Tarissement et vidange des réservoirs de la Liane (Nord de la France)

Les courbes de tarissement de la Liane présentent la succession de trois tronçons correspondant à la vidange de trois réservoirs. Au fur et à mesure que la saison de vidange se prolonge, l'élimination de l'une des composantes souterraines de l'écoulement entraîne un changement de pente de la courbe annuelle de tarissement avec maintient de son allure générale ou bien provoque une chute des débits. Le régime de tarissement de chaque réservoir est fonction de sa capacité de stockage et des conditions d'alimentation. L'écoulement de la liane particulièrement lié à la complexité de ses réservoirs n'obéit pas aux régimes pluviométriques, et une faible corrélation existe entre le régime de tarissement et la pluie efficace pendant la saison de recharge. (Résumé d'auteur

Cold weather admixture systems for cement-based materials applied to masonry mortar binder

Masonry construction in cold weather is a challenge due to the slow or non-existent hydration reaction of the cementitious material at low and subfreezing temperatures. The construction industry’s need for an alternative to providing thermal protection has motivated the exploration of using antifreeze admixtures. The main objectives of this project were to develop and evaluate an effective antifreeze admixture for masonry mortars from available products, and to identify the active components responsible for promoting the strength gain and the mechanisms by which they act. In the first stage of the experimental program, an incomplete response surface design approach was used to develop an antifreeze admixture. The approach consisted of combining a total of six off-the-shelf concrete admixtures, up to five at a time at three dosage levels each. The target optimization function of the system was the minimization of the freezing point of the mortar, which was measured using an embedded thermocouple in the center of the mortar cylinders. Several combinations of admixtures were effective at lowering the freezing point of the mortar mix; however, the compressive strength was found not to be systematically correlated to the freezing temperature. The compressive strengths of mortar samples prepared with the best candidates, when cured at 10°C and 15°C, reached acceptable levels. However, a pre-curing (heat protection) period of between 6 and 12 hours was necessary for the mortar to reach these strength levels. The best performing candidate from the previous stage was selected to undergo further investigation to identify the active compound and to study its effect on the hydration process. Elemental and mineral characterization of the admixture, using mainly X-ray fluorescence (XRF) and X-ray diffraction (XRD), revealed a high concentration of sodium nitrite with some mullite, in addition to an unidentified amorphous phase. The characterization of the hydration products did not reveal any uncommon phases, suggesting the presence of a certain amount of unfrozen water in the pore structure that allowed the hydration reaction to proceed and the C S H phase to develop. The suspected active ingredient (sodium nitrite) was tested as a stand-alone admixture to confirm its action as an antifreeze agent, and produced masonry mortar with an acceptable 28-day compressive strength when cured at 10°C. No pre-curing period was required in this phase of testing. The dosage of sodium nitrite was also optimized and found to be approximately 5% by cement weight to maximize the strength gain. Given that no hard evidence of any unusual ongoing chemical reactions was found using the characterization techniques, the physical action of the antifreeze was investigated. The working hypothesis was that a certain amount of liquid water was present at subfreezing temperatures, which allowed the hydration reaction to proceed. As an indirect way of confirming the hypothesis, the non-destructive time domain reflectometry (TDR) technique was used to measure the bulk dielectric constant of the plain and treated cement pastes during the curing process up to an age of three weeks. A mixing model was formulated to quantitatively track the individual constituents of the cement paste, with a particular interest in the available liquid water at temperatures below the normal freezing temperature. The results showed clear evidence of the existence of liquid water in the antifreeze treated samples, as well as evidence of the consumption of water and unreacted cement at subfreezing temperatures

The in vivo evaluation of antinociceptive and antipyretic activities of Marrubium deserti De Noé infusion extract

The aim of this study was to evaluate the in vivo antinociceptive and antipyretic activities of Marrubium deserti De Noé infusion extract. Antinociceptive effect was evaluated by acetic acid induced writhing response, formalin-induced paw licking and the hot plat method in mice, while antipyretic activity was tested by brewer’s yeast induced pyrexia in rats. In each test, we examined the doses of 250, 500 and 1000 mg/kg body weight (bw) of the extract. The infusion extract produced dose-dependent antinociceptive effect against chemically and thermally induced nociceptive pain stimuli in mice. In acetic acid induced writhing test, the inhibition percentage of writhing response was 49.12% at 1000 mg/kg bw (p<0.001). This extract also significantly (p<0.001) inhibited the licking response of the formalin test at 1000 mg/kg bw in both the early phase (64.39%) and the late phase (70.75%). In the hot plate method, the infusion extract significantly (p<0.001) increased the reaction time to heat sensation to 58.21% at 1000 mg/kg bw Moreover, the extract possessed an excellent (p<0.001) antipyretic effect and even better than the reference drug. These findings indicate that M. deserti De Noé infusion extract possesses antinociceptive and antipyretic activities which could be due to the presence of bioactive compounds in this plant

