Sample records for mg kg-1 increased

  1. Rapacuronium 2.0 or 2.5 mg kg(-1) for rapid-sequence induction : comparison with succinylcholine 1.0 mg kg(-1)

    Blobner, M; Mirakhur, RK; Wierda, JMKH; Wright, PMC; Olkkola, KT; Debaene, B; Pendeville, P; Engbaek, J; Rietbergen, H; Sparr, HJ


    The purpose of this nine-centre study in 602 patients was to show that the frequency of acceptable intubating conditions after rapacuronium 2.0 or 2.5 mg kg(-1) is not more than 10% lower than the frequency after succinylcholine 1.0 mg kg(-1) during rapid-sequence induction of anaesthesia with fenta

  2. Sugammadex 4.0 mg kg-1 reversal of deep rocuronium-induced neuromuscular blockade

    Yu, Buwei; Wang, Xiangrui; Hansen, Søren Helbo


    Objective: Maintenance of deep Neuro Muscular Blockade (NMB) until the end of surgery may be beneficial in some surgical procedures. The selective relaxant binding agent sugammadex rapidly reverses deep levels of rocuronium-induced NMB. The purpose of this study was to evaluate the efficacy...... and safety of sugammadex 4.0 mg kg-1 for reversal of deep rocuronium-induced NMB in Chinese and Caucasian patients. Methods: This was an open-label, multicenter, prospective Phase III efficacy study in adult American Society of Anesthesiologists Class 1-3 patients scheduled for surgery under general...... anesthesia and requiring deep NMB. All patients received intravenous propofol and opioids for induction and maintenance of anesthesia, and a single intubation dose of rocuronium 0.6 mg/kg, with maintenance doses of 0.1-0.2 mg/kg as required. Sugammadex 4.0 mg/kg was administered after the last dose...

  3. Efficacy, safety and pharmacokinetics of sugammadex 4 mg kg-1 for reversal of deep neuromuscular blockade in patients with severe renal impairment.

    Panhuizen, I F; Gold, S J A; Buerkle, C; Snoeck, M M J; Harper, N J N; Kaspers, M J G H; van den Heuvel, M W; Hollmann, M W


    This study evaluated efficacy and safety of sugammadex 4 mg kg(-1) for deep neuromuscular blockade (NMB) reversal in patients with severe renal impairment (creatinine clearance [CLCR] Sugammadex 4 mg kg(-1) was administered at 1-2 post-tetanic counts for reversal of rocuronium NMB. Primary efficacy variable was time from sugammadex to recovery to train-of-four (T4/T1) ratio 0.9. Equivalence between groups was demonstrated if two-sided 95% CI for difference in recovery times was within -1 to +1 min interval. Pharmacokinetics of rocuronium and overall safety were assessed. The intent-to-treat group comprised 67 patients (renal n=35; control n=32). Median (95% CI) time from sugammadex to recovery to T4/T1 ratio 0.9 was 3.1 (2.4-4.6) and 1.9 (1.6-2.8) min for renal patients vs controls. Estimated median (95% CI) difference between groups was 1.3 (0.6-2.4) min; thus equivalence bounds were not met. One control patient experienced acceleromyography-determined NMB recurrence, possibly as a result of premature sugammadex (4 mg kg(-1)) administration, with no clinical evidence of NMB recurrence observed. Rocuronium, encapsulated by Sugammadex, was detectable in plasma at day 7 in 6 patients. Bioanalytical data for sugammadex were collected but could not be used for pharmacokinetics. Sugammadex 4 mg kg(-1) provided rapid reversal of deep rocuronium-induced NMB in renal and control patients. However, considering the prolonged sugammadex-rocuronium complex exposure in patients with severe renal impairment, current safety experience is insufficient to support recommended use of sugammadex in this population. NCT00702715. © The Author 2015. Published by Oxford University Press on behalf of the British Journal of Anaesthesia. All rights reserved. For Permissions, please email:

  4. Postoperative impairment of motor function at train-of-four ratio ≥0.9 cannot be improved by sugammadex (1 mg kg-1).

    Baumüller, E; Schaller, S J; Chiquito Lama, Y; Frick, C G; Bauhofer, T; Eikermann, M; Fink, H; Blobner, M


    A train-of-four ratio (TOFR) ≥0.9 measured by quantitative neuromuscular monitoring is accepted as an indication of sufficient neuromuscular recovery for extubation, even though many postsynaptic acetylcholine receptors may still be inhibited. We investigated whether antagonism with sugammadex after spontaneous recovery to TOFR≥0.9 further improves muscle function or subjective well-being. Following recovery to TOFR≥0.9 and emergence from anaesthesia, 300 patients randomly received either sugammadex 1.0 mg kg(-1) or placebo. Fine motor function (Purdue Pegboard Test) and maximal voluntary grip strength were measured before and after surgery (before and after test drug administration). At discharge from the postanaesthesia care unit, well-being was assessed with numerical analogue scales and the Quality-of-Recovery Score 40 (QoR-40). Patients' fine motor function [6 (sd 4) vs 15 (3) pegs (30 s)(-1), Psugammadex or placebo, motor function was significantly improved in both groups but did not reach the preoperative level. There was no difference between groups at any time. Global well-being was unaffected (QoR-40: placebo, 174 vs 185; sugammadex, 175 vs 186, P>0.05). Antagonizing rocuronium at TOF≥0.9 with sugammadex 1.0 mg kg(-) (1) did not improve patients' motor function or well-being when compared with placebo. Our data support the view that TOFR≥0.9 measured by electromyography signifies sufficient recovery of neuromuscular function. The trial is registered at (NCT01101139). © The Author 2014. Published by Oxford University Press on behalf of the British Journal of Anaesthesia. All rights reserved. For Permissions, please email:

  5. Children and parental anxiolysis in paediatric ambulatory surgery: a randomized controlled study comparing 0.3 mg kg-1 midazolam to tablet computer based interactive distraction.

    Marechal, C; Berthiller, J; Tosetti, S; Cogniat, B; Desombres, H; Bouvet, L; Kassai, B; Chassard, D; de Queiroz Siqueira, M


    The operating theatre, anaesthesia induction and separation from parents create fear and anxiety in children. Anxiety leads to adverse behavioral changes appearing and sometimes persisting during the postoperative period. Our aim was to compare the effects of midazolam (0.3 mg kg(-)(1): MDZ) for premedication with age-appropriate tablet game apps (TAB) on children anxiety during and after ambulatory surgery. A randomized controlled trial was conducted from May 16th, 2013 to March 25th, 2014 at the Children Hospital of Lyon. The primary outcome of this study was the change in m-YPAS score at the time of anaesthetic mask induction. Anxiety was also assessed in the waiting surgical area, at the time of separation with parents and when back in the ambulatory surgery ward. One hundred and eighteen patients aged four-11 yr were recruited, 60 in the TAB Group and 58 in the MDZ Group. Main endpoint was missing for three patients from the MDZ Group. At the time of mask induction, there was no significant difference between MDZ and TAB Group for the m-YPAS score (40.5 (18.6) vs 41.8 (20.7), P = 0.99). There was no significant correlation between m-YPAS score and its evolution over the four period of time between subjects. We were not able to show whether TAB is superior to MDZ to blunt anxiety in children undergoing ambulatory surgery. TAB is a non-pharmacological tool which has the capacity in reducing perioperative stress without any sedative effect in this population. NCT 02192710. © The Author 2017. Published by Oxford University Press on behalf of the British Journal of Anaesthesia. All rights reserved. For Permissions, please email:

  6. Atazanavir increases the plasma concentrations of 1200 mg raltegravir dose.

    Krishna, Rajesh; East, Lilly; Larson, Patrick; Valiathan, Chandni; Deschamps, Kathleen; Luk, Julie Ann; Bethel-Brown, Crystal; Manthos, Helen; Brejda, John; Gartner, Michael


    Raltegravir is a human immunodeficiency virus (HIV)-1 integrase strand transfer inhibitor currently marketed at a dose of 400 mg twice-daily (b.i.d.). Raltegravir 1200 mg once-daily (q.d.) (investigational q.d. formulation of 2 × 600 mg tablets; q.d. RAL) was found to be generally well tolerated and non-inferior to the marketed 400 mg b.i.d. dose at 48 weeks in a phase 3 trial. Since raltegravir is eliminated mainly by metabolism via a uridine diphosphate glucuronosyltransferase (UGT) 1A1-mediated glucuronidation pathway, co-administration of UGT1A1 inhibitors may increase the plasma levels of q.d. RAL. To assess this potential, the drug interaction of 1200 mg raltegravir using atazanavir, a known UGT1A1 inhibitor, was studied. An open-label, randomized, 2-period, fixed-sequence phase 1 study was performed in adult healthy male and female (non-childbearing potential) subjects ≥ 19 and ≤ 55 years of age, with a body mass index (BMI) ≥ 18.5 and ≤ 32.0 kg/m(2) . Subjects (n = 14) received a single oral dose of 1200 mg raltegravir in period 1. After a washout period of at least 7 days, the subjects received oral doses of 400 mg atazanavir q.d. for 9 consecutive days, with a single oral dose of 1200 mg raltegravir co-administered on day 7 of period 2. Serial blood samples were collected for 72 h following raltegravir dosing and analysed using a validated bioanalytical method to quantify raltegravir plasma concentrations. Co-administration with atazanavir yielded GMRs (90% CIs) for raltegravir AUC0-∞ , Cmax and C24 of 1.67 (1.34, 2.10), 1.16 (1.01, 1.33) and 1.26 (1.08, 1.46), respectively. There was no effect of raltegravir on serum total bilirubin. In contrast, atazanavir increased the mean bilirubin by up to 200%, an effect that was preserved in the atazanavir/raltegravir treatment group. Administration of single q.d. RAL alone and co-administered with multiple oral doses of atazanavir were generally well tolerated in healthy subjects. The results show that

  7. Single doses of ivermectin 400 micrograms/kg-1: the most effective dosage in bancroftian filariasis.

    Moulia-Pelat, J P; Glaziou, P; Nguyen, L N; Cartel, J L


    Forty-three Wuchereria bancrofti carriers were given four successive semi-annual single doses of ivermectin 100 (IVER 100). The geometric mean microfilaremia (mf) recurrence percentage as compared to the pre-initial treatment mf level was 35%, 21%, 17% and 17% at 6, 12, 18 and 24 months, respectively. However, the recurrence of mf 6 months after the fourth treatment remained high in several individuals: 15 have been considered as 'bad responders' and 28 as 'good responders' individuals. At month 24 (M 24), they were randomly allocated into 2 groups. A first group was treated with a fifty and a sixth dose of IVER 100, at M24 and M30, respectively; the second one was treated, at the same time, with single doses of IVER 400 (IVER 400). At M 36, the mf recurrence percentage (mf M36/mf M0) was significantly higher in patients treated with IVER 100 than IVER 400 (11% vs 1%, p < 10(-4). From the group IVER 100, 6 out of the 8 'bad responders' remained 'bad responders' whereas there were none of the 7 in the group IVER 400. Moreover, there were only 2 more patients in the group IVER 100 showing sustained complete zero mf, whereas they were 13 in the group IVER 400. Single doses of IVER 400 were effective on 'bad responders'; IVER 400 must be recommended for semi-annual mass treatment in bancroftian filariasis.

  8. Effects of the combination of decitabine and homoharringtonine in SKM-1 and Kg-1a cells.

    Geng, Suxia; Yao, Han; Weng, Jianyu; Tong, Jiaqi; Huang, Xin; Wu, Ping; Deng, Chengxin; Li, Minming; Lu, Zesheng; Du, Xin


    The methylation inhibitor decitabine (DAC) has great therapeutic value for myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML). However, DAC monotherapy is associated with relatively low rates of overall response and complete remission. Previous studies have shown promising results for combination treatment regimens including DAC. Homoharringtonine (HHT), an alkaloid from Chinese natural plants and Cephalotaxus, has demonstrated potential for leukemia treatment. Our studies have suggested that the combination of DAC and HHT has synergistic effects for inhibiting the viability of SKM-1 and Kg-1a cells. This combination leads to enhanced inhibition of colony formation and apoptosis induction compared with DAC alone in SKM-1 but not Kg-1a cells. Only high-dose DAC and HHT significantly up-regulate caspase-3 and caspase-9 and inhibit BCL-XL in the SKM-1 cell line. The combined effects of DAC plus HHT on apoptosis may not only depend on regulation of the apoptosis-related genes we examined but others as well. HHT had no demethylation effects, and HHT in combination with DAC had no enhanced effects on hypomethylation and DNMT1, DNMT3A and DNMT3B mRNA expression in SKM-1 cells. Overall, these results suggest that DAC used in combination with HHT may have clinical potential for MDS treatment.

  9. 白藜芦醇增强TRAIL对人髓系白血病KG-1a细胞的细胞毒作用%Resveratrol enhances cytotoxicity of TRAIL to human promyloblastic leukemia KG-1a cells

    胡亮杉; 孙茂本; 曾雅丽; 李玉华; 邓兰; 郭坤元


    目的:观察白藜芦醇作用前后TRAIL对人髓系白血病KG-1a细胞的细胞毒作用的变化.方法:流式细胞仪检测KG-1a细胞表面CD34 和CD38的表达,二甲氧唑黄(XTT)细胞增殖及细胞毒性检测试剂盒检测白藜芦醇作用前后TRAIL对KG-1a细胞增殖的影响,AnnexinV-FITC/PI染色流式细胞仪检测细胞凋亡变化.流式细胞仪检测白藜芦醇作用前后KG-1a细胞表面TRAIL死亡受体表达变化.结果:人髓系白血病KG-1a细胞 CD34+CD38-占(58.67±2.87)%,10~1 000 ng/ml 的TRAIL对KG-1a细胞增殖无明显影响,但对白藜芦醇作用后的KG-1a细胞的增殖有明显抑制作用,白藜芦醇能促进TRAIL诱导KG-1a细胞凋亡,并能上调KG-1a细胞表面TRAIL死亡受体DR5的表达.结论:白藜芦醇能增强TRAIL对人髓系白血病KG-1a细胞的细胞毒作用,其机制可能与白藜芦醇上调KG-1a细胞表面TRAIL死亡受体DR5的表达有关.%Objective :To explore the cytotoxicity of TRAIL to human acute promyeloblastic leukemia KG-1a cells treated with resvera trol .Methods :The expression of CD34 and CD38 on the Surface of KG-1 cells was detected by flow cytometry ;The effects of various concentration TRAIL on proliferation of KG-1a cells treated with or without resveratrol were analyzed by XTT cell proliferation and cytotoxicity assay kit ;The changes of apoptosis in KG-1a cells treated with or without resveratrol induced by TRAIL were detected by flow cytometry through the staining of AnnexinV-FITC /PI ;The effects of resveratrol on the expression of DR4/5 on the surface of KG-1a cells were detected by flow cytometry .Results :The CD34+ CD38- percent age of KG-1a cells was (58 .67±2 .87 )% ;10-1 000 ng/ml of TRAIL had no effects on the proliferation of KG-1a cells ,while could inhibit the proliferation of KG-1a cells treated with resveratrol ;Moreover ,resveratrol could enhance the apoptosis of KG-1a cells induced by TRAIL and up-regulate the expression of TIRAIL death receptors DR5

  10. Improved efficacy of intramuscular weekly administration of clodronate 200 mg (100 mg twice weekly) compared with 100 mg (once weekly) for increasing bone mineral density in postmenopausal osteoporosis.

    Frediani, Bruno; Bertoldi, Ilaria; Pierguidi, Serena; Nicosia, Antonella; Picerno, Valentina; Filippou, Georgios; Cantarini, Luca; Galeazzi, Mauro


    Clodronate is a bisphosphonate used for the treatment of postmenopausal osteoporosis and all conditions characterized by excess bone resorption. We have previously reported that intramuscular (IM) therapy with clodronate at a dose of 100 mg/week displays significant effects on bone mineral density (BMD) although a plateau effect is observed after 1 year of treatment. Previous reports indicate that the densitometric effects of bisphosphonates directly correlate with the drug dosage and suggest that using IM clodronate at doses higher than 100 mg/week may result in improved efficacy. However, to the best of our knowledge, this has never been proved. The primary endpoint of the study was the effect on BMD of IM clodronate 100 mg once weekly or 100 mg twice weekly in patients with postmenopausal osteoporosis. The incidence of non-traumatic vertebral fractures and adverse events was also reported. The present study was a randomized, open-label, parallel-group trial conducted between January 2007 and December 2009 in the Osteoporosis and Osteoarticular Instrumental Diagnosis Centre (University of Siena, Siena, Italy). The study involved 60 women, aged 57-78 years, with a history of postmenopausal osteoporosis for more than 5 years. Patients were randomized to receive IM clodronate 100 mg once weekly (Group A, 30 patients) or 100 mg twice weekly (Group B, 30 patients), for 2 years. Significant increases compared with baseline in BMD were observed for both groups at 1 and 2 years, with significantly higher increases for Group B compared with Group A. Group B displayed a BMD increase (± SD) at the lumbar spine of +4.0 % (± 2.1) and +5.9 % (± 2.0) at 1 and 2 year(s), respectively, compared with +2.8 % (± 1.7) and +3.5 % (± 2.2), respectively, observed for Group A. Similarly, Group B showed better performance compared with Group A for BMD increase at the femoral neck, with an observed increase of +3.5 % (± 1.7) and +5.4 % (± 1.8) at 1 and 2 year(s), respectively

  11. TGF-β1对白血病KG-1细胞株Gli1表达的影响%Effect of TGF-β1 on Gli1 expression in KG-1 cell line

    李哲; 潘静


    Objective To prove that there was cross talk between Hh signaling pathway and TGF-β signaling pathway in KG-1 cells line. Methods (1) KG-1 cells were treated with 0. 1 ng/mL,l ng/mL,and 10 ng/mL TGF-β1 for 6 h,12 h,and 24 h respectively. Cells were collected after stimulation. Total mRNA was extracted. Glil expression was detected by real-time PCR. (2) KG-1 cells were treated with 5 ng/mL TGFβ1 and 5 ng/mL TGF-β1 +5 μmol SIS3 respectively for 24h. Cells were collected after stimulation. Total mRNA was extracted. Glil expression was detected. Results (1) When 1- 10 ng/mL TGF-β1 acted on the KG-1 cells respectively for 6 h, 12 h and 24 h, significant reduction of Glil mRNA in response to TGF-β1 was observed in KG-1 cells, emerging at 12 h and lasting at least 24 h,lower than that of the control group. (2) When 5 ng/mL TGF-β1 and 5 ng/mL TGF-β1 +5 μmol SIS3 acted on the KG-1 cells respectively for 24 h respectively,Glil expression of mRNA of control group was higher than that of TGF-β1 group, while much lower than that of TGF-β1 +SIS3 group. Conclusion TGF-β1significantly decreased Glil expression in KG-1 cells. Glil induction in KG-1 cells by TGF-β1 was a Smad3-dependent manner. This effect was independent from the Ptch/Smo axis.%目的 证明在白血病KG-1细胞株中存在TGF-β信号通路对Gli的调控作用.方法 (1)用0.1、1、10 ng/mL TGF-β1分别作用于KG-1细胞,时间分别为6、12、24 h.处理结束后收集细胞,提取mRNA,检测Gli1的表达.(2)5 ng/mL TGF-β1、5 ng/mL TGF-β1联合5 μmol SIS3分别作用于KG-1细胞24 h.处理结束后收集细胞,提取mRNA,检测Gli1的表达.结果 (1)1~10 ng/mL TGF-β1分别作用于KG-1细胞6、12、24 h,从12 h起并至少持续至24 h,其Gli1的mRNA表达较对照组明显减少;(2)5 ng/mL TGF-β1、5ng/mL TGF-β1联合5 μmol SIS3分别作用于KG-1细胞24 h,其Gli1的mRNA表达与对照组比较:5 ng/mL TGF-β1组较对照组降低,而5 ng/mL TGF-β1联合5 μmol SIS3组较

  12. Analysis of EET on Ca increasing the melting point of Mg17Al12 phase


    The present investigation showed that the additions of Ca to the alloy AZ91 were mainly dissolved into the Mg17Al12 phase and increased its melting point and thermal stability, which would have great effects on the high- temperature properties of AZ91 alloy. The empirical electron theory (EET) of solid and molecules was used to calculate the valence electron structures (VES) of Mg17Al12 intermetallic compound with and without Ca addition. The results showed that Ca dissolving in Mg17Al12 phase increased the strength of bonds that control the thermal stability of Mg17Al12 phase. Additions of Ca also made the distribution of the valence electrons on the dominant bond network more uniform in the whole unit cell of Mg17Al12. The theoretical conclusions well account for the experimental results.

