

1432-0614

Springer Online Journal Archives 1860-2000

Biology

Process Engineering, Biotechnology, Nutrition Technology

Summary A microbial consortium obtained by enrichment culture on syringate of termite gut material was used to improve the anaerobic degradation of olive-mill waste-water (OMW). Addition of the consortium (1/4 v/v) to the control inoculum originating from waste-water sludge, increased methane production by 50% over the control during anaerobic digestion of OMW prefermented by Aspergillus niger. This increase was related to enhanced acetate production in the presence of the consortium. When OMW was not prefermented by A. niger, no improvement in methane production was observed, indicating that the aerobic degradation of inhibitory substances is needed for the consortium to express its potential.

Electronic Resource

0178-515X

Springer Online Journal Archives 1860-2000

Process Engineering, Biotechnology, Nutrition Technology

Abstract  A convenient physical model for biomass involves consideration of individual cells as “active” centers dispersed through a continuous region in which transport takes place by molecular diffusion. This paper investigates for steady state conditions the variation of apparent kinetic constant (K ′ m ) of bacteria in relation to biofloc diameter with solid and/or liquid-phase diffusion. When the biochemical reactions are limited only by liquid-phase diffusion, the K ′ m increases when D increases. With solid-phase diffusion limitation only, the K ′ m increases linearly with the diameter D of the floc. When both solid and liquid-phase diffusion limitations are considered, the apparent K m is affected by liquid-phase diffusion limitation with very small D and by solid-phase diffusion limitation with higher D. The critical diameter D C can be assumed to be the D at which solid-phase diffusion limitation becomes more significant than liquid-phase diffusion limitation.

Electronic Resource

0178-515X

Springer Online Journal Archives 1860-2000

Process Engineering, Biotechnology, Nutrition Technology

Summary Three Lactococcus strains (Lactococcus ssp. lactis var. diacetylactis, Lactococcus ssp. lactis cremoris and Lactococcus ssp. lactis var. lactis) isolated from the Tunisian lben were grown at constant pH on CSL medium in stirred fermentors for lactic starters production. The agitation required to homogenate alkali used to pH control should be low because it affects the Lactococcus growth. Scale up from 20-liter fermentor to 400-liter fermentor was carried out at constant impeller tip speed below 150 cm s−1. The CSL supplementation and fed-batch with glucose increased the yield in the upper 1010 cfu/ml. The consumed glucose during fermentation was converted into lactic acid and cell. Before fed-batch, the maximum specific growth rate of Lactococcus ssp. lactis var. diacetylactis was around 1 h−1 and the number of cells increased 20 to 40 times according to inoculum size. After fed-batch, the glucose consumption rate remains constant but specific growth rate decreased and number of cell trebled only.

Electronic Resource

0178-515X

Springer Online Journal Archives 1860-2000

Process Engineering, Biotechnology, Nutrition Technology

Abstract The biomass of prickly pear cladodes and fruits are a potential raw material for fermentations and are of particular consideration for arid and semi-arid regions, where its cultivation would also make use of an important land areas. This paper reviews the attempts of uses of prickly pear cladodes and fruits in food and biotechnological processes.

Electronic Resource

0178-515X

Springer Online Journal Archives 1860-2000

Process Engineering, Biotechnology, Nutrition Technology

Abstract Microbiol flora acclimated in continuous pilot scale bubble column fed with OMW was analysed. The most efficient isolated fungus was identified to white-rot fungus Geotrichum candidum. Decolorization of OMW by Geotrichum candidum was investigated by using Hadamard's matrix for screening the important parameters and optimize them in order to control the biological decolorization. Agitation favours the conversion of COD removed into Geotrichum candidum biomass especially with high arthoconodia and few mycelium. Dilution of OMW and aeration enhanced the mycelium growth and rammification which that allowed polyphenols hydrolysis and then a decolorization. The initial pH of OMW is suitable for its decolorization by Geotrichum candidum growth. Ammonium sulfate concentrations tested with different OMW dilutions showed that the COD:N:S ratio of 100:5:2 is suitable for higher black colour removal. With optimized conditions Geotrichum candidum growth on OMW in laboratory scale bubble column, the OD removal reached 70% and all fractions of polyphenolic compounds of OMW were oxidized.

Electronic Resource

1435-0130

Key words Cutaneous melanoma ; Head and neck ; Surgery ; Timing of surgery

Springer Online Journal Archives 1860-2000

Medicine

Abstract  The chart of 56 patients, consecutively operated on in our institution for malignant melanoma of the skin in the head and neck area from 1977 to 1993, were retrospectively reviewed. The follow-up was 2 to 18 years (average 7.5 years). We considered three kinds of treatment, looking at the adequacy and timing of surgery: (1) Planned definitive surgery (PDS), when surgery with adequate margins and lymph node dissection was done within two months after the initial diagnosis; (2) non-planned definitive surgery (non-PDS), when at least one of the above parameters could not be achieved; (3) and salvage surgery (Ss), for patients who presented with local recurrence or involved lymph nodes. Twenty-four patients were in the first group, ten in the second, and 22 in the third. Elective neck dissection was performed in 16 patients with a superficial spreading melanoma (SSM) or nodular melanoma (NM) lesion thicker than 1 mm, and a therapeutic radical neck dissection in 17 patients with a suspicious lymph node occurring at any stage of the disease. According to the type of surgical management, the five year survival was 90%, 60%, and 25% for PDS, non-PDS, and Ss groups, respectively (p〈0.01). Patients who were initially treated with elective lymph node dissection had better prognosis than those who had therapeutic lymph node dissection (88% versus 19% at 8 years, p〈0.001). These results further support the benefit of planned surgical treatment, i.e. within two months, for malignant melanoma of the head and neck.

Electronic Resource

0020-7608

Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics

Wiley InterScience Backfile Collection 1832-2000

Chemistry and Pharmacology

The mechanism of protonation of aminopyrones and the nature of the protonated forms are of some interest because of the biological importance of these compounds. The use of CNDO/2 molecular electrostatic potentials contour maps shows that the most reactive centre is the extracyclic oxygen. MNDO protonation energies confirm the protonation of this atom and elucidate the basicity of the nitrogen atom. The effect of a N substitution on the basicity of the N13 atom has been studied. The calculations are in agreement with preliminary experimental results.

2 Tab.

Electronic Resource

0029-5981

Engineering ; Engineering General

Wiley InterScience Backfile Collection 1832-2000

Mathematics

Technology

In order to study problems on fluid-structure interaction, we have used a mixed formulation which couples the classical functional of the structure with a new variational formulation by integral equations for the fluid. This formulation has the advantage over the finite element methods of avoiding the discretization of the fluid domain. Furthermore, unlike collocation methods, the explicit calculation of the Hadamard finite part of the singular integrals is avoided. This leads after discretization by boundary finite elements to a small and symmetrical algebraic system.Typical examples are presented that demonstrate the efficiency of this variational formulation by studying the sound transmission through a baffled plane structure and through a flexible panel backed by a rigid cavity. These include the calculation of the transmission loss factor and the determination of which modes dominate the noise transmission. Good agreement is obtained between numerical results and analytical results found in the literature.

13 Ill.

Electronic Resource