79 research outputs found

    Estimating generalized of global impacts to water quality on soil characteristics in basin of the Great Sebkha of Oran

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    In basin of the Great Sebkha of Oran, water deficit linked to climate semi-aridity has forced farmers to resort to the use of underground water of poor quality, which considered as the major cause of soil degradation. The alluvial aquifer waters are particularly characterized by higher relatively concentration in dissolved salts when compared them with other aquifers of the same system. Generally, the salinity of the water increases from upstream to downstream in the direction of the Sebkha (Boualla et al. in Water Supply 17(6):1801–1812, 2017). Assessment of soil quality has become the basic work for agricultural sustainable development. The aim of this paper is to evaluate soil properties in great Sebkha of Oran basin. Geo-referred soil samples were collected from ten-component analysis, and different soils were analysed for different physical and chemical attributes. Our study focuses on mineralogical analysis and geochemical prospecting using soil chemical data. Eleven indicators were selected to constitute data to assess the soil quality: sieve analysis, classification, cation exchange capacity, pH, soil organic matter, conductivity, gypsum, nature of the oxide content, nutrients (NO3_{3}-N, NH4_{4}-N, PO4_{4}-P), anions content (SO42^{2-}, Cl^{-}) and mineralogical analysis. Conclusively, process and mechanism of soil quality need deep research

    Experimental study of the effects of semi-elliptical defects on the API X52 pipeline and its reparation by welding

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    The aim of the studyis to investigate experimentallythe influence of the semi-elliptical defect on the steel of grade API 5L X52 pipeline and its reparation by welding operation to keep the safety of hydrocarbons transport network. The tests have been performed on the specimens with/without semi-elliptical defects by using two ratios a/c and a/t, where the defects issue on the piping systems wall is treated by using the welding operation, which focuses on the filling the defected surface as same thickness of the base wall of the pipeline after removing the defects. The decrease of ultimate stress is mainly evident depending on the size of crack, where they compared to the base metal results. The experimental results showed that the reliability of the welding operation is proved especially in the ratio a/c =1, which is similar to that found in automatically welded. It is proved that the ratio a/t = 0.2 curve exhibits similarity to the base metal curve and their elongation conforms to API standard of steel X52 grade. Clearly, corrosion defects cause degradation of mechanical property in the order of 44% to 50% depending on the ratio of 0 < a/c ≤1 and from 20% to 80%according to the second ration of 0 < a/t ≤0.8. The obtained results proved that the enhanced of mechanical properties by welding reaches to ultimate stress is 559 MPa for the ratio a/t = 0.2 and 531 MPa for the ratio a/t = 0.5. Finally, the experimental results provided that the impact of semi-elliptical defect has effects on the safety of piping systems where welding became as one of among solutions to repair the piping systems

    Etude Ethnobotanique Sur L’utilisation De Mentha Pulegium, Mentha Piperita Et Pelargonium Graveolens Au Nord Du Maroc (Taounate) Et Évaluation De Leur Pouvoir Antimicrobien

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    Traditional medicine has always occupied an important place in Moroccan traditions medication, Taounate region is concrete example. Thus, this survey aims to highlight the different uses of Mentha pulegium, Mentha piperita and Pelargonium graveolens in Taounate city during April month 2017, and to evaluate their antimicrobial potency against Staphylococcus epidermidis and Acinetobacter baumannii by microdilution method. A questionnaire was used with residents, herbalists and phytotherapists. The results showed that these three plants are used mainly for their therapeutic virtues; precisely against digestive disorders representing the most cited diseases for Mentha piperita (51%), respiratory diseases for Mentha pulegium (50%) and dermatological conditions for Pelargonium graveolens(44%). The majority of remedies are prepared by decoction (56%) from leaves (71%) and usually orally administered (68%) as herbal tea (58%). Cure rate is 41% with 53% health improvement. In addition, the essential oils of these studied plants exhibited strong inhibitory effect against all tested microorganisms with minimum inhibitory concentrations ranging from 0.01562% to 1% (v/v)

    Exercise in type 2 diabetes: to resist or to endure?

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    There is now evidence that a single bout of endurance (aerobic) or resistance exercise reduces 24 h post-exercise subcutaneous glucose profiles to the same extent in insulin-resistant humans with or without type 2 diabetes. However, it remains to be determined which group would benefit most from specific exercise protocols, particularly with regard to long-term glycaemic control. Acute aerobic exercise first accelerates translocation of myocellular glucose transporters via AMP-activated protein kinase, calcium release and mitogen-activated protein kinase, but also improves insulin-dependent glucose transport/phosphorylation via distal components of insulin signalling (phosphoinositide-dependent kinase 1, TBC1 domain family, members 1 and 4, Rac1, protein kinase C). Post-exercise effects involve peroxisome-proliferator activated receptor-γ coactivator 1α and lead to ATP synthesis, which may be modulated by variants in genes such as NDUFB6. While mechanisms of acute resistance-type exercise are less clear, chronic resistance training activates the mammalian target of rapamycin/serine kinase 6 pathway, ultimately increasing protein synthesis and muscle mass. Over the long term, adherence to rather than differences in metabolic variables between specific modes of regular exercise might ultimately determine their efficacy. Taken together, studies are now needed to address the variability of individual responses to long-term resistance and endurance training in real life