  13. Mechanism of scandium influence on strength and heat resistance increase in Al-Mg alloys

    Drits, M.E.; Pavlenko, S.G.; Toropova, L.S.; Bykov' , Yu.G.; Ber, L.B. (AN SSSR, Moscow. Inst. Metallurgii)


    An attempt is made to study the strengthening nature in the Al-Mg-Sc alloy system. The problems of the temperature stability of the non-crystallized structure of the Al-6.5% Ng alloy and the nature of secondary extractions in these alloys caused by scandium presence, are studied. The alteration of the fluidity limit of the Al-6.5% Mg-Se alloys depending on the annealing temperature for various types of intermediate products is shown. Doping of the Al-6.5% Mg alloy with scandium brings about a considerable increase of strength properties, as a result of formation of the ScAl/sub 3/ phase.

  14. Magnetic gold nanoparticles: synthesis, characterization and its application in the delivery of FITC into KG-1 cells.

    Hao, Yuzhi; Song, Steven; Yang, Xiaoyan; Xing, James; Chen, Jie


    In this article, we report a new method-a sonication method to disperse iron oxide nanoparticles into smaller nanoparticles and make gold ions absorb onto the surface or trapped in the micropores of the iron oxide nanoparticles using sonication action. By using quick reduction of ascorbic acid and post-HCI solution treatment, gold covered magnetic nanoparticles (mGNPs) with spherical morphology and uniform size were synthesized in a water solution. The size of the mGNPs was found to be 20-30 nm. Some ideal mGNPs possessed a core-shell structure. The mGNPs were non-cytotoxic and mGNP-fluorescein isothiocyanate (FITC) can enter KG-1 cells when driven by an external magnetic force, which was confirmed by confocal imaging. The confocal image also showed the FITC inside the KG-1 cells was near the nucleus. The fluorescein isothiocyanate (FITC) delivery efficiency is about 100% according to the flow cytometry results.

  15. Post-fusion treatment with MG132 increases transcription factor expression in somatic cell nuclear transfer embryos in pigs.

    You, Jinyoung; Lee, Joohyeong; Kim, Jinyoung; Park, Junhong; Lee, Eunsong


    The objective of this study was to examine the effect of post-fusion treatment of somatic cell nuclear transfer (SCNT) oocytes with the proteasomal inhibitor MG132 on maturation promoting factor (MPF) activity, nuclear remodeling, embryonic development, and gene expression of cloned pig embryos. Immediately after electrofusion, SCNT oocytes were treated with MG132 and/or caffeine for 2 hr, vanadate for 0.5 hr, or vanadate for 0.5 hr followed by MG132 for 1.5 hr. Of the MG132 concentrations tested (0-5 microM), the 1 microM concentration showed a higher rate of blastocyst formation (25.9%) than 0 (14.2%), 0.5 (16.9%), and 5 microM (16.9%). Post-fusion treatment with MG132, caffeine, and both MG132 and caffeine improved blastocyst formation (22.1%, 21.4%, and 24.4%, respectively), whereas vanadate treatment inhibited blastocyst formation (6.5%) compared to the control (11.1%). When examined 2 hr after fusion and 1 hr after activation, MPF activity remained at a higher (P fusion with caffeine and/or MG132, but it was decreased by vanadate. The rate of oocytes showing premature chromosome condensation was not altered by MG132 but was decreased by vanadate treatment. In addition, formation of single pronuclei was increased by MG132 compared to control and vanadate treatment. MG132-treated embryos showed increased expression of POU5F1, DPPA2, DPPA3, DPPA5, and NDP52l1 genes compared to control embryos. Our results demonstrate that post-fusion treatment of SCNT oocytes with MG132 prevents MPF degradation and increases expression of transcription factors in SCNT embryos, which are necessary for normal development of SCNT embryos.

  16. Salinomycin overcomes ABC transporter-mediated multidrug and apoptosis resistance in human leukemia stem cell-like KG-1a cells

    Fuchs, Dominik [Research Group Molecular Neuro-Oncology, German Cancer Research Center, Im Neuenheimer Feld 280, D-69120 Heidelberg (Germany); Institute of Immunology, University of Heidelberg, Im Neuenheimer Feld 305, D-69120 Heidelberg (Germany); Daniel, Volker; Sadeghi, Mahmoud; Opelz, Gerhard [Institute of Immunology, University of Heidelberg, Im Neuenheimer Feld 305, D-69120 Heidelberg (Germany); Naujokat, Cord, E-mail: [Institute of Immunology, University of Heidelberg, Im Neuenheimer Feld 305, D-69120 Heidelberg (Germany)


    Leukemia stem cells are known to exhibit multidrug resistance by expression of ATP-binding cassette (ABC) transporters which constitute transmembrane proteins capable of exporting a wide variety of chemotherapeutic drugs from the cytosol. We show here that human promyeloblastic leukemia KG-1a cells exposed to the histone deacetylase inhibitor phenylbutyrate resemble many characteristics of leukemia stem cells, including expression of functional ABC transporters such as P-glycoprotein, BCRP and MRP8. Consequently, KG-1a cells display resistance to the induction of apoptosis by various chemotherapeutic drugs. Resistance to apoptosis induction by chemotherapeutic drugs can be reversed by cyclosporine A, which effectively inhibits the activity of P-glycoprotein and BCRP, thus demonstrating ABC transporter-mediated drug resistance in KG-1a cells. However, KG-1a are highly sensitive to apoptosis induction by salinomycin, a polyether ionophore antibiotic that has recently been shown to kill human breast cancer stem cell-like cells and to induce apoptosis in human cancer cells displaying multiple mechanisms of drug and apoptosis resistance. Whereas KG-1a cells can be adapted to proliferate in the presence of apoptosis-inducing concentrations of bortezomib and doxorubicin, salinomycin does not permit long-term adaptation of the cells to apoptosis-inducing concentrations. Thus, salinomycin should be regarded as a novel and effective agent for the elimination of leukemia stem cells and other tumor cells exhibiting ABC transporter-mediated multidrug resistance.

  17. Platelet response to increased aspirin dose in patients with persistent platelet aggregation while treated with aspirin 81 mg.

    Gengo, Fran; Westphal, Erica S; Rainka, Michelle M; Janda, Maria; Robson, Matthew J; Hourihane, J Maurice; Bates, Vernice


    This study demonstrates that patients who are taking 81 mg of aspirin and are nonresponsive benefit from a dose of 162 mg or greater vs a different antiplatelet therapy. We identified 100 patients who were nonresponsive to aspirin 81 mg via whole blood aggregometry and observed how many patients became responsive at a dose of 162 mg or greater. Platelet nonresponsiveness was defined as >10 Ω of resistance to collagen 1 µg/mL and/or an ohms ratio of collagen 1 µg/mL to collagen 5 µg/mL >0.5 and/or >6 Ω to arachidonate. Borderline response was defined as an improvement in 1 but not both of the above criteria. Of the initial 100 patients who were nonresponsive to an aspirin dose of 81 mg, 79% became responsive at a dose of 162 mg or >162 mg. Only 6% did not respond to any increase in dose. We believe that patients treated with low-dose aspirin who have significant risk for secondary vascular events should be individually assessed to determine their antiplatelet response. Those found to have persistent platelet aggregation despite treatment with 81 mg of aspirin have a higher likelihood of obtaining an adequate antiplatelet response at a higher aspirin dose.

  18. Increased postprandial energy expenditure in obese women after peroral K- and Mg-phosphate.

    Jaedig, S; Lindgärde, F; Arborelius, M


    Energy expenditure (EE) was studied in 15 obese (BMI > 27.5, median 29.2) and 15 lean (BMI magnesium-phosphate to glucose increases the postprandial thermogenesis in obese postmenopausal women, but not in lean ones.

  19. Long-term efficacy of single-dose treatment with 400 of ivermectin in bancroftian filariasis: results at one year.

    Moulia-Pelat, J P; Glaziou, P; Nguyen, L N; Chanteau, S; Martin, P M; Cartel, J L


    In April 1992, a safety trial was performed with a single dose of ivermectin 400 (IVER 400). In 37 bancroftian filariasis carriers, 6 and 12 months after IVER 400 treatment, the microfilaremia recurrences were 3.2% and 13.5%, respectively. As compared to results from other studies with diethylcarbamazine and IVER at different dosages and periodicities, the dosage of IVER 400 seems the most effective; but a yearly intake might not be sufficient.

  20. Defective maintenance of intracellular Ca2+ homeostasis is linked to increased muscle fatigability in the MG29 null mice


    Mitsugumin 29 (MG29) is a transmembrane protein that is normally found in the triad junction of skeletal muscle. Our previous studies have shown that targeted deletion of mg29 from the skeletal muscle resulted in abnormality of the triad junction structure, and also increased susceptibility to muscle fatigue. To elucidate the basis of these effects, we investigated the properties of Ca2+-uptake and -release in toxin-skinned Extensor Digitorium Longus (EDL) muscle fibers from control and mg29 knockout mice. Compared with the control muscle, submaximal Ca2+-uptake into the sarcoplasmic reticulum (SR) was slower and the storage of Ca2+ inside the SR was less in the mutant muscle, due to increased leakage process-of Ca2+ movement across the SR. The leakage pathway is associated with the increased sensitivity of Ca2+/caffeine -induced Ca2+ release to myoplasmic Ca2+. Therefore, the increased fatigability of mutant EDL muscles can result from a combination of a slowing of Ca2+ uptake, modification of Ca2+-induced Ca2+ release (CICR), and a reduction in total SR Ca2+ content.

  1. Increasing the gravimetric energy density of organic based secondary battery cathodes using small radius cations (Li+ and Mg2+).

    Hernández-Burgos, Kenneth; Rodríguez-Calero, Gabriel G; Zhou, Weidong; Burkhardt, Stephen E; Abruña, Héctor D


    One of the major challenges in electrochemical energy storage (EES) is increasing the gravimetric capacity and energy density of the cathode material. Here we demonstrate how to increase the gravimetric energy density of electrical energy storage devices based on the use of organic materials through exploitation of the strong ionic coupling between a reduced carbonyl functionality and small cations such as lithium (Li(+)) and magnesium (Mg(2+)). Binding of the cation to the reduced carbonyl results in a positive shift of the formal reduction potential of the carbonyl couple. This has the effect of increasing the cell voltage which, in turn, results in an increase in the energy density. We show how this interaction can be used to dramatically increase, by up to a factor of 2, the energy density for a selected case study using 1,2-di(thiophen-2-yl)ethane-1,2-dione (DTED). We have carried out electrochemical and computational studies in order to understand the thermodynamic (positive shift of 250 mV and 1 V in the formal potential for the first and second reductions, respectively, of the carbonyl groups of DTED) and kinetic effects between small radii cations (Li(+) and Mg(2+)) and the reduced carbonyl functionality of carbonyl-based organic molecules (C-bOMs).

  2. 蝎毒多肽对白血病细胞株KG1a干细胞活性的影响%Study on the effects of PESV on the viability of leukemia stem cells line KG1a

    杨向东; 李红玉; 李德冠; 史哲新; 杨文华; 颜田赅; 闫理想; 王兴丽



  3. Resistance of Leukemia KG1 a Cells with Positive N-cadherin in Phase G0Against Killing Activity of VP16%N-cadherin阳性白血病KG1a细胞系在G0期抵抗VP16杀伤的作用

    何侃; 于沛; 邢海燕; 李艳; 田征; 王敏; 唐克晶; 饶青


    抗药性是白血病干细胞的重要特征,为探索N-cadherin阳性的白血病细胞耐受化疗药物VP16杀伤作用的机制,本研究以白血病细胞系KGla为研究模型,利用流式细胞术测定N-cadherin阳性和N-cadherin阴性细胞在G0期比例的差异,利用G-CSF诱导KG1a细胞进入细胞周期,观察G0期细胞比例的变化,并测定诱导后KG1a细胞对VP16的敏感性;再利用EGTA抑制N-cadherin介导的细胞间黏附后,观察KG1a细胞耐药性的变化.结果 显示,N-cadherin阳性的KG1a细胞G0期比例高于N-cadherin阴性的细胞;诱导KG1a细胞进入细胞周期后G0期细胞比例明显下降,KG1a细胞对VP16的敏感性显著升高;利用EGTA处理KG1a细胞24小时抑制N-cadherin的作用后,KG1a细胞在G0期比例降低,KG1a细胞对VP16的药物敏感性显著升高.结论:N-cadherin通过介导白血病细胞之间的黏附作用,使白血病细胞处于G0期的静息状态,从而耐受VP16的杀伤作用.%This study was aimed to investigate the methylation status of WTI gene in leukemia cell lines and its relation with expression of WTI gene. The WTI gene was silenced by DNA methylation or histone deacetylation, and the expression of WTI gene was induced by using HDAC inhibitor and/or demethylation agent of DNA. Some leukemia cell lines (U937, HL-60, K562, KG1) were detected by RT-PCR, MS-PCR, restriction analysis, and DNA sequencing. U937 leukemic cells without WTI mRNA expression were incubated with HDAC inhibitor Trichostatin A (TSA) and/or demethylation agent decitabine. The results showed that the U937 cells did not express WTI gene, but HL-60, K562 and KG1 cells hyghly expressed WTI gene; WTI gene was unmethylated in HL-60 cells, but methylated in K562 and U937 cells. WTI expression could be reactivated by co-incubation with TSA and decitabine, but not was observed by using single drug. It is concluded that WTI promoter is methylated in some leukemia cells, however, the methylation can not affect

  4. Study on the Functional Expression of P2X7 Receptor in Human Leukemic Cell Line KG1a%人白血病细胞系KG1a中P2X7受体的表达和功能研究

    张秀军; 孟丽君



  5. Microwave irradiation decreases ATP, increases free [Mg2+], and alters in vivo intracellular reactions in rat brain

    Srivastava, Shireesh; Kashiwaya, Yoshihiro; Chen, Xuesong; Geiger, Jonathan D.; Pawlosky, Robert; Veech, Richard L.


    Rapid inactivation of metabolism is essential for accurately determining the concentrations of metabolic intermediates in the in vivo state. We compared a broad spectrum of energetic intermediate metabolites and neurotransmitters in brains obtained by microwave irradiation to those obtained by freeze blowing, the most rapid method of extracting and freezing rat brain. The concentrations of many intermediates, cytosolic free NAD(P)+/NAD(P)H ratios, as well as neurotransmitters were not affected by the microwave procedure. However, the brain concentrations of ATP were about 30% lower, whereas those of ADP, AMP, and GDP were higher in the microwave-irradiated compared with the freeze-blown brains. In addition, the hydrolysis of approximately 1 μmol/g of ATP, a major in vivo Mg2+-binding site, was related to approximately five-fold increase in free [Mg2+] (0.53 ± 0.07 mM in freeze blown vs. 2.91 mM ± 0.48 mM in microwaved brains), as determined from the ratio [citrate]/[isocitrate]. Consequently, many intracellular properties, such as the phosphorylation potential and the ΔG’ of ATP hydrolysis were significantly altered in microwaved tissue. The determinations of some glycolytic and TCA cycle metabolites, the phosphorylation potential, and the ΔG’ of ATP hydrolysis do not represent the in vivo state when using microwave-fixed brain tissue. PMID:23013291

  6. The Effect of Increasing Sn Content on High-Temperature Mechanical Deformation of an Mg-3%Cu-1%Ca Alloy

    Georgios S.E. Antipas


    Full Text Available Chill casting of magnesium alloy samples with secondary alloying elements of Cu, Ca and Sn at % w.t. concentrations in the range 1–5, 0.1–5 and 0.1–3 respectively, gave rise to appreciably enhanced resistance to high-temperature creep, while maintaining good heat conductivity. The latter was considered to be driven by Cu and Mg-Cu intermetallics while it was clear that Sn mediated the high-temperature performance, mainly via networks of Mg2Sn and MgCaSn precipitates along the Mg matrix grain boundaries. It was postulated that Sn formed intermetallics by preferential substitution of Ca atoms and, thus, did not degrade the heat conductivity by retaining Cu. The % w.t. stoichiometry with the optimum combination of heat conductivity and resistance to high-temperature creep was found to be Mg-3Cu-1Ca-0.1Sn.