The in vivo evaluation of antinociceptive and antipyretic activities of Marrubium deserti De Noé infusion extract

468-476The aim of this study was to evaluate the in vivo antinociceptive and antipyretic activities of Marrubium deserti De Noé infusion extract. Antinociceptive effect was evaluated by acetic acid induced writhing response, formalin-induced paw licking and the hot plat method in mice, while antipyretic activity was tested by brewer’s yeast induced pyrexia in rats. In each test, we examined the doses of 250, 500 and 1000 mg/kg body weight (bw) of the extract. The infusion extract produced dose-dependent antinociceptive effect against chemically and thermally induced nociceptive pain stimuli in mice. In acetic acid induced writhing test, the inhibition percentage of writhing response was 49.12% at 1000 mg/kg bw (p). This extract also significantly (p) inhibited the licking response of the formalin test at 1000 mg/kg bw in both the early phase (64.39%) and the late phase (70.75%). In the hot plate method, the infusion extract significantly (p) increased the reaction time to heat sensation to 58.21% at 1000 mg/kg bw Moreover, the extract possessed an excellent (p) antipyretic effect and even better than the reference drug. These findings indicate that M. deserti De Noé infusion extract possesses antinociceptive and antipyretic activities which could be due to the presence of bioactive compounds in this plant

Paralysie congénitale du IV révélée par une diplopie post chirurgie de la cataracte

Les causes de diplopie après une chirurgie de cataracte sont nombreuses. La paralysie congénitale du IV est peu fréquente et diagnostic difficile car elle peut rester longtemps compensée. Nous rapportons un cas qui souligne l'importance de penser, devant une diplopie, à une étiologie congénitale même à un âge avancé.Key words: Diplopie, paralysie du IV, cataract

Security and Privacy in RFID Systems

This PhD thesis is concerned with authentication protocols using portable lightweight devices such as RFID tags. these devices have lately gained a significant attention for the diversity of the applications that could benefit form their features, ranging from inventory systems and building access control, to medical devices. However, the emergence of this technology has raised concerns about the possible loss of privacy carrying such tags induce in allowing tracing persons or unveiling the contents of a hidden package. this fear led to the appearance of several organizations which goal is to stop the spread of RFID tags. We take a cryptographic viewpoint on the issue and study the extent of security and privacy that RFID-based solutions can offer. In the first part of this thesis, we concentrate on analyzing two original primitives that were proposed to ensure security for RFID tags. the first one, HB#, is a dedicated authentication protocol that exclusively uses very simple arithmetic operations: bitwise AND and XOR. HB# was proven to be secure against a certain class of man-in-the-middle attacks and conjectured secure against more general ones. We show that the latter conjecture does not hold by describing a practical attack that allows an attacker to recover the tag's secret key. Moreover, we show that to be immune against our attack, HB#'s secret key size has to be increased to be more than 15 000 bits. this is an unpractical value for the considered applications. We then turn to SQUASH, a message authentication code built around a public-key encryption scheme, namely Rabin's scheme. By mounting a practical key recovery attack on the earlier version of SQUASH, we show that the security of all versions of SQUASH is unrelated to the security of Rabin encryption function. The second part of the thesis is dedicated to the privacy aspects related to the RFID technology. We first emphasize the importance of establishing a framework that correctly captures the intuition that a privacy-preserving protocol does not leak any information about its participants. For that, we show how several protocols that were supported by simple arguments, in contrast to a formal analysis, fail to ensure privacy. Namely, we target ProbIP, MARP, Auth2, YA-TRAP, YA-TRAP+, O-TRAP, RIPP-FS, and the Lim-Kwon protocol. We also illustrate the shortcomings of other privacy models such as the LBdM model. The rest of the dissertation is then dedicated to our privacy model. Contrarily to most RFID privacy models that limit privacy protection to the inability of linking the identity of two participants in two different protocol instances, we introduce a privacy model for RFID tags that proves to be the exact formalization of the intuition that a private protocol should not leak any information to the adversary. the model we introduce is a refinement of Vaudenay's one that invalidates a number of its limitations. Within these settings, we are able to show that the strongest notion of privacy, namely privacy against adversaries that have a prior knowledge of all the tags' secrets, is realizable. To instantiate an authentication protocol that achieves this level of privacy, we use plaintext-aware encryption schemes. We then extend our model to the case of mutual authentication where, in addition to a tag authenticating to the reader, the reverse operation is also required

Phytochemical composition and pharmacological assessment of callus and parent plant of Asteriscus graveolens (Forssk.) Less. from Algerian Sahara