    Activation of AMP-activated protein kinase rapidly suppresses multiple pro-inflammatory pathways in adipocytes including IL-1 receptor-associated kinase-4 phosphorylation

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    yesInflammation of adipose tissue in obesity is associated with increased IL-1β, IL-6 and TNF-α secretion and proposed to contribute to insulin resistance. AMP-activated protein kinase (AMPK) regulates nutrient metabolism and is reported to have anti-inflammatory actions in adipose tissue, yet the mechanisms underlying this remain poorly characterised. The effect of AMPK activation on cytokine-stimulated proinflammatory signalling was therefore assessed in cultured adipocytes. AMPK activation inhibited IL-1β-stimulated CXCL10 secretion, associated with reduced interleukin-1 receptor associated kinase-4 (IRAK4) phosphorylation and downregulated MKK4/JNK and IKK/IκB/NFκB signalling. AMPK activation inhibited TNF-α-stimulated IKK/IκB/NFκB signalling but had no effect on JNK phosphorylation. The JAK/STAT3 pathway was also suppressed by AMPK after IL-6 stimulation and during adipogenesis. Adipose tissue from AMPKα1−/− mice exhibited increased JNK and STAT3 phosphorylation, supporting suppression of these distinct proinflammatory pathways by AMPK in vivo. The inhibition of multiple pro-inflammatory signalling pathways by AMPK may underlie the reported beneficial effects of AMPK activation in adipose tissue.British Heart Foundatio

    EMG-Normalised Kinase Activation during Exercise Is Higher in Human Gastrocnemius Compared to Soleus Muscle

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    In mice, certain proteins show a highly confined expression in specific muscle groups. Also, resting and exercise/contraction-induced phosphorylation responses are higher in rat skeletal muscle with low mitochondrial content compared to muscles with high mitochondrial content, possibly related to differential reactive oxygen species (ROS)-scavenging ability or resting glycogen content. To evaluate these parameters in humans, biopsies from soleus, gastrocnemius and vastus lateralis muscles were taken before and after a 45 min inclined (15%) walking exercise bout at 69% VO2max aimed at simultaneously activating soleus and gastrocnemius in a comparable dynamic work-pattern. Hexokinase II and GLUT4 were 46–59% and 26–38% higher (p<0.05) in soleus compared to the two other muscles. The type I muscle fiber percentage was highest in soleus and lowest in vastus lateralis. No differences were found in protein expression of signalling proteins (AMPK subunits, eEF2, ERK1/2, TBC1D1 and 4), mitochondrial markers (F1 ATPase and COX1) or ROS-handling enzymes (SOD2 and catalase). Gastrocnemius was less active than soleus measured as EMG signal and glycogen use yet gastrocnemius displayed larger increases than soleus in phosphorylation of AMPK Thr172, eEF2 Thr56 and ERK 1/2 Thr202/Tyr204 when normalised to the mean relative EMG-signal. In conclusion, proteins with muscle-group restricted expression in mice do not show this pattern in human lower extremity muscle groups. Nonetheless the phosphorylation-response is greater for a number of kinase signalling pathways in human gastrocnemius than soleus at a given activation-intensity. This may be due to the combined subtle effects of a higher type I muscle fiber content and higher training status in soleus compared to gastrocnemius muscle

    Chronic CaMKII inhibition blunts the cardiac contractile response to exercise training

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    Activation of the multifunctional Ca2+/calmodulin-dependent protein kinase II (CaMKII) plays a critical role modulating cardiac function in both health and disease. Here, we determined the effect of chronic CaMKII inhibition during an exercise training program in healthy mice. CaMKII was inhibited by KN-93 injections. Mice were randomized to the following groups: sham sedentary, sham exercise, KN-93 sedentary, and KN-93 exercise. Cardiorespiratory function was evaluated by ergospirometry during treadmill running, echocardiography, and cardiomyocyte fractional shortening and calcium handling. The results revealed that KN-93 alone had no effect on exercise capacity or fractional shortening. In sham animals, exercise training increased maximal oxygen uptake by 8% (p < 0.05) compared to a 22% (p < 0.05) increase after exercise in KN-93 treated mice (group difference p < 0.01). In contrast, in vivo fractional shortening evaluated by echocardiography improved after exercise in sham animals only: from 25 to 32% (p < 0.02). In inactive mice, KN-93 reduced rates of diastolic cardiomyocyte re-lengthening (by 25%, p < 0.05) as well as Ca2+ transient decay (by 16%, p < 0.05), whereas no such effect was observed after exercise training. KN-93 blunted exercise training response on cardiomyocyte fractional shortening (63% sham vs. 18% KN-93; p < 0.01 and p < 0.05, respectively). These effects could not be solely explained by the Ca2+ transient amplitude, as KN-93 reduced it by 20% (p < 0.05) and response to exercise training was equal (64% sham and 47% KN-93; both p < 0.01). We concluded that chronic CaMKII inhibition increased time to 50% re-lengthening which were recovered by exercise training, but paradoxically led to a greater increase in maximal oxygen uptake compared to sham mice. Thus, the effect of chronic CaMKII inhibition is multifaceted and of a complex nature

    Postexercise High-Fat Feeding Supresses p70S6K1 Activity in Human Skeletal Muscle.