  7. Nanoscale zero-valent iron (nZVI) synthesis in a Mg-aminoclay solution exhibits increased stability and reactivity for reductive decontamination

    Hwang, Yuhoon; Lee, Young-Chul; Mines, Paul D.


    .g. for chlorinated solvents hotspots. In this study, water-solubilized magnesium-aminoclay (MgAC) was applied for the first time as a stabilizing agent in the synthesis of nZVI. With increased doses of Mg-aminoclay applied in the synthesis mixture, nZVI particle growth was inhibited and thin sheathed grape-like n...


    Michel Santos PALHETA


    Full Text Available Context The rectal distension in dogs increases the rate of transitory lower esophageal sphincter relaxation considered the main factor causing gastroesophageal reflux. Objectives The aim of this study was evaluate the participation of the nitrergic pathway in the increased transitory lower esophageal sphincter relaxation rate induced by rectal distension in anesthetized dogs. Methods Male mongrel dogs (n = 21, weighing 10-15 kg, were fasted for 12 hours, with water ad libitum. Thereafter, they were anesthetized (ketamine 10 mg.Kg-1 + xylazine 20 mg.Kg-1, so as to carry out the esophageal motility evaluation protocol during 120 min. After a 30-minute basal period, the animals were randomly intravenous treated whith: saline solution 0.15M (1ml.Kg-1, L-NAME (3 mg.Kg-1, L-NAME (3 mg.Kg-1 + L-Arginine (200 mg.Kg-1, glibenclamide (1 mg.Kg-1 or methylene blue (3 mg.Kg-1. Forty-five min after these pre-treatments, the rectum was distended (rectal distension, 5 mL.Kg-1 or not (control with a latex balloon, with changes in the esophageal motility recorded over 45 min. Data were analyzed using ANOVA followed by Student Newman-Keuls test. Results In comparison to the respective control group, rectal distension induces an increase in transitory lower esophageal sphincter relaxation. Pre-treatment with L-NAME or methylene blue prevents (P<0.05 this phenomenon, which is reversible by L-Arginine plus L-NAME. However, pretreating with glibenclamide failed to abolish this process. Conclusions Therefore, these experiments suggested, that rectal distension increases transitory lower esophageal sphincter relaxation in dogs via through nitrergic pathways.

  9. Dietary Supplementation of Magnesium Oxide (MgO) Nanoparticles for Better Survival and Growth of the Freshwater Prawn Macrobrachium rosenbergii Post-larvae.

    Srinivasan, Veeran; Bhavan, Periyakali Saravana; Rajkumar, Gopalan; Satgurunathan, Thangavelu; Muralisankar, Thirunavukkarasu


    This study was performed to assess the growth-promoting potential of dietary magnesium oxide nanoparticles (MgO NPs) in Macrobrachium rosenbergii post-larvae (PL). MgO NPs were supplemented at 0, 100, 200, 300, 400 and 500 mg kg(-1) with the basal diet (containing 0.95 g Mg kg(-1)); the concentrations of Mg in MgO NP-supplemented diets were increased correspondingly (1.07, 1.15, 1.24, 1.37 and 1.46 g Mg kg(-1) respectively). MgO NP-supplemented diets were fed to M. rosenbergii PL (initial weight 0.11 ± 0.04 g) for a period of 90 days. In the carcasses of experimental prawns, the content of Mg was found to be elevated significantly with respect to the individual diet (102.14, 183.29, 205.46, 221.03, 237.10 and 254.36 μg Mg g(-1) respectively) when compared with that of the control. The contents of Cu, Zn, Fe, Ca, Na and K levels were also found to be elevated in the carcasses of experimental prawns. Significant (P MgO NP-supplemented-feed-fed PL. There were no significant elevations recorded in activities of antioxidant enzymes [superoxide dismutase (SOD) and catalase (CAT)], lipid peroxidation (LPO) and metabolic enzymes [glutamic oxaloacetic transaminase (GOT) and glutamic pyruvic transaminase (GPT)] recorded in any of the MgO NP-supplemented-feed-fed PL when compared with the control. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) showed increases in the staining intensity of polypeptide bands resolved in 500 mg kg(-1) MgO NP-supplemented-feed-fed PL when compared with the control. Based on the gradual improvement in attaining survival, growth, FCR, biochemical constituents and haemocyte population, this study recommends MgO NP supplementation of 500 mg kg(-1) for sustainable maintenance of M. rosenbergii PL. As the studied highest concentration of MgO NPs showed the best performance, it is necessary to study with beyond 500 mg kg(-1) of MgO NPs to optimize the actual concentration.

  10. Ultrafiltration of skimmed goat milk increases its nutritional value by concentrating nonfat solids such as proteins, Ca, P, Mg, and Zn.

    Moreno-Montoro, Miriam; Olalla, Manuel; Giménez-Martínez, Rafael; Bergillos-Meca, Triana; Ruiz-López, María Dolores; Cabrera-Vique, Carmen; Artacho, Reyes; Navarro-Alarcón, Miguel


    Goat milk has been reported to possess good nutritional and health-promoting properties. Usually, it must be concentrated before fermented products can be obtained. The aim of this study was to compare physicochemical and nutritional variables among raw (RM), skimmed (SM), and ultrafiltration-concentrated skimmed (UFM) goat milk. The density, acidity, ash, protein, casein, whey protein, Ca, P, Mg, and Zn values were significantly higher in UFM than in RM or SM. Dry extract and fat levels were significantly higher in UFM than in SM, and Mg content was significantly higher in UFM than in RM. Ultrafiltration also increased the solubility of Ca and Mg, changing their distribution in the milk. The higher concentrations of minerals and proteins, especially caseins, increase the nutritional value of UFM, which may therefore be more appropriate for goat milk yogurt manufacturing in comparison to RM or SM.

  11. Atlantic salmon (Salmo salar) require increased dietary levels of B-vitamins when fed diets with high inclusion of plant based ingredients.

    Hemre, Gro-Ingunn; Lock, Erik-Jan; Olsvik, Pål Asgeir; Hamre, Kristin; Espe, Marit; Torstensen, Bente Elisabeth; Silva, Joana; Hansen, Ann-Cecilie; Waagbø, Rune; Johansen, Johan S; Sanden, Monica; Sissener, Nini H


    Aiming to re-evaluate current recommendations for nutrient supplementations when Atlantic salmon are fed diets based on plant ingredients, two regression experiments, with parr and post-smolt, were conducted. A control diet was included to evaluate if ingredients supplied sufficient nutrients without any added nutrient package (NP). The nutrient package consisted of vitamins B, C, E, minerals, cholesterol, methionine, taurine and histidine. This paper focus on B-vitamins. In parr, growth, health and welfare parameters responded on NP additions, but this was not observed in the seawater stage. During three months of feeding, parr tripled their weight. Parr given diets added the NP above NRC (2011) showed improved protein retention, and reduced liver and viscera indices. Post-smolt fed the same diets during five months showed a doubling of weight, but did not respond to the variation in NP to the same extent as parr. Significant regressions were obtained in body compartments for several of the B-vitamins in the premix. Whole body biotin concentration was unaffected by micronutrient premix level, and mRNA expression of the enzymes dependent of biotin showed only weak increases with increased biotin. Muscle thiamine plateaued at a diet level similar to NRC (2011) recommendation in freshwater, and showed stable values independent on premix addition in seawater. The mRNA expression of the enzyme G6PDH (glucose-6-phosphate dehydrogenase) is sensitive to thiamine availability; results did not indicate any need to add thiamine above levels recommended for fish in general. Niacin showed a steady increase in whole body concentrations as feed niacin increased. Muscle riboflavin peaked at a diet level of 12.4 mg kg(-1). Sufficient riboflavin is important to avoid e.g., development of cataract. Cataract was not registered to be any problem, neither in fresh- nor in seawater. Cobalamin (B 12) in muscle and liver was saturated at 0.17 mg kg(-1) diet. Muscle pyridoxine showed a

  12. Desflurane increases heart rate independent of sympathetic activity in dogs.

    Picker, O; Schwarte, L A; Schindler, A W; Scheeren, T W L


    Desflurane has been shown to increase sympathetic activity and heart rate (HR) in a concentration-dependent manner. Nevertheless, desflurane, like all other volatile anaesthetics, increased HR in parallel to vagal inhibition in a previous study. Therefore, our hypothesis is that desflurane elicits tachycardia by vagal inhibition rather than by activation of the sympathetic nervous system. Six dogs were studied awake and during desflurane anaesthesia (1 and 2 MAC) alone, after pretreatment with propranolol (2 mg kg(-1) followed by 1 mg kg(-1) h(-1)), or after pre-treatment with atropine (0.1 mg kg(-1) followed by 0.05 mg kg(-1) h(-1)). The effects on HR and HR variability were compared by an analysis of variance (P MAC of desflurane from about 60 (awake) to 118 +/- 2 beats min(-1) (mean +/- SEM) in controls and to 106 +/- 3 beats min(-1) in dogs pre-treated with propranolol. In contrast, pretreatment with atropine increased HR from 64 +/- 2 to 147 +/- 5 beats min(-1) (awake) and HR decreased to 120 +/- 5 beats min(-1) after adding desflurane. High-frequency power correlated inversely with HR (r2 = 0.95/0.93) during desflurane alone and in the presence of beta-adrenoceptor blockade, with no significant difference between regression lines. There was no correlation between these variables during atropine/desflurane. The increase in HR elicited by desflurane mainly results from vagal inhibition and not from sympathetic activation.

  13. Serum from patients with ankylosing spondylitis can increase PPARD, fra-1, MMP7, OPG and RANKL expression in MG63 cells.

    Hu, Zaiying; Lin, Dongfang; Qi, Jun; Qiu, Minli; Lv, Qing; Li, Qiuxia; Lin, Zhiming; Liao, Zetao; Pan, Yunfeng; Jin, Ou; Wu, Yuqiong; Gu, Jieruo


    To explore the effects of serum from patients with ankylosing spondylitis on the canonical Wnt/β-catenin pathway and to assess whether the serum has an osteogenic effect in MG63 cells. MG63 cells were cultured with serum from 45 ankylosing spondylitis patients, 30 healthy controls, or 45 rheumatoid arthritis patients. The relative PPARD, fra-1, MMP7, OPG and RANKL mRNA levels were measured using quantitative real-time polymerase chain reaction. Associations between gene expression and patient demographics and clinical assessments were then analyzed. MG63 cells treated with serum from ankylosing spondylitis patients had higher PPARD, fra-1, MMP7 and OPG gene expression than did cells treated with serum from controls or rheumatoid arthritis patients (all pankylosing spondylitis or rheumatoid arthritis than in those treated with serum from controls (both pankylosing spondylitis patients than in those treated with serum from controls (p0.05). Serum from ankylosing spondylitis patients increases PPARD, fra-1, MMP7, OPG and RANKL expression and the OPG/RANKL ratio in MG63 cells; these effects may be due to the stimulatory effect of the serum on the Wnt pathway.

  14. Increased frequency and severity of developmental deformities in rough-skinned newt (Taricha granulosa) embryos exposed to road deicing salts (NaCl & MgCl2).

    Hopkins, Gareth R; French, Susannah S; Brodie, Edmund D


    Road-side aquatic ecosystems in North America are annually polluted with millions of tons of road deicing salts, which threaten the survival of amphibians which live and breed in these habitats. While much is known of the effects of NaCl, little is known of the second most-commonly used deicer, MgCl(2), which is now used exclusively in parts of the continent. Here we report that environmentally relevant concentrations of both NaCl and MgCl(2) cause increased incidence of developmental deformities in rough-skinned newt hatchlings that developed embryonically in these salts. In addition, we provide some of the first quantification of severity of different deformities, and reveal that increased salt concentrations increase both deformity frequency and severity. Our work contributes to the growing body of literature that suggests salamanders and newts are particularly vulnerable to salt, and that the emerging pollutant, MgCl(2) is comparable in its effects to the more traditionally-used NaCl.

  15. High-Temperature CO2 Sorption on Hydrotalcite Having a High Mg/Al Molar Ratio.

    Kim, Suji; Jeon, Sang Goo; Lee, Ki Bong


    Hydrotalcites having a Mg/Al molar ratio between 3 and 30 have been synthesized as promising high-temperature CO2 sorbents. The existence of NaNO3 in the hydrotalcite structure, which originates from excess magnesium nitrate in the precursor, markedly increases CO2 sorption uptake by hydrotalcite up to the record high value of 9.27 mol kg(-1) at 240 °C and 1 atm CO2.

  16. Increased oxidative stress and decreased activities of Ca2+/Mg2+-ATPase and Na+/K+-ATPase in the red blood cells of the hibernating black bear

    Chauhan, V.P.S.; Tsiouris, J.A.; Chauhan, A.; Sheikh, A.M.; Brown, W. Ted; Vaughan, M.


    During hibernation, animals undergo metabolic changes that result in reduced utilization of glucose and oxygen. Fat is known to be the preferential source of energy for hibernating animals. Malonyldialdehyde (MDA) is an end product of fatty acid oxidation, and is generally used as an index of lipid peroxidation. We report here that peroxidation of lipids is increased in the plasma and in the membranes of red blood cells in black bears during hibernation. The plasma MDA content was about four fold higher during hibernation as compared to that during the active, non-hibernating state (P increased during hibernation (P increased oxidative stress, and have reduced activities of membrane-bound enzymes such as Ca2+/Mg2+-ATPase and Na+/K+-ATPase. These changes can be considered part of the adaptive for survival process of metabolic depression. ?? 2002 Elsevier Science Inc. All rights reserved.

  17. Noradrenaline increases intracellular glutathione in human astrocytoma U-251 MG cells by inducing glutamate-cysteine ligase protein via β3-adrenoceptor stimulation.

    Yoshioka, Yasuhiro; Kadoi, Hisatsugu; Yamamuro, Akiko; Ishimaru, Yuki; Maeda, Sadaaki


    Glutathione (GSH) plays a critical role in protecting cells from oxidative damage. Since neurons rely on the supply of GSH from astrocytes to maintain optimal intracellular GSH concentrations, the GSH concentration of astrocytes is important for the survival of neighboring neurons against oxidative stress. The neurotransmitter noradrenaline is known to modulate the functions of astrocytes and has been suggested to have neuroprotective properties in neurodegenerative diseases. To elucidate the mechanisms underlying the neuroprotective properties of noradrenaline, in this study, we investigated the effect of noradrenaline on the concentrations of intracellular GSH in human U-251 malignant glioma (MG; astrocytoma) cells. Treatment of the cells with noradrenaline for 24h concentration-dependently increased their intracellular GSH concentration. This increase was inhibited by a non-selective β-adrenoceptor antagonist propranolol and by a selective β3-adrenoceptor antagonist SR59230A, but not by a non-selective α-adrenoceptor antagonist phenoxybenzamine, or by a selective β1-adrenoceptor antagonist atenolol or by a selective β2-adrenoceptor antagonist butoxamine. In addition, the selective β3-adrenoceptor agonist CL316243 increased the intracellular GSH in U-251 MG cells. Treatment of the cells with noradrenaline (10μM) for 24h increased the protein level of the catalytic subunit of glutamate-cysteine ligase (GCLc), the rate-limiting enzyme of GSH synthesis; and this increase was inhibited by SR59230A. These results thus suggest that noradrenaline increased the GSH concentration in astrocytes by inducing GCLc protein in them via β3-adrenoceptor stimulation.

  18. Acute intraperitoneal injection of caffeine improves endurance exercise performance in association with increasing brain dopamine release during exercise.

    Zheng, Xinyan; Takatsu, Satomi; Wang, Hongli; Hasegawa, Hiroshi


    The purpose of this study was to examine changes of thermoregulation, neurotransmitters in the preoptic area and anterior hypothalamus (PO/AH), which is the thermoregulatory center, and endurance exercise performance after the intraperitoneal injection of caffeine in rats. Core body temperature (Tcore), oxygen consumption (VO₂) and tail skin temperature (Ttail) were measured. A microdialysis probe was inserted in the PO/AH, and samples for the measurements of extracellular dopamine (DA), noradrenaline (NA) and serotonin (5-HT) levels were collected. During the rest experiment, 1 h after baseline collections in the chamber (23 °C), the rats were intraperitoneally injected with saline, or 3 mg kg(-1) or 10 mg kg(-1) caffeine. The duration of the test was 4 h. During the exercise experiment, baseline collections on the treadmill were obtained for 1 h. One hour before the start of exercise, rats were intraperitoneally injected with either 10 mg kg(-1) caffeine (CAF) or saline (SAL). Animals ran until fatigue at a speed of 18 m min(-1), at a 5% grade, on the treadmill in a normal environment (23 °C). At rest, 3 mg kg(-1) caffeine did not influence Tcore, Ttail, VO₂, extracellular DA, NA and 5-HT. 10 mg kg(-1) caffeine caused significant increases in Tcore, VO₂, Ttail and extracellular DA in the PO/AH. In addition, 10 mg kg(-1) caffeine increased the run time to fatigue (SAL: 104.4 ± 30.9 min, CAF: 134.0 ± 31.1 min, pexercise increased Tcore, VO₂, Ttail and extracellular DA in the PO/AH. NA increased during exercise, while neither caffeine nor exercise changed 5-HT. These results indicate that caffeine has ergogenic and hyperthermic effects, and these effects may be related to changes of DA release in the brain.

  19. [Intensive blood pressure reduction in patients with increased cardiovascular risk with high-dose combination therapy of 160 mg valsartan plus 25 mg hydrochlorothiazide. Results of the MACHT II observational study].

    Schühlen, Helmut; Abts, Markus; Kastrati, Dorejd


    Hypertension is one of the most common cardiovascular risk factors. Thus, achievement and maintenance of a sufficient reduction of blood pressure markedly contribute to successful risk prevention. Therefore, the primary objective of this observational postmarketing study MACHT II was to examine the efficacy and the tolerability of the combined therapy with 160 mg valsartan plus 25 mg hydrochlorothiazide (HCT) in a large population of patients with a well-defined individual risk profile and treatment status at baseline. This multicenter, open singlearm trial involved 17,591 patients, either without or with insufficient prior antihypertensive medication. The mean absolute blood pressure improvement obtained for the total population was -26.8 mmHg systolic and -13.5 mmHg diastolic. The maximum absolute improvement in blood pressure was observed in patients with severe hypertension: on average, the systolic blood pressure decreased by 41.7 mmHg and the diastolic blood pressure by 20.5 mmHg compared to baseline. The results demonstrated an effective blood pressure reduction in every subgroup analyzed: mean values of systolic and diastolic blood pressure decreased to high normal values. More than two thirds of the patients achieved normalization of the diastolic blood pressure. Normalization of diastolic blood pressure was observed in 65.2% of the patients with previous antihypertensive medication and in 74.3% of those without previous antihypertensive medication. The overall incidence of adverse drug reactions was 0.6%. The combined antihypertensive therapy with 160 mg valsartan plus 25 mg HCT shows a high degree of efficacy and a very favorable safety profile.