Purpose: To determine the phytochemical composition, acute toxicity, as well as analgesic and antiinflammatory properties of extracts of the aerial parts and callus cultures of Asteriscus graveolens.Methods: Different standard chemical tests were used for the screening of bioactive compounds in aqueous extracts of aerial parts of Asteriscus graveolens (PAE) and callus (CAE). High-performance liquid chromatography (HPLC) analysis was performed to identify the constituents of the glycosidic extract (GE). Acute oral toxicity test was carried out to ascertain the safety of the plant material. The analgesic and anti-inflammatory properties of the extracts were determined using acetic acid-induced writhing test and carrageenan-induced edema test, respectively.Results: Phytochemical analysis showed some differences in composition between the aerial parts and callus cultures. Results from HPLC analysis revealed the presence of 12 phenolic compounds in the GE of adult plants. In addition to being orally safe (no mortality), all extracts showed significant inhibition of acetic acid-induced chemical pain: PAE and GE produced 63 and 68 % reductions in pain, respectively, relative to 60.26 % pain reduction by aspirin. All extracts exerted potent anti-inflammatory effects, with PAE producing the highest effect (73 %) at a dose of 100 mg/mL.Conclusion: Asteriscus graveolens extracts possess potent pharmacological properties due to the presence of some phenolic compounds, especially flavonoids. These findings provide a scientific basis for the traditional uses of Asteriscus graveolens, and indicate that it is a potential source of antiinflammatory agents. Keywords: Acute toxicity, Anti-nociceptive, Anti-inflammatory, Aqueous extract, Callus, Flavonoid

Analgesic and anti-inflammatory properties of aqueous extract of Deverra scoparia Coss and Dur obtained from Tamanrasset, Algeria

Purpose: To determine the toxicity, anti-inflammatory and analgesic properties of Deverra scoparia Coss. & Dur. and the phenolic compounds involvedMethods: The aqueous extract of Deverra scoparia Coss. & Dur. was intra-gastrically administered at increasing doses (2, 4, 8, 12 and 16 g/kg) to mice of both sexes in order to study its acute toxicity. Analgesic activity was evaluated in mice and rats using acetic acid-induced writhing and formalin tests at doses of 250, 500 and 1000 mg/kg. Anti-inflammatory activity was assessed by carrageenan-induced paw oedema method, while the bioactive compounds in the extract were identified by high performance liquid chromatography (HPLC) analysis.Results: The extract (1000 mg/kg) produced significant inhibition in acetic acid-induced writhing (71.18 %) and formalin (83.58 %) tests; and 73.52 % reduction of carrageenan-induced rat paw oedema test (p < 0.001). HPLC analysis revealed the presence of two phenolic acids, viz, salicylic acid (21.81 mg/g dry weight) and rosmarinic acid (28.44 mg/g dry weight); and apigenin, a flavonoid aglycone (5.70 mg/g dry weight).Conclusion: These results indicate that the extract of Deverra scoparia Coss. & Dur. is non-toxic even at a dose of 16g/kg. The extract possesses significant analgesic and anti-inflammatory potential which may be due to the presence of phenolic compounds (apigenin, salicylic acid and rosmarinic acid).Keywords:  Deverra scoparia Coss. & Dur., Acute toxicity, Anti-inflammatory, Analgesic, HPLC, Phenolic compound

Anti-inflammatory and acute toxicity evaluation of aqueous infusion extract obtained from aerial parts of Marrubium deserti de Noé growing in Algeria

Background: Marrubium deserti de Noé, which is locally known as “Merriouet saharaui”, is widely used  in Algeria as a traditional treatment of many ailments. In this study, the anti-inflammatory and acute  toxicity of the aqueous infusion extract from aerial parts of Marrubium deserti were investigated.  Meanwhile, acute oral toxicity of M. deserti, as well as its anti-inflammatory activity is reported for the first time.Materials and Method: The anti-inflammatory activity was evaluated using carrageenin-induced paw oedema in mice at three different doses (250, 500 and 1000mg/kg body weight. Data were analyzed by one-way ANOVA followed by Dunnett’s t-test.Results: The aqueous infusion extract (250, 500 and 1000mg/kg body weight, orally administered, n=6) showed a significant (P<0.05) inhibition of carrageenin-induced mice paw oedema by 11.22, 20.73 and 44.03% respectively in the third hour when compared to the control group. Acetylsalicylic acid (ASA, 50mg/kg) as the positive control showed 32.08% inhibition. The oral LD50 values in mice were found to be greater than 2000mg/kg. The relatively high oral median lethal dose (>2000mg/kg) suggests that the aqueous infusion extract has a relatively low acute toxicity when taken orally for a single dose.Conclusions: The present study indicates that M. deserti has a significant anti-inflammatory effect and confirms its traditional use as a treatment of pain, yet it suggests further investigations to be carried out to determine the active chemical constituents.Keywords: Marrubium deserti, aqueous infusion extract, acute toxicity, anti-inflammatory activity