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    PURPOSE: To examine the effects of reduced CHO but high post-exercise fat availability on cell signalling and expression of genes with putative roles in regulation of mitochondrial biogenesis, lipid metabolism and muscle protein synthesis (MPS). METHODS: Ten males completed a twice per day exercise model (3.5 h between sessions) comprising morning high-intensity interval (HIT) (8 x 5-min at 85% VO2peak) and afternoon steady-state (SS) running (60 min at 70% VO2peak). In a repeated measures design, runners exercised under different isoenergetic dietary conditions consisting of high CHO (HCHO: 10 CHO, 2.5 Protein and 0.8 Fat g.kg per whole trial period) or reduced CHO but high fat availability in the post-exercise recovery periods (HFAT: 2.5 CHO, 2.5 Protein and 3.5 Fat g.kg per whole trial period). RESULTS: Muscle glycogen was lower (P<0.05) at 3 (251 vs 301 mmol.kgdw) and 15 h (182 vs 312 mmol.kgdw) post-SS exercise in HFAT compared to HCHO. AMPK-α2 activity was not increased post-SS in either condition (P=0.41) though comparable increases (all P<0.05) in PGC-1α, p53, CS, Tfam, PPAR and ERRα mRNA were observed in HCHO and HFAT. In contrast, PDK4 (P=0.003), CD36 (P=0.05) and CPT1 (P=0.03) mRNA were greater in HFAT in the recovery period from SS exercise compared with HCHO. p70S6K activity was higher (P=0.08) at 3 h post-SS exercise in HCHO versus HFAT (72.7 ± 51.9 vs 44.7 ± 27 fmol.min mg). CONCLUSION: Post-exercise high fat feeding does not augment mRNA expression of genes associated with regulatory roles in mitochondrial biogenesis though it does increase lipid gene expression. However, post-exercise p70S6K1 activity is reduced under conditions of high fat feeding thus potentially impairing skeletal muscle remodelling processes

    Hypoxia, AMPK activation and uterine artery vasoreactivity

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    This is the author accepted manuscript. The final version is available from Wiley via http://dx.doi.org/10.1113/JP270995Genes near adenosine monophosphate-activated protein kinase-α1 (PRKAA1) have been implicated in the greater uterine artery (UtA) blood flow and relative protection from fetal growth restriction seen in altitude-adapted Andean populations. Adenosine monophosphate-activated protein kinase (AMPK) activation vasodilates multiple vessels but whether AMPK is present in UtA or placental tissue and influences UtA vasoreactivity during normal or hypoxic pregnancy remains unknown. We studied isolated UtA and placenta from near-term C57BL/6J mice housed in normoxia (n = 8) or hypoxia (10% oxygen, n = 7-9) from day 14 to day 19, and placentas from non-labouring sea level (n = 3) or 3100 m (n = 3) women. Hypoxia increased AMPK immunostaining in near-term murine UtA and placental tissue. RT-PCR products for AMPK-α1 and -α2 isoforms and liver kinase B1 (LKB1; the upstream kinase activating AMPK) were present in murine and human placenta, and hypoxia increased LKB1 and AMPK-α1 and -α2 expression in the high- compared with low-altitude human placentas. Pharmacological AMPK activation by A769662 caused phenylephrine pre-constricted UtA from normoxic or hypoxic pregnant mice to dilate and this dilatation was partially reversed by the NOS inhibitor l-NAME. Hypoxic pregnancy sufficient to restrict fetal growth markedly augmented the UtA vasodilator effect of AMPK activation in opposition to PE constriction as the result of both NO-dependent and NO-independent mechanisms. We conclude that AMPK is activated during hypoxic pregnancy and that AMPK activation vasodilates the UtA, especially in hypoxic pregnancy. AMPK activation may be playing an adaptive role by limiting cellular energy depletion and helping to maintain utero-placental blood flow in hypoxic pregnancy.Funding for these studies was provided by the Wellcome Trust (084804/2/08/Z) to G.J.B., the British Heart Foundation and the Wellcome Trust to D.A.G., the Biotechnology and Biological Sciences Research Council (BBSRC) to A.L.F., a UK Wellcome Trust Programme Grant (WT081195MA) to A.M.E. and A.D.M., a BBSRC studentship and in vivo skills award to J.S.H., a National Health Medical Research Council and Centre for Trophoblast Research fellowship to A.N.S.-P., and a NIH RO1 grant (HLBI-079647) to L.G.M. along with sabbatical support from Wake Forest University
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