  20. Increasing women's choices in medical abortion: a study of misoprostol 400 microg swallowed immediately or held sublingually following 200 mg mifepristone.

    Akin, Ayşe; Dabash, Rasha; Dilbaz, Berna; Aktün, Hale; Dursun, Polat; Kiran, Sibel; Aksan, Güldeniz; Doğan, Bahar; Winikoff, Beverly


    To assess the efficacy and acceptability of two misoprostol regimens (400 microg oral or sublingual) following mifepristone for medical abortion. Women seeking abortion with gestations of 56 days or less since onset of their last menstrual period were offered medical abortion as an alternative to a surgical procedure. A total of 207 eligible and consenting women were given mifepristone (200 mg oral) and the option of taking 400 microg misoprostol either orally or sublingually two days later, with the option of home-use. Two weeks later, treatment success, satisfaction, and the frequency and acceptability of side effects were assessed. Most women (97.6%) opted for home use of misoprostol and almost three quarters selected the oral route. Overall efficacy, acceptability of side effects and satisfaction were high in both groups. The success rate was lower after sublingual than after oral administration but not significantly so (91.3% vs. 96.3%, p = 0.23, RR: 0.93, 95% CI = 0.85-1.02). The frequency and average duration of side effects in both groups were comparable except for pain/cramps and fever/chills, which were more frequently associated with the sublingual route. This study re-emphasises the feasibility of integrating medical abortion into health services in Turkey and the potential to increase choices for women.

  1. Increase in IL-6 levels among major depressive disorder patients after a 6-week treatment with duloxetine 60 mg/day: a preliminary observation

    Michele Fornaro


    Full Text Available Michele Fornaro1, Matteo Martino1, Florinda Battaglia2, Salvatore Colicchio3, Giulio Perugi41Department of Neuroscience, Section of Psychiatry, University of Genova, Genoa, Italy; 2Center of Excellence for Biomedical Research (CEBR, Genoa, Italy; 3Department of Neurosciences, Catholic University, Rome, Italy; 4Department of Psychiatry, Institute of Behavioral Sciences, University of Pisa, Pisa, ItalyBackground: Immune modifications, including changes in interleukin (IL-6 levels, have often been observed in major depressive disorder (MDD during treatment with selective serotonin reuptake inhibitors (SSRIs or the serotonin norepinephrine reuptake inhibitor (SNRI venlafaxine. Nevertheless, no equivalent observation for the SNRI duloxetine has been made to date.Method: Sixteen patients diagnosed with MDD and an actual major depressive episode according to DSM-IV criteria and 16 healthy controls entered a 6-week trial with duloxetine 60 mg/day. All subjects (n = 32 were assessed using the Hamilton Depression Rating Scale (HAM-D, the Young Mania Rating Scale (YMRS, and were monitored for IL-6 levels both at baseline and at week 6. Blood samples for IL-6 levels were evaluated by ELISA.Results: After 6 weeks of treatment, the mean total scores for HAM-D declined both in the depressed and control groups, while IL-6 modification showed an opposite trend both in depressed (12.38 ± 19.80 to 19.73 ± 18.94 pg/mL and control subjects (12.25 ± 21.12 to 17.63 ± 20.44 pg/mL, as did YMRS (ns, although none of the subjects switched to (hypomania. Of note, IL-6 levels increased significantly only in the responders subgroup (n = 9; P = 0.012.Conclusion: The small sample size and weak design of this study limit the validity of our results, which should be regarded as preliminary only. Nonetheless, the trend of increasing IL-6 levels observed in responder patients treated with duloxetine should prompt further controlled, extended studies with larger samples, with

  2. Sargassum polycystum reduces hyperglycaemia, dyslipidaemia and oxidative stress via increasing insulin sensitivity in a rat model of type 2 diabetes.

    Motshakeri, Mahsa; Ebrahimi, Mahdi; Goh, Yong Meng; Matanjun, Patricia; Mohamed, Suhaila


    Sargassum polycystum, a brown seaweed, contains various nutrients and bioactive compounds that have antioxidant and healing properties. The research hypothesises that antioxidants and pigments in dietary S. polycystum extracts can improve insulin sensitivity, blood sugar levels and blood lipid levels in a rat model of type 2 diabetes. The diabetes was induced by a high-sugar, high-fat diet for 16 weeks to enhance insulin resistance, followed by a low-dose intraperitoneal injection of streptozotocin (35 mg kg(-1) body weight). The doses of S. polycystum tested on diabetic rats were 150 and 300 mg kg(-1) body weight for the ethanolic extract or 150 and 300 mg kg(-1) for the water extract. Normal rats, untreated diabetic and metformin-treated diabetic rats (n = 6) were used as control. Both doses of the alcohol extract of S. polycystum and the 300 mg kg(-1) water extract, significantly reduced blood glucose and glycosylated haemoglobin (HbA1C ) levels. Serum total cholesterol, triglyceride levels and plasma atherogenic index were significantly decreased after 22 days treatment in all seaweed groups. Unlike metformin, S. polycystum did not significantly change plasma insulin in the rats, but increased the response to insulin. The consumption of either ethanolic or water extracts of S. polycystum dose dependently reduced dyslipidaemia in type 2 diabetic rats. S. polycystum is a potential insulin sensitiser, for a comestible complementary therapy in the management of type 2 diabetes which can help reduce atherogenic risk. © 2012 Society of Chemical Industry.

  3. Temperature increase due to Joule heating in a nanostructured MgO-based magnetic tunnel junction over a wide current-pulse range.

    Jeong, Boram; Lim, Sang Ho


    The temperature increase due to Joule heating in a nanopillar of a magnetic tunnel junction sandwiched by top and bottom electrodes was calculated by the finite element method. The results for the critical condition for the current-induced magnetization switching measured over a wide current-pulse range were taken from the literature. At long pulse widths, the temperature increase was solely dependent on the magnitude of the critical current density. However, no saturation in the temperature increase occurred for short pulse widths. In this case, the temperature increase additionally depended on the pulse width, so that a broad maximum occurred in the pulse width (or the critical current density) dependence of the temperature increase. The original results for the critical condition were corrected by accounting for the temperature increase and these corrected results, together with the Slonczewski equation, were used to extract an accurate value for the thermal stability factor.

  4. Dexamethasone Treatment Reverses Cognitive Impairment but Increases Brain Oxidative Stress in Rats Submitted to Pneumococcal Meningitis

    Tatiana Barichello


    Full Text Available Pneumococcal meningitis is associated with a significant mortality rate and neurologic sequelae. The animals received either 10 μL of saline or a S. pneumoniae suspension and were randomized into different groups: sham: placebo with dexamethasone 0.7 mg/kg/1 day; placebo with dexamethasone 0.2 mg/kg/7 days; meningitis groups: dexamethasone 0.7 mg/kg/1 day and dexamethasone 0.2 mg/kg/7 days. Ten days after induction we evaluated memory and oxidative stress parameters in hippocampus and cortex. In the step-down inhibitory avoidance task, we observed memory impairment in the meningitis group with dexamethasone 0.2 mg/kg/7 days. The lipid peroxidation was increased in hippocampus in the meningitis groups with dexamethasone and in cortex only in the meningitis group with dexamethasone 0.2 mg/kg/7 days. The protein carbonyl was increased in hippocampus in the meningitis groups with dexamethasone and in cortex in the meningitis groups with and without dexamethasone. There was a decrease in the proteins integrity in hippocampus in all groups receiving treatment with dexamethasone and in cortex in all groups with dexamethasone (0.7 mg/kg/1 day. The mitochondrial superoxide was increased in the hippocampus and cortex in the meningitis group with dexamethasone 0.2 mg/kg/7 days. Our findings demonstrate that dexamethasone reverted cognitive impairment but increased brain oxidative stress in hippocampus and cortex in Wistar rats ten days after pneumococcal meningitis induction.

  5. Lipid peroxidation in the kidney of rats treated with V and/or Mg in drinking water.

    Scibior, Agnieszka; Zaporowska, Halina; Niedźwiecka, Irmina


    LPO induced by in vitro treatment of kidney supernatants with exogenous Fe or V or Mg (600, 800 and 1000 microm) were a consequence of independent action of those metals and they also resulted from the interactions between exogenous Fe (Fe(exog)) and endogenous V (V(end)) and between V(end) and exogenous V (V(exog)). In conclusion, V (as NaVO(3)) consumed by the rats with drinking water at a dose of 12.9 mg V kg(-1) b.w. per 24 h for 12 weeks increased the basal LPO and markedly enhanced TAS in the renal tissue. Its pro-oxidant potential was also found in in vitro conditions. The Mg dose (6 mg Mg kg(-1) b.w. per 24 h) ingested by the rats together with V (12.7 mg V kg(-1) b.w. per 24 h) neither reduced nor intensified the spontaneous LPO, compared with V-only intoxicated animals; however, the stimulating effect of Mg on LPO was revealed in in vitro conditions.

  6. Hydrocarbon contamination increases the liquid water content of frozen Antarctic soils.

    Siciliano, Steven D; Schafer, Alexis N; Forgeron, Michelle A M; Snape, Ian


    We do not yet understand why fuel spills can cause greater damage in polar soils than in temperate soils. The role of water in the freezing environment may partly be responsible for why polar soils are more sensitive to pollution. We hypothesized that hydrocarbons alter the liquid water in frozen soil, and we evaluated this hypothesis by conducting laboratory and field experiments at Casey Station, Antarctica. Liquid water content in frozen soils (theta(liquid)) was estimated by time domain reflectometry in laboratory, field collected soils, and in situ field measurements. Our results demonstrate an increase in liquid water associated with hydrocarbon contamination in frozen soils. The dependence of theta(liquid) on aged fuel and spiked fuel were almost identical,with a slope of 2.6 x 10(-6) mg TPH (total petroleum hydrocarbons) kg(-1) for aged fuel and 3.1 x 10(-6) mg TPH kg(-1) for spiked fuel. In situ measurements found theta(liquid) depends, r2 = 0.75, on fuel for silt loam soils (theta(liquid) = 0.094 + 7.8 x 10(-6) mg TPH kg(-1)) but not on fuel for silt clay loam soils. In our study, theta(liquid) doubled in field soils and quadrupled in laboratory soils contaminated with diesel which may have profound implications on frost heave models in contaminated soils.

  7. Conversion of Natural Ecosystems to Cropland Increases the Soil Net Nitrogen mineralization and Nitrification in Tibet

    YANG Li-Lin; ZHANG Fu-Suo; MAO Ren-Zhao; JU Xiao-Tang; Cai Xiao-Bu; LI Ya-Hai


    A comparative study was conducted to determine the NH+4 and NO-3 concentrations in soil profiles and to examine the net itrogen (N) mineralization and nitrification in adjacent forest, grassland, and cropland soils on the Tibetan Plateau. Cropland soil showed significantly higher inorganic N concentrations in soil profiles compared with forest and grassland soils. NO-3-Naccounted for 70%-90% of inorganic N in cropland soil, while NH+4-N was the main form of inorganic N in forest and grassland soils. The average net N mineralization rate at 0-20 cm depth was approximately twice in cropland soil (1.48 mg kg-1 d-1) as high as in forest (0.83 mg kg-1 d-1) or grassland soil (0.72 mg kg-1 d-1). Cropland showed strong net nitrification, with the net rate almost equal to the total net N mineralization. Urea addition stimulated soil respiration, particularly in forest oil. Most urea-N, however, remained as NH+4 in forest and grassland soils, while NO-3 was the main form of inorganic N to increase n cropland soil. Higher rates of net nitrification in cropland soils suggest that land use change on the Tibetan Plateau may lead to high N losses through nitrate leaching.

  8. Exposure to inorganic arsenic in soil increases urinary inorganic arsenic concentrations of residents living in old mining areas.

    Hinwood, Andrea L; Sim, Malcolm R; Jolley, Damien; de Klerk, Nick; Bastone, Elisa B; Gerostamoulos, Jim; Drummer, Olaf H


    The short term human exposure studies conducted on populations exposed to high concentrations of inorganic arsenic in soil have been inconsistent in demonstrating a relationship between environmental concentrations and exposure measures. In Australia there are many areas with very high arsenic concentrations in residential soil most typically associated with gold mining activities in rural areas. This study aimed to investigate the relationship between environmental arsenic and urinary inorganic arsenic concentrations in a population living in a gold mining area (soil arsenic concentrations between 9 and 9900 mg kg(-1)), and a control population with low arsenic levels in soil (between 1 and 80 mg kg(-1)). Risk factors for increased urinary arsenic concentrations were also explored. There was a weak but significant relationship between soil arsenic concentrations and inorganic urinary arsenic concentration with a Spearman correlation coefficient of 0.39. When participants with greater than 100 mg kg(-1) arsenic in residential soil were selected, the coefficient increased to 0.64. The geometric mean urinary inorganic arsenic concentration for the exposed group was 1.64 microg L(-1) (risk factors. These results show that high concentrations of arsenic in soil can make a contribution to urinary inorganic arsenic concentrations.

  9. Increasing arsenic sorption on red mud by phosphogypsum addition.

    Lopes, G; Guilherme, L R G; Costa, E T S; Curi, N; Penha, H G V


    Mining by-products have been tested as adsorbents for arsenic in order to reduce As bioavailability. This study evaluated a red mud (RM) treated with or without phosphogypsum (G) in order to improve its As retention. Red mud and G samples and their mixtures were chemically and mineralogically characterized to gather information concerning their composition, which is key for a better understanding of the adsorbent properties. Phosphogypsum was added to RM in the following proportions: 0, 1, 2, 5, 10, and 25% by weight. These mixtures were subjected to As adsorption and desorption and tested for their maximum adsorption capacity of As (AsMAC). Arsenic adsorption increased upon increasing the proportion of G added to RM. The AsMAC at pure RM reached 909 mg kg(-1), whereas the 75%-RM+25%-G mixture sorbed up to 3333 mg kg(-1) of As, i.e., a 3.5-fold increase in AsMAC. Using G in mixtures with RM increases the efficiency of As adsorption due to the presence of Ca(2+), which alters the charge balance of the adsorbent, leading to the formation of ternary complexes. Addition of G to RM is thus a promising technique to improve As retention, while providing additional value to both by-products, G and RM.

  10. Análise de crescimento em Heteranthera reniformis, sob diferentes teores de Ca, Mg e S Growth analysis in Heteranthera reniformis under different contents of Ca, Mg and S

    Vanessa David Domingos


    S, plus the control (100% of the solution base, with 4 replicates in the period of 35 days in greenhouse. The increase of contents of Ca produced significant reduction in the leaf. The largest areas leaf occurred in solutions of 25% of Ca and 50% of Mg and S. The largest proportion of dry biomass was found in the stem, except with 25% of Ca (40 mg.L-1 in solution that produced larger leaf area and larger specific leaf area. Among different Mg contents, larger biomasses were observed at 50% of Mg (19, 2 mg.L-1 and, for S, there were not significant differences, except at 0% of S in solution. The solution with 160 mg.L-1 of Ca produced the largest concentration of Ca in leaf (56, 6 The contents of Ca, Mg and S in solution corresponded to a proportional increase in the plant. The contents of sulfur in leaves and in stems increased with the concentration of S, whereas the content in roots reduced in the concentrations between 12,8 and 38,4 mg.L-1.

  11. Food intake inhibition in rainbow trout induced by activation of serotonin 5-HT2C receptors is associated with increases in POMC, CART and CRF mRNA abundance in hypothalamus.

    Pérez-Maceira, Jorge J; Otero-Rodiño, Cristina; Mancebo, María J; Soengas, José L; Aldegunde, Manuel


    In rainbow trout, the food intake inhibition induced by serotonin occurs through 5-HT2C and 5-HT1A receptors, though the mechanisms involved are still unknown. Therefore, we assessed if a direct stimulation of 5-HT2C and 5-HT1A serotonin receptors (resulting in decreased food intake in rainbow trout), affects gene expression of neuropeptides involved in the control of food intake, such as pro-opiomelanocortin (POMC), cocaine- and amphetamine-regulated transcript (CART), corticotrophin releasing factor (CRF), and agouti-related peptide (AgRP). In a first set of experiments, the injection of the 5-HT2C receptor agonists MK212 (60 μg kg(-1) icv) and WAY 161503 (1 mg kg(-1) ip), and of the 5-HT1A receptor agonist 8-OH-DPAT (1 mg kg(-1) ip and 30 μg kg(-1) icv) induced food intake inhibition. In a second set of experiments, we observed that the injection of MK212 or WAY 161503 (1 and 3 mg kg(-1)) significantly increased hypothalamic POMC mRNA abundance. CART mRNA abundance in hypothalamus was enhanced by treatment with MK212 and unaffected by WAY 161503. The administration of the 5-HT1A receptor agonist 8-OH-DPAT did not induce any significant variation in the hypothalamic POMC or CART mRNA levels. CRF mRNA abundance was only affected by MK212 that increased hypothalamic values. Finally, hypothalamic AgRP mRNA abundance was only evaluated with the agonist 5-HT2C MK212 resulting in no significant effects. The results show that the reduction in food intake mediated by 5-HT2C receptors is associated with increases in hypothalamic POMC, CART and CRF mRNA abundance.

  12. Green manure addition to soil increases grain zinc concentration in bread wheat.

    Forough Aghili

    Full Text Available Zinc (Zn deficiency is a major problem for many people living on wheat-based diets. Here, we explored whether addition of green manure of red clover and sunflower to a calcareous soil or inoculating a non-indigenous arbuscular mycorrhizal fungal (AMF strain may increase grain Zn concentration in bread wheat. For this purpose we performed a multifactorial pot experiment, in which the effects of two green manures (red clover, sunflower, ZnSO4 application, soil γ-irradiation (elimination of naturally occurring AMF, and AMF inoculation were tested. Both green manures were labeled with 65Zn radiotracer to record the Zn recoveries in the aboveground plant biomass. Application of ZnSO4 fertilizer increased grain Zn concentration from 20 to 39 mg Zn kg-1 and sole addition of green manure of sunflower to soil raised grain Zn concentration to 31 mg Zn kg-1. Adding the two together to soil increased grain Zn concentration even further to 54 mg Zn kg-1. Mixing green manure of sunflower to soil mobilized additional 48 µg Zn (kg soil-1 for transfer to the aboveground plant biomass, compared to the total of 132 µg Zn (kg soil-1 taken up from plain soil when neither green manure nor ZnSO4 were applied. Green manure amendments to soil also raised the DTPA-extractable Zn in soil. Inoculating a non-indigenous AMF did not increase plant Zn uptake. The study thus showed that organic matter amendments to soil can contribute to a better utilization of naturally stocked soil micronutrients, and thereby reduce any need for major external inputs.

  13. Increase of the seizure threshold in C57BL/6 mice after citicoline administration.

    Karpova, M N; Zin'kovskii, K A; Kuznetsova, L V; Klishina, N V


    We studied the dose-dependent effect of preventive intraperitoneal injection of citicoline (cytidine 5'-diphosphocholine) on acute generalized epileptiform activity in C57Bl/6 mice. The duration of citicoline action was also evaluated. Administration of citicoline in doses of 500 and 1000 mg/kg 1 h before treatment with the convulsant agent pentylenetetrazole produced an anticonvulsant effect. This effect was manifested in an increase of the threshold of clonic seizures and tonic phase of seizures with lethal outcome. Moreover, the latency of seizure development was elevated under these conditions. The anticonvulsant effect of citicoline persisted for 6 h after its injection.

  14. Mycorrhizae increase arsenic uptake by the hyperaccumulator Chinese brake fern (Pteris vittata L.).

    Al Agely, Abid; Sylvia, David M; Ma, Lena Q


    Chinese brake fern (Pteris vittata L.) is a hyperaccumulator of arsenic (As) that grows naturally on soils in the southern United States. It is reasonable to expect that mycorrhizal symbiosis may be involved in As uptake by this fern. This is because arbuscular mycorrhizal (AM) fungi have a well-documented role in increasing plant phosphorus (P) uptake, P and As have similar chemical properties, and ferns are known to be colonized by AM fungi. We conducted a factorial greenhouse experiment with three levels of As (0, 50, and 100 mg kg(-1)) and P (0, 25, and 50 mg kg(-1)) and with and without Chinese brake fern colonized by a community of AM fungi from an As-contaminated site. We found that the AM fungi not only tolerated As amendment, but their presence increased frond dry mass at the highest As application rate. Furthermore, the AM fungi increased As uptake across a range of P levels, while P uptake was generally increased only when there was no As amendment. These data indicate that AM fungi have an important role in arsenic accumulation by Chinese brake fern. Therefore, to effectively phytoremediate As-contaminated soils, the mycorrhizal status of ferns needs to be taken into account.

  15. The oleic acid esterification of policosanol increases its bioavailability and hypocholesterolemic action in rats

    Hain, D.; Valenzuela, A.; Branes, M. C.; Fuenzalida, M.; Videla, L. A.


    Policosanol comprises a mixture of long-chain aliphatic alcohols from sugarcane wax. More than 50 studies indicate that policosanol decreases serum cholesterol, while others failed to reproduce this effect. The objective of this investigation was to assess the bioavailability of esterified policosanol and non-esterified policosanol (NEP), in relation to their hypocholesterolemic effects. Sprague Dawley rats were given a daily oral dose of 100 mg/kg of NEP, 117 mg kg1 of butyric acid esterified policosanol (BAEP), or 164 mg kg1 of oleic acid esterified policosanol (OAEP). Policosanol absorption was evaluated in plasma between 0 and 3 hours after ingestion. To assess changes in total cholesterol, LDL-cholesterol, HDLcholesterol and triacylglycerols in plasma and liver 3-hydroxy- 3-methylglutaryl coenzyme A reductase (HMG- CoA red) phosphorylation, the rats were supplemented with nonesterified or esterified policosanol for 5 weeks. The results indicate that policosanol absorption was significantly greater in OAEP-treated rats than in those subjected to NEP or BAEP administration. OAEP significantly reduced plasma total and LDL-cholesterol in rats, in addition to a 5.6-fold increase (P < 0.05) in the hepatic content of phosphorylated HMG-CoA red over the control values. In conclusion, esterification of policosanol with oleic acid enhances policosanol bioavailability, and significantly improves the serum lipid profile in normocholesterolemic rats in association with the inactivation of HMG-CoA red controlling cholesterogenesis. (Author) 49 refs.

  16. Direct observation of increasing CO

    van Heuven, S.M.A.C.; Hoppema, M.; Huhn, O.; Slagter, H.A.; de Baar, H.J.W.


    The World Ocean takes up a large portion of the anthropogenic CO2 emitted into the atmosphere. Determining the resulting increase in dissolved inorganic carbon (C-T, expressed in mu mol kg(-1)) is challenging, particularly in the sub-surface and deep Southern Ocean where the time rate of change of

  17. Direct observation of increasing CO

    van Heuven, S.M.A.C.; Hoppema, M.; Huhn, O.; Slagter, H.A.; de Baar, H.J.W.


    The World Ocean takes up a large portion of the anthropogenic CO2 emitted into the atmosphere. Determining the resulting increase in dissolved inorganic carbon (C-T, expressed in mu mol kg(-1)) is challenging, particularly in the sub-surface and deep Southern Ocean where the time rate of change of C

  18. Spirulina elicits the activation of innate immunity and increases resistance against Vibrio alginolyticus in shrimp.

    Chen, Yu-Yuan; Chen, Jiann-Chu; Tayag, Carina Miranda; Li, Hui-Fang; Putra, Dedi Fazriansyah; Kuo, Yi-Hsuan; Bai, Jia-Chin; Chang, Yu-Hsuan


    The effect of Spirulina dried powder (SDP) on the immune response of white shrimp Litopenaeus vannamei was studied in vitro and in vivo. Incubating shrimp haemocytes in 0.5 mg ml(-1) SDP caused the degranulation of haemocytes and a reduction in the percentage of large cells within 30 min. Shrimp haemocytes incubated in 1 mg ml(-1) SDP significantly increased their phenoloxidase (PO) activity, serine proteinase activity, and respiratory burst activity (RB, release of superoxide anion). A recombinant protein of lipopolysaccharide and β-1,3-glucan binding protein (LGBP) of the white shrimp was produced, named rLvLGBP, and examined for its binding with SDP. An ELISA binding assay showed that rLvLGBP binds to SDP with a dissociation constant of 0.0507 μM. In another experiment, shrimp fed diets containing SDP at 0 (control), 30, and 60 g kg(-1) after four weeks were examined for LGBP transcript level and lysozyme activity, as well as phagocytic activity, clearance efficiency, and resistance to Vibrio alginolyticus. These parameters were significantly higher in shrimp receiving diets containing SDP at 60 g kg(-1) or 30 g kg(-1) than in controls. In conclusion, shrimp haemocytes receiving SDP provoked the activation of innate immunity as evidenced by the recognition and binding of LGBP, degranulation of haemocytes, reduction in the percentage of large cells, increases in PO activity, serine proteinase activity, superoxide anion levels, and up-regulated LGBP transcript levels. Shrimp receiving diets containing SDP had increased lysozyme activity and resistance against V. alginolyticus infection. This study showed the mechanism underlying the immunostimulatory action of Spirulina and its immune response in shrimp.

  19. Demonstration of Mg2FeH6 as heat storage material at temperatures up to 550 °C

    Urbanczyk, R.; Meggouh, M.; Moury, R.; Peinecke, K.; Peil, S.; Felderhoff, M.


    The storage of heat at high temperatures, which can be used to generate electricity after sunset in concentrating solar power plants, is one of the most challenging technologies. The use of metal hydride could be one possibility to solve the problem. During the endothermic heat storage process, the metal hydride is decomposed releasing hydrogen, which then can be stored. During the exothermic reaction of the metal with the hydrogen gas, the stored heat is then released. Previous research had shown that Mg and Fe powders can be used at temperatures up to 550 °C for heat storage and shows excellent cycle stability over hundreds of cycles without any degradation. Here, we describe the results of testing of a tube storage tank that contained 211 g of Mg and Fe powders in 2:1 ratio. Twenty-three dehydrogenations (storage) and 23 hydrogenations (heat release) in the temperature range between of 395 and 515 °C and pressure range between 1.5 and 8.6 MPa were done. During the dehydrogenation, 0.41-0.42 kWhth kg-1 of heat based on material 2 Mg/Fe can be stored in the tank. After testing, mainly Mg2FeH6 was observed and small amounts of MgH2 and Fe metal can be detected in the hydride samples. This means that the heat storage capacity of the system could be further increased if only Mg2FeH6 is produced during subsequent cycles.

  20. Multi scale impacts of a (Mg,Ca)-Pb exchange on the permeability increase of a bentonite; Impacts ''multi echelle'' d'un echange (Mg,Ca)-Pb et ses consequences sur l'augmentation de la permeabilite d'une bentonite

    Jozja, N.; Baillif, P.; Touray, J.C.; Pons, Ch.H.; Muller, F.; Burgevin, C. [Institut des Sciences de la Terre d' Orleans, UMR 6313, 45 - Orleans (France)


    The article addresses the structural effects of solutions of lead nitrate on a suspended or compacted bentonite. A permeability increase is observed on compacted clay. Investigating the composition of output solution, using X-Rays Diffusion at Small Angles and Scanning Electron Microscopy, this permeability increase is explained from structural variations at nano-metric (reduction of particle size) and micrometric scales (micro-fissuration of aggregates). (authors)

  1. The role of MgO content in ex situ MgB2 wires

    Kovac, P.; Hugek, I.; Meligek, T.;


    An experimental study of the effect of MgO content in the MgB2 powder used for ex situ made composite wires was carried out. Two single-core MgB2/Fe/Cu wires were made using commercial MgB2 powders from Alfa Aesar containing different fraction of MgO. Critical temperature and critical currents...... of as-deformed and heat-treated wires were measured. The differences between the wires are discussed and correlated with the MgO content. It was found that by increasing the amount of MgO, the inter-grain connectivity worsens, but well distributed and low size MgO particles improve flux pinning....

  2. Effect of heavy metals on pH buffering capacity and solubility of Ca, Mg, K, and P in non-spiked and heavy metal-spiked soils.

    Najafi, Sarvenaz; Jalali, Mohsen


    In many parts of the world, soil acidification and heavy metal contamination has become a serious concern due to the adverse effects on chemical properties of soil and crop yield. The aim of this study was to investigate the effect of pH (in the range of 1 to 3 units above and below the native pH of soils) on calcium (Ca), magnesium (Mg), potassium (K), and phosphorus (P) solubility in non-spiked and heavy metal-spiked soil samples. Spiked samples were prepared by cadmium (Cd), copper (Cu), nickel (Ni), and zinc (Zn) as chloride salts and incubating soils for 40 days. The pH buffering capacity (pHBC) of each sample was determined by plotting the amount of H(+) or OH(-) added (mmol kg(-1)) versus the related pH value. The pHBC of soils ranged from 47.1 to 1302.5 mmol kg(-1) for non-spiked samples and from 45.0 to 1187.4 mmol kg(-1) for spiked soil samples. The pHBC values were higher in soil 2 (non-spiked and spiked) which had higher calcium carbonate content. The results indicated the presence of heavy metals in soils generally decreased the solution pH and pHBC values in spiked samples. In general, solubility of Ca, Mg, and K decreased with increasing equilibrium pH of non-spiked and spiked soil samples. In the case of P, increasing the pH to about 7, decreased the solubility in all soils but further increase of pH from 7, enhanced P solubility. The solubility trends and values for Ca, Mg, and K did not differed significantly in non-spiked and spiked samples. But in the case of P, a reduction in solubility was observed in heavy metal-spiked soils. The information obtained in this study can be useful to make better estimation of the effects of soil pollutants on anion and cation solubility from agricultural and environmental viewpoints.

  3. Long-term manure amendment increases organic C storage and stabilization in Loess soil

    Liang, B.; Zhao, W.; Yang, X.; Zhou, J.


    Soil is the largest terrestrial pool for organic carbon in the biosphere. Therefore, sequestration of C in soils is often seen as a 'win-win' proposition. The long-term combined application of manure with chemical fertilizers had increased the accumulation of organic carbon in soil (SOC); and the results from the application of chemical fertilizers on the stock of SOC in soil were inconsistent. Furthermore, less studies have been conducted to evaluate the effect of different fertilization, especially the application of N fertilizer, on the stabilization of SOC in the different fertilized soils. In this study, we hypothesized that the long-term different fertilization not only affect organic C storage, but also its stabilization in soil. Therefore, we conducted an incubation experiment with the soils from a long-term fertilization trials. Soil samples were collected from the three fertilized plots, ((1) no fertilizer, NF soil, (2) inorganic NPK fertilizers, NPK soil; and (3) Manure + NPK fertilizers, MNPK soil) of a long-term fertilization experiment initiated in 1990 in Shaanxi, China. The soils were incubated at 28o C for 30 days with the different treatments, i.e., (1) control with no addition (CK), (2) added 200 mg N kg-1 soil (+ NH4-N), (3) added 1000 mg C kg-1 soil (+ glucose), and (4) added 200 mg N kg-1 soil + 1000 mg C kg-1 soil (+glucose + NH4-N). The evolved CO2 was determined by titration of the excess NaOH with 0.1 M HCl. Decomposition of SOC in the different soils was evaluate with the accumulation of released CO2-C based on dry soil (in mg C kg-1 soil), and the decomposition rate of SOC during the incubation (in % of total organic C in soil). Long-term different fertilization treatments (NPK, and MNPK soil) significantly increased the organic C storage in 0-100 cm soil profile. SOC storage in MNPK soil (83.0 t ha-1) was significantly higher than NPK soil (80.8 t ha-1), and both were significantly higher than the no fertilizer soil. The decomposition

  4. Non-resonant microwave absorption studies of superconducting MgB2 and MgB2 + MgO

    Janhavi P Joshi; Subhasis Sarangi; A K Sood; Dilip Pal; S V Bhat


    Non-resonant microwave absorption (NRMA) studies of superconducting MgB2 and a sample containing ∼ 10% by weight of MgO in MgB2 are reported. The NRMA results indicate near absence of intergranular weak links in the pure MgB2 sample. A linear temperature dependence of the lower critical field c1 is observed indicating a non- wave superconductivity. However, the phase reversal of the NRMA signal which could suggest wave symmetry is also not observed. In the MgB2 + MgO sample, much larger low field dependent absorption is observed indicating the presence of intergranular weak links. The hysteretic behavior of NRMA is compared and contrasted in the two samples. In the pure MgB2 sample, a large hysteresis is observed between the forward and the reverse scans of the magnetic field indicating strong pinning of flux lines. This hysteresis saturates a few degrees below c while in the MgB2 + MgO sample, a much slower increase of hysteresis with decreasing temperature is observed, a signature of weaker pinning.

  5. Elevated temperature properties of Mg- 12Li-Al-MgO composites

    WEI Xiao-wei; HUANG Qing-min


    The compressive creep of Mg-12Li-Al-MgO particulate composites was investigated, which were produced by the reaction of reinforcement materials (B2O3) with Mg-12Li-Al alloy melt in the temperature range of 100-190 ℃ and under different compressive stress in the range of 40-70 MPa with special apparatus. The content of MgO particulates is about 0, 5%, 10%,15%(volume fraction) in Mg-12Li-Al alloy respectively. The results reveal that the creep resistance of the particulate composites is increased with increasing the content of MgO particulates and considerable improvementin creep resistance is observed in Mg-12Li-Al-MgO composites. However, over all range of temperatures and stresses, the creep data for these composites can be correlated using an empirical equation εs =Aσnexp(-Q/RT), where n is 4.93 and Q is about 78.1 kJ/mol for Mg-14Li-Al alloy and n is between 7.48 and 9.47 and Q is 111.2-137.3 kJ/mol for Mg-12Li-Al-MgO composites. The different compressive creep behavior of the composites is associated with the different material constant A. The compressive creep rate is controlled by the lattice diffusion of Li and dislocation climb.

  6. The effects of increased phosphorus application on shoot dry matter ...



    Sep 6, 2010 ... with five rates of P (0, 30, 60, 90 and 120 mg kg-1 soil). Compared to the control ... Zn deficiency as being the main cause of reduced shoot growth. In maize, the reduction in ..... Jones JB, Wolf B, Mills HA (1991). Plant Analysis ...

  7. Confinement of Mg-MgH2 systems into carbon nanotubes changes hydrogen sorption energetics.

    Liang, Jian-jie; Kung, W-C Paul


    The density functional theory (DFT) method was used to study the effect of nanoconfinement on the energetics of Mg-MgH2 systems. Varying levels of loading of the Mg/MgH2 particles into a (10,10) carbon nanotube were examined, and the corresponding energetics were computed. A clear trend was observed that, as the level of loading increases (increasing confinement), the net energy change in the hydrogen sorption/desorption processes decreases to a significant level when the loading approaches the maximum. The confinement was found not to depend on the tube length of the confining nanotubes.

  8. The Mg impurity in nitride alloys

    Zvanut, M. E.; Willoughby, W. R.; Sunay, U. R. [Department of Physics, University of Alabama at Birmingham, Birmingham AL (United States); Koleske, D. D.; Allerman, A. A. [Sandia National Laboratory, Albuquerque NM (United States); Wang, Ke; Araki, Tsutomu [Department of Photonics, Ritsumeikan University, Kusatsu, Shiga (Japan); Nanishi, Yasushi [Department of Photonics, Ritsumeikan University, Kusatsu, Shiga, Japan and WCU Program, Department of Materials Science and Engineering, Seoul National University, Seoul (Korea, Republic of)


    Although several magnetic resonance studies address the Mg acceptor in GaN, there are few reports on Mg doping in the alloys, where hole production depends strongly on the Al or In content. Our electron paramagnetic resonance (EPR) measurements of the p-type alloys suggest that the Mg impurity retains the axial symmetry, characteristic of a p-type dopant in both alloys; however, In and Al produce additional, different characteristics of the acceptor. In InGaN, the behavior is consistent with a lowering of the acceptor level and increasing hole density as In concentration increases. For AlGaN, the amount of neutral Mg decreases with increasing Al content, which is attributed to different kinetics of hydrogen diffusion thought to occur in samples with higher Al mole fraction.

  9. Lipid peroxidation in the liver of rats treated with V and/or Mg in drinking water.

    Scibior, Agnieszka; Zaporowska, Halina; Niedźwiecka, Irmina


    revealed that the changes in LPO induced by in vitro treatment of liver supernatants with exogenous Fe or V or Mg (600, 800 and 1000 microm) were a consequence of independent action of those metals and they also resulted from the interactions between Fe(exog) and V(end) and between V(end) and V(exog). In conclusion, V consumed by the rats with drinking water at a dose of 12 mg V kg(-1) body weight per 24 h for 12 weeks decreased TAS and enhanced spontaneous LPO in the hepatic tissue, which confirms its pro-oxidant potential, was also found in in vitro conditions with regard to LPO. Mg administered to rats in combination with V, at the concentration used, neither reduced nor intensified the basal LPO, compared with V-only treated animals; however, its stimulating effect on LPO was revealed in in vitro conditions, which requires further study.

  10. Rice straw incorporated just before soil flooding increases acetic acid formation and decreases available nitrogen

    Ronaldir Knoblauch


    before, the concentration of N-NH4+ in the soil was 28 and 54 mg kg-1, equivalent to an accumulation of 42 and 81 kg ha-1 of N-NH4+, respectively. There was formation of acetic acid in which toxic concentrations were reached (7.2 mmol L-1 on the 15th day of flooding only for the treatment with straw incorporated on the day of flooding. The pH of the soil solution of all the treatments increased after flooding and this increase was faster in the treatments with incorporation of straw, followed by the ash treatment and then the control. After 60 days of flooding, however, the pH values were around 6.5 for all treatments, except for the control, which reached a pH of 6.3. Rice straw should be incorporated into the soil at least 30 days before flooding; otherwise, it may immobilize part of the mineral N and produce acetic acid in concentrations toxic to rice seedlings.

  11. MgH{sub 2} as dopant for improved activation of commercial Mg ingot

    Jain, P., E-mail: [Hydrogen Research Institute, Université du Québec à Trois-Rivières, 3351 des Forges, Trois-Rivières, Québec G9A 5H7 (Canada); Lang, J. [Hydrogen Research Institute, Université du Québec à Trois-Rivières, 3351 des Forges, Trois-Rivières, Québec G9A 5H7 (Canada); Skryabina, N.Y. [Department of Physics, Perm State University, 15, Bukireva, 614990 Perm (Russian Federation); Fruchart, D. [Institut Néel, BP 166, 38042 Grenoble Cedex 9 (France); Santos, S.F [CECS, Federal University of ABC, Rua Santa Adélia 166, Santo André, SP 09210-170 (Brazil); Binder, K.; Klassen, T. [Institute of Materials Technology, Helmut-Schmidt-University, University of the Federal Armed Forces, Holstenhofweg 85, 22043 Hamburg (Germany); Huot, J., E-mail: [Hydrogen Research Institute, Université du Québec à Trois-Rivières, 3351 des Forges, Trois-Rivières, Québec G9A 5H7 (Canada)


    Highlights: •We propose a simple method to reduce production cost of light weight materials for hydrogen storage applications. •Cheaper Mg ingot rather than expensive MgH{sub 2} is used as starting material. •Effect of MgH{sub 2} as catalytic powder for improved activation behavior of Mg is demonstrated. -- Abstract: In this paper, we propose a method to decrease the activation time (first hydrogenation) of commercial Mg. This new alternative processing route uses a combination of cold rolling and short time ball milling to obtain full hydrogen capacity quickly in the first hydrogenation. As ball milling of ductile materials leads to particle agglomeration, brittle Mg plates produced by repetitive cold rolling were used as starting material. These rolled plates were then ball milled for 30 min with and without the addition of 5 wt% Mg or MgH{sub 2} powders. All the synthesized samples were investigated for hydrogen storage, absorption–desorption behavior and microstructure using X-ray diffraction (XRD), Scanning Electron Microscopy (SEM) and pressure-composition temperature (PCT) methods. Results showed slow activation behavior for cold rolled Mg plates, which was slightly improved after milling. Further improvement was obtained by adding 5 wt% of Mg powder during ball milling. In contrast, when the plates were ball milled with 5 wt% of MgH{sub 2} powder a drastic improvement in activation behavior was observed with hydrogen capacity reaching up to 6.2 wt% in comparison to 2.74 wt% for undoped and 3.57 wt% for Mg doped samples. These results reveal that ball milling with ductile Mg powder deforms only the surface of Mg plates while brittle MgH{sub 2} powders causes fracturing and cracks, increasing the surface area and generating heterogeneous nucleation sites within the bulk material.

  12. Hyperaccumulation of metals by Thlaspi caerulescens as affected by root development and Cd-Zn/Ca-Mg interactions.

    Saison, Carine; Schwartz, Christophe; Morel, Jean-Louis


    The aim of this work was to study, in a rhizobox experiment, the phytoextraction of metals by the hyperaccumulator plant Thlaspi caerulescens in relation to the heterogeneity of metal pollution. Six treatments were designed with soils containing various levels of metals. Homogeneous soils and inclusions of soils in other soil matrices were prepared in order to vary metal concentration and localization. Growth parameters of the plant (rosette diameter and shoot biomass) and localization of roots and shoot uptake of Zn, Cd, Ca, and Mg were determined after 10 weeks of growth. The plants grown on the polluted industrial soils provided a larger biomass and had lower mortality rates than those grown on the agricultural soil. Moreover, these plants accumulated more Zn and Cd (up to 17,516 and 375 mg kg(-1) DM, respectively) than plants grown on the agricultural soil (up to 7300 mg Zn kg(-1) and 83 mg Cd kg(-1) DM). The roots preferentially explored metal-contaminated areas. The exploration of polluted soil inclusions by the roots was associated with a higher extraction of metals. Zinc and Cd in the shoots of Thlaspi caerulescens were negatively correlated with Ca and Mg concentrations; however, the soil supply for these two elements was identical. This suggests that there is competition for the uptake of these elements and that Zn is preferentially accumulated.

  13. Increased strontium uptake in trabecular bone of ovariectomized calcium-deficient rats treated with strontium ranelate or strontium chloride.

    Pemmer, Bernhard; Hofstaetter, Jochen G; Meirer, Florian; Smolek, Stephan; Wobrauschek, Peter; Simon, Rolf; Fuchs, Robyn K; Allen, Matthew R; Condon, Keith W; Reinwald, Susan; Phipps, Roger J; Burr, David B; Paschalis, Eleftherios P; Klaushofer, Klaus; Streli, Christina; Roschger, Paul


    Based on clinical trials showing the efficacy to reduce vertebral and non-vertebral fractures, strontium ranelate (SrR) has been approved in several countries for the treatment of postmenopausal osteoporosis. Hence, it is of special clinical interest to elucidate how the Sr uptake is influenced by dietary Ca deficiency as well as by the formula of Sr administration, SrR versus strontium chloride (SrCl(2)). Three-month-old ovariectomized rats were treated for 90 days with doses of 25 mg kg(-1) d(-1) and 150 mg kg(-1) d(-1) of SrR or SrCl(2) at low (0.1% Ca) or normal (1.19% Ca) Ca diet. Vertebral bone tissue was analysed by confocal synchrotron-radiation-induced micro X-ray fluorescence and by backscattered electron imaging. Principal component analysis and k-means clustering of the acquired elemental maps of Ca and Sr revealed that the newly formed bone exhibited the highest Sr fractions and that low Ca diet increased the Sr uptake by a factor of three to four. Furthermore, Sr uptake in bone of the SrCl(2)-treated animals was generally lower compared with SrR. The study clearly shows that inadequate nutritional calcium intake significantly increases uptake of Sr in serum as well as in trabecular bone matrix. This indicates that nutritional calcium intake as well as serum Ca levels are important regulators of any Sr treatment.

  14. Sulfate and chromate increased each other's uptake and translocation in As-hyperaccumulator Pteris vittata.

    de Oliveira, Letúzia M; Gress, Julia; De, Jaysankar; Rathinasabapathi, Bala; Marchi, Giuliano; Chen, Yanshan; Ma, Lena Q


    We investigated the effects of chromate (CrVI) and sulfate on their uptake and translocation in As-hyperaccumulator Pteris vittata. Plants were exposed to 1) 0.1 mM CrVI and 0, 0.25, 1.25 or 2.5 mM sulfate or 2) 0.25 mM sulfate and 0, 0.5, 2.5 or 5.0 mM CrVI for 1 d in hydroponics. P. vittata accumulated 26 and 1261 mg kg(-1) Cr in the fronds and roots at CrVI0.1, and 2197 and 1589 mg kg(-1) S in the fronds and roots at S0.25. Increasing sulfate concentrations increased Cr root concentrations by 16-66% and helped CrVI reduction to CrIII whereas increasing CrVI concentrations increased frond sulfate concentrations by 3-27%. Increasing sulfate concentrations enhanced TBARS concentrations in the biomass, indicating oxidative stress caused lipid peroxidation in plant cell membranes. However, addition of 0.25-2.5 mM sulfate alleviated CrVI's toxic effects and decreased TBARS from 23.5 to 9.46-12.3 μmol g(-1) FW. Though CrVI was supplied, 78-96% of CrIII was in the biomass, indicating efficient CrVI reduction to CrIII by P. vittata. The data indicated the amazing ability of P. vittata in Cr uptake at 289 mg kg(-1) h(-1) with little translocation to the fronds. These results indicated that P. vittata had potential in Cr phytoremediation in contaminated sites but further studies are needed to evaluate this potential. The facts that CrVI and sulfate helped each other in uptake by P. vittata suggest that CrVI was not competing with sulfate uptake in P. vittata. However, the mechanisms of how sulfate and CrVI enhance each other's accumulation in P. vittata need further investigation.

  15. Melting relations in the MgO-MgSiO3 system up to 70 GPa

    Ohnishi, Satoka; Kuwayama, Yasuhiro; Inoue, Toru


    Melting experiments in a binary system MgO-MgSiO3 were performed up to 70 GPa using a CO2 laser heated diamond anvil cell. The quenched samples were polished and analyzed by a dualbeam focused ion beam (FIB) and a field emission scanning electron microscope (FE-SEM), respectively. The liquidus phase and the eutectic composition were determined on the basis of textual and chemical analyses of sample cross sections. Our experimental results show that the eutectic composition is the Si/Mg molar ratio of 0.76 at 35 GPa and it decreases with increasing pressure. Above 45 GPa, it becomes relatively constant at about 0.64-0.65 Si/Mg molar ratio. Using our experimental data collected at a wide pressure range up to 70 GPa together with previous experimental data, we have constructed a thermodynamic model of the eutectic composition of the MgO-MgSiO3 system. The eutectic composition extrapolated to the pressure and temperature conditions at the base of the mantle is about 0.64 Si/Mg molar ratio. The modeled eutectic composition is quite consistent with a previous prediction from ab initio calculations (de Koker et al. in Earth Planet Sci Lett 361:58-63, 2013), suggesting that the simple assumption of a non-ideal regular solution model can well describe the melting relation of the MgO-MgSiO3 system at high pressure. Our results show that the liquidus phase changes from MgO-periclase to MgSiO3-bridgmanite at 35 GPa for the simplified pyrolite composition ( 0.7 Si/Mg molar ratio), while MgSiO3-bridgmanite is the liquidus phase at the entire lower mantle conditions for the chondritic composition ( 0.84 Si/Mg molar ratio).

  16. Modification effect of lanthanum on primary phase Mg2Si in Mg-Si alloys

    WANG Liping; GUO Erjun; MA Baoxia


    The modifying effect of La addition on primary phase Mg2Si in Mg-5Si alloys was investigated. The results showed that a proper amount of La could effectively modify the primary phase Mg2Si. Based on the present experiment, the optimal modification effect was obtained with an addition of about 0.5 wt.% La. The size of the primary phase Mg2Si was considerably reduced to 25 μm or less and the morphology was modified from a coarse dendritic shape to a polyhedral shape. However, when the addition of La increased to 0.8 wt.% or higher, the primary Mg2Si grew into a coarse dendritic morphology again. Moreover, it was found that some LaSi2 compounds were formed during solidification and the amount of the compounds appeared to increase gradually with increasing La content.

  17. Comparison of rizatriptan 5 mg and 10 mg tablets and sumatriptan 25 mg and 50 mg tablets.

    Kolodny, A; Polis, A; Battisti, W P; Johnson-Pratt, L; Skobieranda, F


    This randomized, double-blind, two-attack, placebo-controlled, crossover study explored the efficacy and tolerability of rizatriptan 10 mg compared with sumatriptan 50 mg as well as rizatriptan 5 mg compared with sumatriptan 25 mg in the acute treatment of migraine. Following randomization to one of six possible treatment sequences, patients (n = 1447) treated two sequential attacks, of moderate or severe intensity, separated by at least 5 days. Patients assessed pain severity, migraine-associated symptoms, and functional disability at 0.5, 1, 1.5, and 2 h post treatment. Compared with placebo, all treatments were effective. On the primary endpoint of time to pain relief, rizatriptan 10 mg was not statistically different from sumatriptan 50 mg [odds ratio (OR) 1.10, P = 0.161], and rizatriptan 5 mg was statistically superior to sumatriptan 25 mg (OR 1.22, P = 0.007). In general, rizatriptan 10 mg and 5 mg treatment resulted in improvement compared with the corresponding doses of sumatriptan on measures of pain severity, migraine symptoms, and functional disability and the 5-mg dose reached statistical significance on almost all measures. All treatments were generally well tolerated.

  18. Heavy Metals (Mg, Mn, Ni and Sn contamination in Soil Samples of Ahvaz II Industrial Estate of Iran in 2013

    Soheil l Sobhanardakani


    Full Text Available Background & Aims of the Study: Due to the rapid industrial development in Khuzestan province of Iran during recent years, this study was performed to analyze the variation of metals concentrations (Mg, Mn, Ni, and Sn in soil samples of Ahvaz II Industrial estate during the spring season of 2013. Materials & Methods: In this experimental study, 27 topsoil samples were collected from nine stations. The intensity of the soil contamination was evaluated, using a contamination factor (Cf and geo-accumulation index (I-geo. Results:  The mean soil concentrations (in mg kg-1 (dry weight were in ranged within 870-1144 (Mg, 188-300 (Mn, 93-199 (Ni and 9-15 (Sn. The data indicated that the I-geo value for all metals falls in class ‘1’. Also the Cf value for Mg and Mn falls in class ‘0’, the Cf value for Sn falls in class ‘1’ and the Cf value for Ni falls in the classes of ‘1’ and ‘2’. The result of the Pearson correlation showed that there were significant positive associations between all metals. Conclusions: According to the results which were achieved by a cluster analysis, there were significant positive associations among all metals based on Pearson correlation coefficient, especially between Ni and Sn; also both of them with Mn. Because the Ni originates from oil sources it can be resulted that Mn and Sn originate from oil sources, too. Therefore, industrial activities and exploitation of oil reservoirs are the main cause of pollution in that area. Also, it can be concluded that, with increasing the distance from the source of pollution, the accumulation of contaminants in the soil samples decreased.

  19. Substitution of Mn for Mg in MgB_2*

    Fitzpatrick, Michael D.; Johnston, David C.; Miller, Lance L.; Hill, Julienne M.


    The study of solid solutions in which the Mg in MgB2 is partially replaced by magnetic 3d or 4f atoms can potentially reveal important information on the superconducting state of MgB_2. As an end-member of the hypothetical Mg_1-xMn_xB2 system, MnB2 is isostructural with MgB2 and is an antiferromagnet below TN = 760 K which becomes canted at 157 K. A previous study by Moritomo et al.[1] examined the structure and properties of multi-phase samples with 0.01J. Phys. Soc. Japan b70, 1889 (2001).; “Effects of transition metal doping in MgB2 superconductor", Y. Moritomo at al. arXiv:cond-mat/0104568.

  20. Mesoporous carbon stabilized MgO nanoparticles synthesized by pyrolysis of MgCl2 preloaded waste biomass for highly efficient CO2 capture.

    Liu, Wu-Jun; Jiang, Hong; Tian, Ke; Ding, Yan-Wei; Yu, Han-Qing


    Anthropogenic CO2 emission makes significant contribution to global climate change and CO2 capture and storage is a currently a preferred technology to change the trajectory toward irreversible global warming. In this work, we reported a new strategy that the inexhaustible MgCl2 in seawater and the abundantly available biomass waste can be utilized to prepare mesoporous carbon stabilized MgO nanoparticles (mPC-MgO) for CO2 capture. The mPC-MgO showed excellent performance in the CO2 capture process with the maximum capacity of 5.45 mol kg(-1), much higher than many other MgO based CO2 trappers. The CO2 capture capacity of the mPC-MgO material kept almost unchanged in 19-run cyclic reuse, and can be regenerated at low temperature. The mechanism for the CO2 capture by the mPC-MgO was investigated by FTIR and XPS, and the results indicated that the high CO2 capture capacity and the favorable selectivity of the as-prepared materials were mainly attributed to their special structure (i.e., surface area, functional groups, and the MgO NPs). This work would open up a new pathway to slow down global warming as well as resolve the pollution of waste biomass.

  1. Structural and electronic properties of Mg and Mg-Nb co-doped TiO2 (101) anatase surface

    Sasani, Alireza; Baktash, Ardeshir; Mirabbaszadeh, Kavoos; Khoshnevisan, Bahram


    In this paper, by using density functional theory, Mg and Nb-Mg co-doping of TiO2 anatase (101) surfaces are studied. By studying the formation energy of the defects and the bond length distribution of the surface, it is shown that Mg defects tend to stay as far as possible to induce least possible lattice distortion while Nb and Mg defects stay close to each other to cause less stress to the surface. By investigating band structure of the surface and changes stemmed from the defects, potential effects of Mg and Mg-Nb co-doping of TiO2 surface on dye-sensitized solar cells are investigated. In this study, it is shown that the Nb-Mg co-doping could increase JSC of the surface while slightly decreasing VOC compared to Mg doped surface, which might result in an increase in efficiency of the DSSCs compared to Nb or Mg doped surfaces.

  2. Avaliação de contaminação por mercúrio em Descoberto, MG Evaluation of mercury contamination in Descoberto, MG

    Ana Amélia Paulino Tinôco


    Full Text Available O mercúrio, elemento químico considerado não essencial a qualquer processo metabólico, é facilmente acumulado na maioria dos organismos. Ocorre naturalmente em formas orgânicas e inorgânicas, nos estados sólido, dissolvido e gasoso. Seu ciclo biogeoquímico envolve processos que ocorrem no solo, na água e na atmosfera. Em 2002, descobriu-se mercúrio elementar na zona rural do município de Descoberto, Minas Gerais, onde moram cerca de 70 famílias, e sua origem parece estar associada à exploração de ouro, que existiu na região no século 19. Neste trabalho, foram escolhidas três áreas para identificar possível contaminação da água, solo, sedimento e peixes por mercúrio, bem como para estabelecer valores de referência local e contraprova de resultados obtidos anteriormente. Verificaram-se elevadas concentrações no solo (0,26 a 0,55, sedimentos (0,13 a 0,61 e água (Mercury is a chemical element considered unessential to any metabolic process; however, it is easily accumulated in most organisms. It is naturally found in both organic and inorganic forms in solid, liquid and vapor states. Its biogeochemical cycle involves processes occurring in the soil, water and the atmosphere. In 2002, elementary mercury was found in the city of Descoberto, Minas Gerais, Brazil, where 70 families live, and its origin may be related to gold exploration that happened in this region in the 19th century. In this work, three areas were chosen to identify a possible mercury contamination of water, soil, sediment and fish samples and to establish local reference values and counter-evidence of the data previously obtained. Based on the results, high mercury concentrations in soil (0.26 to 0.55, sediments (0.13 to 0.61 and water (< 0.2 to 2,10 µg.L-1 were verified.

  3. Effect of Mg and C contents in MgCNi3, and structure and superconductivity of MgCNi3-xCox


    The effect of Mg and C contents on TC in MgCNi3, and structure and superconductivity of MgCNi3-xCox were studied. It is found that the excess of Mg and C in initial material mixture is favorable to improvement in TC and helps to obtain single_phase samples. For preparing MgCNi3 superconductor, the optimum composition of starting materials is MgC1.45Ni3 with excess of Mg (20 wt.%) of the stoichiometric composition. In MgCNi3-xCox system, a continuous solid solution is formed, lattice parameter decreases slightly and TC decreases obviously with increasing x. A suppression of superconductivity is observed due to the substitution of Co (Mn) for Ni. The suppression effect is smaller for the substitution of Co than that of Mn.

  4. Phase transition and optoelectronic properties of MgH2

    Nayak, Vikas; Verma, U. P.


    In this article, structural and electronic properties of MgH2 have been studied. The aim behind this study was to find out the ground state crystal structure of MgH2. For the purpose, density functional theory (DFT)-based full-potential linearized augmented plane wave (FP-LAPW) calculations have been performed in three different space groups: P42/mnm (α-MgH2), Pa3 (β-MgH2) and Pbcn (γ-MgH2). It has been found that the ground state structure of MgH2 is α-MgH2. The present study shows that α-MgH2 transforms into γ-MgH2 at a pressure of 0.41 GPa. After further increase in pressure, γ-MgH2 transforms into β-MgH2 at a pressure of 3.67 GPa. The obtained results are in good agreement with previously reported experimental data. In all the studied phases, the behavior of MgH2 is insulating and its optical conductivity is around 6.0 eV. The α-MgH2 and γ-MgH2 are anisotropic materials while β-MgH2 is isotropic in nature.

  5. Aqueous magnesium ion battery based on carbon-coated FeVO4 as anode and Mg-OMS-1 as cathode with high energy density.

    Zhang, Hongyu; Ye, Ke; Zhu, Kai; Cang, Ruibai; Yan, Jun; Cheng, Kui; Wang, Guiling; Cao, Dianxue


    The porous FeVO4 is prepared by hydrothermal method and further modified by coating carbon to obtain the FeVO4/C with hierarchical pore structure, which are used as anodic electrodes in aqueous rechargeable magnesium ion battery. And the FeVO4/C material can not only improve the electrical conductivity by coating a carbon layer but also increase the specific surface area by hierarchical pore structure, which is more beneficial for magnesium ion insertion/deinsertion. Therefore, the aqueous rechargeable magnesium ion full battery is successfully constructed by FeVO4/C as anode, Mg-OMS-1 as cathode and in 1.0 mol L-1 MgSO4 as electrolyte. The discharge capacity of Mg-OMS-1 // FeVO4/C aqueous battery can be obtained 58.9 mAh g-1 at the current density of 100 mA g-1 by calculating the total mass of two electrodes and the capacity retention rate of this device is 97.7% after 100 cycles with the nearly 100% coulombic efficiency, which indicates that the system owns a good electrochemical reversibility. More than that, this system can achieve a high energy density of 70.4 Wh kg-1, which provides a powerful evidence to make the aqueous magnesium ion battery possible. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Nodulation by Sinorhizobium meliloti originated from a mining soil alleviates Cd toxicity and increases Cd-phytoextraction in Medicago sativa L.

    Tahar eGhnaya


    Full Text Available Besides their role in nitrogen supply to the host plants by the process of symbiotic N fixation, the association between legumes and Rhizobium could be interesting also for the rehabilitation of metal contaminated soils by phytoextraction. A major limitation is however the metal sensitivity of the bacterial strains. The aim of this work was to explore the usefulness of Sinorhizobium meliloti originated from a mining site in phytoextraction of Cd by Medicago sativa. Inoculated and non-inoculated plants were cultivated for 60 d on soils containing 50 or 100 mg Cd kg-1 soil. The inoculation hindered the occurrence of Cd- induced toxicity symptoms that appeared in the shoots of non-inoculated plants. This positive effect of S.meliloti colonization was accompanied by an increase in biomass production and improved nutrient acquisition as compared to non-inoculated plants. Moreover, nodulation enhanced both Cd absorption by the roots and Cd transloaction to the shoots. The amelioration of plant biomass concomitantly with the increase in Cd shoot concentration in inoculated plants led to higher potential of Cd-phytoextraction in these plants. Hence, in the presence of 50 mg Cd kg-1 in the soil, the quantities of Cd extracted in the shoots were 58 and 178 µg plant-1 in non-inoculated and inoculated plants, respectively. Thus we suggest that this association M. sativa-S. meliloti is an efficient biological system to extract Cd.

  7. Efeitos do manganês sobre a soja cultivada em solo de Cerrado do Triângulo Mineiro Effects of manganese on soybean growth in a cerrado soil of Triângulo Mineiro, MG, Brazil



    Full Text Available A deficiência de Mn em soja [Glycine max (L. Merrill] e em outras culturas pode ser devida aos seus baixos teores no solo, ou à indisponibilidade do elemento induzida pela aplicação de calcário. O objetivo deste trabalho foi verificar a composição mineral da soja em relação à disponibilidade de Mn no solo. Em casa de vegetação foi conduzido um experimento utilizando um solo coletado no município de Patrocínio, MG, onde o café mostra sintomas de deficiência desse elemento. As doses de Mn foram: 0, 10, 50 e 100 mg kg-1 e um tratamento adicional com aplicação foliar de 0,6% de Mn e duas doses de calcário, ou seja: 0 e 2,7 t ha-1. Os teores de Mn na planta aumentaram com a dose de Mn no solo, e diminuíram com a aplicação de calcário. O menor teor de Mn encontrado nas folhas foi de 84 mg kg-1 na dose 0 de Mn com calcário. O Mn provocou um aumento na produção de matéria seca e de vagens, em relação a ambas as doses de calcário. A calagem não induziu o aparecimento de sintomas de deficiência de Mn. A aplicação foliar de Mn foi eficiente em aumentar e manter a produção.Manganese deficiency in soybean [Glycine max (L. Merrill and in other crops could be due to its low levels in the soil, or to its unavailability induced by liming. The objective of this research was to verify the soybean mineral composition in relation to Mn availability. An experiment was carried out in a greenhouse, using soil from Patrocínio, MG, Brazil, where the cultivated coffee shows symptoms of Mn deficiency. Mn was applied at the rates of zero, 10, 50 and 100 mg kg-1 with an additional treatment of 0.6% of foliar applied Mn and two rates of lime, namely: zero and 2.7 t ha-1. Mn concentration in the plant tissue was increased with the rate of lime application; liming, however, caused a Mn reduction. It must be pointed out that the lowest Mn level in the leaves was 84 mg kg-1, at the zero rate of Mn with lime. Mn ratio caused an increase both in

  8. Chronic vasodilation increases renal medullary PDE5A and α-ENaC through independent renin-angiotensin-aldosterone system pathways.

    West, Crystal A; Shaw, Stefan; Sasser, Jennifer M; Fekete, Andrea; Alexander, Tyler; Cunningham, Mark W; Masilamani, Shyama M E; Baylis, Chris


    We have previously observed that many of the renal and hemodynamic adaptations seen in normal pregnancy can be induced in virgin female rats by chronic systemic vasodilation. Fourteen-day vasodilation with sodium nitrite or nifedipine (NIF) produced plasma volume expansion (PVE), hemodilution, and increased renal medullary phosphodiesterase 5A (PDE5A) protein. The present study examined the role of the renin-angiotensin-aldosterone system (RAAS) in this mechanism. Virgin females were treated for 14 days with NIF (10 mg·kg(-1)·day(-1) via diet), NIF with spironolactone [SPR; mineralocorticoid receptor (MR) blocker, 200-300 mg·kg(-1)·day(-1) via diet], NIF with losartan [LOS; angiotensin type 1 (AT1) receptor blocker, 20 mg·kg(-1)·day(-1) via diet], enalapril (ENAL; angiotensin-converting enzyme inhibitor, 62.5 mg/l via water), or vehicle (CON). Mean arterial pressure (MAP) was reduced 7.4 ± 0.5% with NIF, 6.33 ± 0.5% with NIF + SPR, 13.3 ± 0.9% with NIF + LOS, and 12.0 ± 0.4% with ENAL vs. baseline MAP. Compared with CON (3.6 ± 0.3%), plasma volume factored for body weight was increased by NIF (5.2 ± 0.4%) treatment but not by NIF + SPR (4.3 ± 0.3%), NIF + LOS (3.6 ± 0.1%), or ENAL (4.0 ± 0.3%). NIF increased PDE5A protein abundance in the renal inner medulla, and SPR did not prevent this increase (188 ± 16 and 204 ± 22% of CON, respectively). NIF increased the α-subunit of the epithelial sodium channel (α-ENaC) protein in renal outer (365 ± 44%) and inner (526 ± 83%) medulla, and SPR prevented these changes. There was no change in either PDE5A or α-ENaC abundance vs. CON in rats treated with NIF + LOS or ENAL. These data indicate that the PVE and renal medullary adaptations in response to chronic vasodilation result from RAAS signaling, with increases in PDE5A mediated through AT1 receptor and α-ENaC through the MR.

  9. P2X7 Receptor Mediated Growth-Inhibitory Effect in KG1 a Cell Line

    Xiujun Zhang; Lijun Meng


    This study was conducted to investigate ATP-induced growth inhibition in human leukemic cells KGla.METHoDS ATP inhibited cell growth was analyzed by MTSassay.Extemalization of phosphatidylserine could be detected byAnnexin-V-FITC apoptosis staining after activation of the P2X7 re-ceptor.P2X7 mediated pore formation was detected in KGla cellsby Yo-Pro-1 uptake assay.RESUlTS ATP inhibited cell growth in a dose-dependent man-ner.The cytotoxic effect could be blocked by P2X7 antagonists,oxidized ATP(OATP)and KN62.Externalization of phosphatidyl-serine could be detected in a time-dependent manner.P2X7 medi-ated pore forigation could be detected in KGla cells.These effectscould not be observed in P2X7 null Ramos cells.CONCLUSIoN The results and our previously reports thatmRNA,protein expression and calcium response of the P2X7receptor in KGla cells,suggested that extracellular ATP effectivelyinduces growth inhibition through apoptosis in KGla cells byactivation of P2X7 receptor,and that may be mediated by extracel-lular Ca2+ineux and pore formation.

  10. Albumin synthesis in humans increases immediately following the administration of endotoxin.

    Barle, Hans; Januszkiewicz, Anna; Hållström, Lars; Essén, Pia; McNurlan, Margaret A; Garlick, Peter J; Wernerman, Jan


    In order to investigate the immediate (i.e. within 3 h) response of albumin synthesis to the administration of endotoxin, as a model of a moderate and well controlled catabolic insult, two measurements employing L-[(2)H(5)]phenylalanine were performed in 16 volunteers. One group ( n =8) received an intravenous injection of endotoxin (4 ng/kg; lot EC-6) immediately after the first measurement of albumin synthesis, whereas the other group received saline. A second measurement was initiated 1 h later. In the endotoxin group, the fractional synthesis rate of albumin was 6.9+/-0.6%/day (mean+/-S.D.) in the first measurement. In the second measurement, a significant increase was observed (9.6+/-1.2%/day; P <0.001). The corresponding values in the control group were were 6.6+/-0.6%/day and 7.0+/-0.6%/day respectively (not significant compared with first measurement and P <0.001 compared with the second measurement in the endotoxin group). The absolute synthesis rates of albumin were 148+/-35 and 201+/-49 mg x kg(-1) x day(-1) before and after endotoxin ( P <0.01). In the control group, the corresponding values were 131+/-21 and 132+/-20 mg x kg(-1) x day(-1) (not significant compared with the first measurement and P <0.01 compared with the second measurement in the endotoxin group). In conclusion, these results indicate that albumin synthesis increases in the very early phase after a catabolic insult, as represented by the administration of endotoxin.

  11. Rilmenidine prevents blood pressure increase in rats with compromised nitric oxide production

    Mária GEROV(A); Jozef T(O)R(O)K; Ol'ga PECH(A)(O)OV(A); Jana MATU(S)KOV(A)


    AIM: To search tools of high blood pressure in the model of nitric oxide (NO)-defective hypertension, and the study focused on the effect of rilmenidine, agonist of imidazoline receptors, which was suggested to modulate central sympathetic outflow. METHODS: Three experimental groups, each consisting of 7 rats, were used: (Ⅰ) rats with inhibition of NO synthase (NOS) by NG-nitro-L-arginine methyl ester (L-NAME) 40 for 4 weeks in drinking water, (Ⅱ) rats with inhibited NOS as in group Ⅰ, plus agonist of imidazoline receptors rilmenidine·d-1 for 4 weeks by gavage, and (Ⅲ) control rats. Systolic blood pressure was measured weekly noninvasively.At the end of experiment aortic ring isometric tension was followed, NOS expression (aorta, left ventricle), and NOS activity (left ventricle and brain) were determined. RESULTS: In the group Ⅰ systolic blood pressure increased significantly, aortic ring relaxation to acetylcholine was significantly attenuated. Rilmenidine administered simultaneously with L-NAME (group Ⅱ) prevented the increase of blood pressure which did not differ significantly from control values; aortic ring relaxation to acetylcholine did not differ from control. No change in NOS expression (aorta and left ventricle) was found in groups Ⅰ and Ⅱ. Significant decline in NOS activity (left ventricle and brain) was found in groups Ⅰ and ⅡⅡ. CONCLUSION: Rilmenidine has a remarkable role in NO-defective hypertension,possibly by inhibiting central sympathetic outflow and by affecting receptors in vascular smooth muscle also. The prime cause of hypertension in this experimental model - the compromised production of NO due to inhibition of NOS - was not affected by rilmenidine.

  12. Fabrication of Mg-doped ZnO thin films by laser ablation of Zn:Mg target

    Kim, Tae Hyun; Park, Jin Jae; Nam, Sang Hwan; Park, Hye Sun; Cheong, Nu Ri [Department of Chemistry, Kyunghee University, Seoul 130-701 (Korea, Republic of); Song, Jae Kyu [Department of Chemistry, Kyunghee University, Seoul 130-701 (Korea, Republic of)], E-mail:; Park, Seung Min [Department of Chemistry, Kyunghee University, Seoul 130-701 (Korea, Republic of)], E-mail:


    Mg-doped ZnO thin films were fabricated by laser ablation of Zn:Mg targets consisting of Mg metallic strips and Zn disk in oxygen atmosphere with a goal to facilitate convenient control of Mg contents in the films. The characteristics of the deposited films were examined by analyzing their photoluminescence (PL), X-ray diffraction and X-ray photoelectron spectroscopy (XPS) spectra. Mg contents as analyzed by XPS indicate that the target composition is fairly transferred to the deposited films. The wurtzite structure of ZnO was conserved even for the highly doped ZnO films and there was no Mg- or MgO-related XRD peaks. With increase in the Mg content, the bandgap and PL peak energy shifted to blue and the Stokes shift became larger.

  13. Comparison of hydrogen storage properties of pure Mg and milled pure Mg

    Myoung Youp Song; Young Jun Kwak; Seong Ho Lee; Hye Ryoung Park


    Hydrogen storage properties of pure Mg were studied at 593 K under 12 bar H2. In order to increase the hydriding and dehydriding rates, pure Mg was ground under hydrogen atmosphere (reactive mechanical grinding, RMG) and its hydrogen storage properties were subsequently investigated. Pure Mg absorbed hydrogen very slowly. At the number of cycles () of 1, pure Mg absorbed 0.05 wt% H for 5 min, 0.08 wt% H for 10 min and 0.29 wt% H for 60 min at 593 K under 12 bar H2. Activation was completed at the fifth cycle. At = 6, pure Mg absorbed 1.76 wt% H for 5 min, 2.17 wt% H for 10 min and 3.40 wt% H for 60 min. The activation of pure Mg after RMG was completed at the sixth cycle. At = 7, pure Mg after RMG absorbed 2.57 wt% H for 5 min, 3.21 wt% H for 10 min and 4.15 wt% H for 60 min.

  14. Structural and electronic properties of Mg and Mg-Nb co-doped TiO2 (101) anatase surface

    Sasani, Alireza [Department of Science, Karaj Islamic Azad University, Karaj, Alborz, P.O. Box 31485-313 (Iran, Islamic Republic of); Baktash, Ardeshir [Institute of Nano Science and Nano Technology, University of Kashan, Kashan, P.O. Box 87317-51167 (Iran, Islamic Republic of); Mirabbaszadeh, Kavoos, E-mail: [Department of Energy Engineering and Physics, Amirkabir University of Technology, Tehran, P. O. Box 15875-4413 (Iran, Islamic Republic of); Khoshnevisan, Bahram [Institute of Nano Science and Nano Technology, University of Kashan, Kashan, P.O. Box 87317-51167 (Iran, Islamic Republic of)


    Highlights: • Formation energy of Mg and Mg-Nb co-doped TiO{sub 2} anatase surface (101) is studied. • Effect of Mg defect to the TiO{sub 2} anatase (101) surface and bond length distribution of the surface is studied and it is shown that Mg defects tend to stay far from each other. • Effect of Mg and Nb to the bond length distribution of the surface studied and it is shown that these defects tend to stay close to each other. • Effects of Mg and Mg-Nb defects on DSSCs using TiO{sub 2} anatase hosting these defects are studied. - Abstract: In this paper, by using density functional theory, Mg and Nb-Mg co-doping of TiO{sub 2} anatase (101) surfaces are studied. By studying the formation energy of the defects and the bond length distribution of the surface, it is shown that Mg defects tend to stay as far as possible to induce least possible lattice distortion while Nb and Mg defects stay close to each other to cause less stress to the surface. By investigating band structure of the surface and changes stemmed from the defects, potential effects of Mg and Mg-Nb co-doping of TiO{sub 2} surface on dye-sensitized solar cells are investigated. In this study, it is shown that the Nb-Mg co-doping could increase J{sub SC} of the surface while slightly decreasing V{sub OC} compared to Mg doped surface, which might result in an increase in efficiency of the DSSCs compared to Nb or Mg doped surfaces.

  15. Mg spin affects adenosinetriphosphate activity

    Tulub, Alexander A


    The Schlegel-Frisch ab initio molecular dynamics (ADMP) (DFT:B3LYP), T = 310 K, is used to study complexation between adenosinetriphosphate (ATP), ATP subsystem, and magnesium cofactor [Mg(H2O)6]2+, Mg subsystem, in a water pool, modeled with 78 water molecules, in singlet (S) and triplet (T) states. The computations prove that the way of ATP cleavage is governed by the electron spin of Mg. In the S state Mg prefers chelation of \\gamma-\\beta-phosphate oxygens (O1-O2), whereas in the T state it chelates \\beta-\\alpha-phosphate oxygens (O2-O3) or produces a single-bonded intermediate. Unlike the chelates, which initiate ionic reaction paths, the single-bonded intermediate starts off a free-radical path of ATP cleavage, yielding a highly reactive adenosinemonophosphate ion-radical, .AMP-, earlier observed in the CIDNP (Chemically Induced Dynamic Nuclear Polarization) experiment (A.A. Tulub, 2006). The free-radical path is highly sensitive to Mg nuclear spin, which through a hyperfine interaction favors the produc...

  16. Transition of interface oxide layer from porous Mg(OH)2 to dense MgO induced by polyaniline and corrosion resistance of Mg alloy therefrom

    Luo, Yizhong; Sun, Yang; Lv, Jinlong; Wang, Xianhong; Li, Ji; Wang, Fosong


    The feasibility of polyaniline emeraldine base (EB) for enhancing long-term corrosion resistance of magnesium alloy (AZ91D Mg alloy) was confirmed, since the complex impedance of Mg alloy protected by EB/epoxy resin (ER) composite coating with 10 wt% EB loading maintained around 2 GΩ cm2 even after 80 day exposure in 0.5 M NaCl solution, while that of pure ER coated analogue decreased to 0.17 MΩ cm2 only after 31 days. The improvement in corrosion resistance was attributed to the transition of interface layer from porous Mg(OH)2 dominated one underneath pure ER coating to dense MgO dominated one underneath EB/ER coating, induced by the redox interaction of EB with Mg alloy. When the EB loading in EB/ER coating increased from 0 to 10 wt%, the relative XPS peak area ratio of MgO to Mg(OH)2 increased from 0.78 to 1.18, indicating that EB behaved as effective corrosion inhibitor causing the transformation of oxide layer from porous Mg(OH)2 to dense MgO.

  17. CsMgPO4

    Nikolay S. Slobodyanik


    Full Text Available Caesium magnesium orthophosphate is built up from MgO4 and PO4 tetrahedra (both with . m. symmetry linked together by corners, forming a three-dimensional framework. The Cs atoms have .m. site symmetry and are located in hexagonal channels running along the a- and b-axis directions.

  18. Mg isotope fractionation during microbe-mineral interactions

    Kim, Insu; Ryu, Jong-sik; Lee, Kwang-sik; Lee, Dongho


    Magnesium is involved in various biogeochemical processes important to the global climate change over geological time-scale. Mg isotopes allow us to directly trace the Mg cycle in the Earth's surface but the factors controlling Mg isotopic compositions have not fully understood yet. Here, we conducted a batch experiment using two bacterial species (Shewanella putrefaciens and Burkholderia fungorum) and three major Mg-bearing minerals (biotite, dolomite and hornblende). All elemental concentrations increased by 336 h and then reached to steady-state values, of which Mg concentrations varied depending on minerals and bacterial species. This result indicates that the mineral dissolution is affect by the presence of microbes, which either provide organic acids or attach onto mineral surface. The Mg isotopic compositions of initial minerals biotite, dolomite and hornblende are -0.35o of biotite, -0.99o of dolomite, and -0.24o of hornblende, in δ26Mg. Similarly, δ26Mg values increased by 336 h and reached to steady-state values, which also varied with minerals and microbes. During dissolution of three minerals, the light isotope of Mg is preferentially incorporated into the dissolved phases and then the dissolved δ26Mg values become consistent with those of minerals with the time.

  19. Epinephrine-stimulated glycogen breakdown activates glycogen synthase and increases insulin-stimulated glucose uptake in epitrochlearis muscles

    Kolnes, Anders J; Birk, Jesper Bratz; Eilertsen, Einar


    Adrenaline increases glycogen synthase (GS) phosphorylation and decreases GS activity but also stimulates glycogen breakdown and low glycogen content normally activates GS. To test the hypothesis that glycogen content directly regulates GS phosphorylation, glycogen breakdown was stimulated...... in condition with decreased GS activation. Saline or adrenaline (0.02mg/100g rat) was injected subcutaneously in Wistar rats (~130 g) with low (24 h fasted), normal (normal diet) and high glycogen content (fasted-refed) and epitrochlearis muscles were removed after 3 h and incubated ex vivo eliminating...... adrenaline action. Adrenaline injection reduced glycogen content in epitrochlearis muscles with high (120.7±17.8 vs 204.6±14.5 mmol•kg(-1); p

  20. Otters Increasing - Threats Increasing

    Andreas Kranz


    Full Text Available In some parts of Central Europe populations of otters are apparently increasing. Until recently, no research was being conducted on the ecology of otters in mainly artificial habitats like fish farms. Otters are not only a new source of conflict requiring species management, but appear once again threatened by illegal hunting. Austria is dealing with this problem using compensation for otter damage, electric fencing and translocation of problem otters. Despite a rise in illegal killing, Austria does not formally recognise this as a threat.

  1. Effect of sterilization process on surface characteristics and biocompatibility of pure Mg and MgCa alloys

    Liu, X.L.; Zhou, W.R.; Wu, Y.H.; Cheng, Y. [Center for Biomedical Materials and Tissue Engineering, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871 (China); Zheng, Y.F., E-mail: [Center for Biomedical Materials and Tissue Engineering, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871 (China); State Key Laboratory for Turbulence and Complex System, College of Engineering, Peking University, Beijing 100871 (China); Department of Materials Science and Engineering, College of Engineering, Peking University, Beijing 100871 (China)


    The aim of this work was to investigate the effect of various sterilization methods on surface characteristics and biocompatibility of MgCa alloy, with pure Mg as a comparison, including steam autoclave sterilization (SA), ethylene oxide steam sterilization (EO), glutaraldehyde sterilization (GD), dry heat sterilization (DH) and Co60 γ ray radiation sterilization (R) technologies. The surface characterizations were performed by environmental scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, grazing incidence X-ray diffraction, water contact angle and surface free energy measurement, whereas the cytotoxicity and hemocompatibility were evaluated by cellular adhesive experiment, platelet adhesion and hemolysis test. The results showed that the five sterilization processes caused more changes on the surface of MgCa alloy than that on the surface of pure Mg. The GD sterilization caused the most obvious changes on the surface of the pure Mg, and the SA sterilization made the largest alteration on the MgCa alloy surface. The GD and DH sterilization processes could cause increases on surface free energy for both pure Mg and MgCa alloys, while the other three sterilization processes reduced the surface free energy. The DH and GD sterilization processes caused the least alteration on the cell adhesion on pure Mg surface, whereas the EO sterilization performed the greatest impact on the cell adhesion on the Mg–Ca alloy surface. The hemolysis percentage of pure Mg and MgCa alloys were reduced by SA sterilization, meanwhile the other four sterilization processes increased their hemolysis percentages significantly, especially for the EO sterilization. - Highlights: • The effect of sterilization on surface chemistry and biocompatibility was studied. • Sterilization caused more surface changes on MgCa alloy than pure Mg. • Co60 γ ray radiation is the most appropriate sterilization process.

  2. Laser multi-layer cladding of Mg-based alloys

    陈长军; 王东生; 王茂才


    By laser multi-layer cladding using a pulsed Nd-YAG irradiation the thickness of the cladding zone Mg-based alloys(ZM2 and ZM5) can reach about 1. 0 mm. The microstructure of the substrate and the cladding zone wasstudied using optical microscope, scanning electron microscopy(SEM), X-ray diffractometry(XRD) and micro hard-ness analysis. It is observed that constituent of ZM5 alloy is δ+Mg17 Al12, that of ZM2 alloy is α+MgZn+Mg9Ce.That of cladding layer ZM2 alloy(L-ZM2) is Mg+ Mg2 Zn11 +MgCe; while that of the cladding layer ZM5 alloy(L-ZM5) is Mg+Mg32 (Al, Zn)49. The hardness of the cladding area can be increased to values above HV127. Veryfine uniform microstructure and the produced new phases of nanometer/sub-micrometer order were obtained. Now,many repaired Mg-based alloy components have been passed by flying test in outside field.

  3. Adsorption of arginine, glycine and aspartic acid on Mg and Mg-based alloy surfaces: A first-principles study

    Fang, Zhe; Wang, Jianfeng; Yang, Xiaofan; Sun, Qiang; Jia, Yu; Liu, Hairong; Xi, Tingfei; Guan, Shaokang


    Studying the adsorption behaviors of biomolecules on the surface of Mg and Mg-based alloy has a fundamental and important role for related applications in biotechnology. In the present work, we systematically investigate and compare the adsorption properties of three typical amino acids, i.e., Arg (arginine), Gly (glycine) and Asp (aspartic acid), which form RGD tripeptide, on the Mg (0 0 0 1) surface with various doping (Zn, Y, and Nd), and aim to realize proper binding between biomolecules and Mg and Mg-based biomedical materials. Our results show that flat adsorption configurations of the functional groups binding to the surfaces are favored in energy for all the three selected amino acids. In specific, for the amino acids adsorped on clean Mg (0 0 0 1) surface, the adsorption energy (Eads) of Arg is found to be -1.67 eV for the most stable configuration, with amino and guanidyl groups binding with the surface. However, Gly (Asp) is found to binding with the surface through amino and carboxyl groups, with a -1.16 eV (-1.15 eV) binding energy. On the 2% Zn doped Mg (0 0 0 1) alloy surface (Mg-Zn (2%)), the Eads are significantly increased to be -1.91 eV, -1.32 eV and -1.35 eV for Arg, Gly and Asp, respectively. While the Mg-Y (1%) and Mg-Nd (1%) slightly weaken the adsorption of three amino acids. Moreover, we have performed detail discussions of the binding properties between amino acids and surfaces by projected density of states (PDOS) combined with charge transfer analyses. Our studies provide a comprehensive understanding on the interactions between amino acids and Mg and Mg-based alloy surfaces, with respect to facilitate the applications of Mg and Mg-based biomedical alloys in biosensing, drug delivery, biomolecule coating and other fields in biotechnology.

  4. Microstructure, In Vitro Corrosion Behavior and Cytotoxicity of Biodegradable Mg-Ca-Zn and Mg-Ca-Zn-Bi Alloys

    Bakhsheshi-Rad, H. R.; Hamzah, E.; Tok, H. Y.; Kasiri-Asgarani, M.; Jabbarzare, S.; Medraj, M.


    The effects of bismuth (Bi) addition on the microstructure and corrosion behavior of the Mg-Ca-Zn-Bi alloys were evaluated using electron microscopy, electrochemical test and electrochemical impedance spectroscopy. Microstructural observations showed that Mg-1.2Ca-1Zn- xBi ( x = 0.5, 1.5, 3 wt.%) are composed of Mg2Ca, Ca2Mg6Zn3 and Mg3Bi2 phases while a new phase Mg2Bi2Ca appeared after the addition of 5 and 12 wt.% Bi to the Mg-1.2Ca-1Zn alloy. Furthermore, the additions of 0.5 wt.% Bi to the Mg-1.2Ca-1Zn alloy slightly improved the corrosion behavior of the alloy, while further increase in Bi amount from 1.5 to 12 wt.% has a deleterious effect on the corrosion behavior of the ternary Mg-1.2Ca-1Zn alloy which is driven by galvanic coupling effect. Cytotoxicity tests indicate that the Mg-1.2Ca-1Zn presents higher cell viability compared to Mg-1.2Ca-1Zn-0.5Bi alloy. In addition, the cell viability of both alloys increased with increasing incubation time while diluting the extracts to 50% and 10% improved the cell viabilities. The present results suggest that the Mg-1.2Ca-1Zn-0.5Bi can be interesting candidate for the development of degradable biomaterials and it is worthwhile for further investigation in an in vivo environment.

  5. Mechanical Properties of Mg-Gd and Mg-Y Solid Solutions

    Kula, Anna; Jia, Xiaohui; Mishra, Raj K.; Niewczas, Marek


    The mechanical properties of Mg-Gd and Mg-Y solid solutions have been studied under uniaxial tension and compression between 4 K and 298 K (-269 °C and 25 °C). The results reveal that Mg-Gd alloys exhibit higher strength and ductility under tension and compression attributed to the more effective solid solution strengthening and grain-boundary strengthening effects. Profuse twinning has been observed under compression, resulting in a material texture with strong dominance of basal component parallel to compression axis. Under tension, twining is less active and the texture evolution is controlled mostly by slip. The alloys exhibit pronounced yield stress asymmetry and significantly different work-hardening behavior under tension and compression. Increasing of Gd and/or Y concentration leads to the reduction of the tension-compression asymmetry due to the weakening of the recrystallization texture and more balanced twinning and slip activity during plastic deformation. The results suggest that under compression of Mg-Y alloys slip is more active than twinning in comparison to Mg-Gd alloys.

  6. Enhanced voltage-controlled magnetic anisotropy in magnetic tunnel junctions with an MgO/PZT/MgO tunnel barrier

    Chien, Diana; Li, Xiang; Wong, Kin; Zurbuchen, Mark A.; Robbennolt, Shauna; Yu, Guoqiang; Tolbert, Sarah; Kioussis, Nicholas; Khalili Amiri, Pedram; Wang, Kang L.; Chang, Jane P.


    Compared with current-controlled magnetization switching in a perpendicular magnetic tunnel junction (MTJ), electric field- or voltage-induced magnetization switching reduces the writing energy of the memory cell, which also results in increased memory density. In this work, an ultra-thin PZT film with high dielectric constant was integrated into the tunneling oxide layer to enhance the voltage-controlled magnetic anisotropy (VCMA) effect. The growth of MTJ stacks with an MgO/PZT/MgO tunnel barrier was performed using a combination of sputtering and atomic layer deposition techniques. The fabricated MTJs with the MgO/PZT/MgO barrier demonstrate a VCMA coefficient, which is ˜40% higher (19.8 ± 1.3 fJ/V m) than the control sample MTJs with an MgO barrier (14.3 ± 2.7 fJ/V m). The MTJs with the MgO/PZT/MgO barrier also possess a sizeable tunneling magnetoresistance (TMR) of more than 50% at room temperature, comparable to the control MTJs with an MgO barrier. The TMR and enhanced VCMA effect demonstrated simultaneously in this work make the MgO/PZT/MgO barrier-based MTJs potential candidates for future voltage-controlled, ultralow-power, and high-density magnetic random access memory devices.

  7. Comparing the Electrochemical Performance of LiFePO4/C Modified by Mg Doping and MgO Coating

    Jianjun Song


    Full Text Available Supervalent cation doping and metal oxide coating are the most efficacious and popular methods to optimize the property of LiFePO4 lithium battery material. Mg-doped and MgO-coated LiFePO4/C were synthesized to analyze their individual influence on the electrochemical performance of active material. The specific capacity and rate capability of LiFePO4/C are improved by both MgO coating and Mg doping, especially the Mg-doped sample—Li0.985Mg0.015FePO4/C, whose discharge capacity is up to 163 mAh g−1, 145.5 mAh g−1, 128.3 mAh g−1, and 103.7 mAh g−1 at 1 C, 2 C, 5 C, and 10 C, respectively. The cyclic life of electrode is obviously increased by MgO surface modification, and the discharge capacity retention rate of sample LiFePO4/C-MgO2.5 is up to 104.2% after 100 cycles. Comparing samples modified by these two methods, Mg doping is more prominent on prompting the capacity and rate capability of LiFePO4, while MgO coating is superior in terms of improving cyclic performance.

  8. Effect of the partial substitution of Mg by Al on the crystal structure and hydrogenation behavior of La2Mg17

    ZHANG Qing'an; WANG Changchun; SI Tingzhi


    The effect of the partial substitution of Mg by Al on the crystal structure of La2Mg17 has been investigated. It was found that the La2Mg17 phase disappears after the partial substitution of Mg by Al. The La2(Mg0.9Al0.1)17 alloy contains La(Mg,Al)12 and La(Mg,Al)2. Further increasing the Al content, the La2(Mg0.8Al0.2)17 alloy consists of La(Mg,Al)12, La(Mg,Al)2, and Mg. The La(Mg0.93Al0.07)12 phase in the La2(Mg0.9Al0.1)17 alloy crystallizes with the ThMn12-type structure in space group I4/mmm (No.139). The lattice parameters were determined to be a = 1.03246(7) nm and c = 0.59410(6) nm. In the ThMn12-type structure, Al atoms occupy 8f site but the Al content is limited. Moreover, the hydrogenation characteristics have also been compared. La2Mg17 decomposes into LaH3 and MgH2 under hydrogen, but the La(Mg0.93Al0.07)12 phase can be hydrogenated into LaH3, MgH2, and La3Al11 at 473 K.

  9. Effect of strontium on crystallization of Mg2Si phase in Al-Si-Mg casting alloys

    廖恒成; 丁毅; 孙国雄


    Optical microscope and SEM were used to observe the changes of the microstructure of Al-11.6%Si-0.4%Mg alloys with varying strontium additions and the effect of strontium on the crystallization of Mg2Si phase was discussed. It is found that Mg2Si phase nucleates on the surfaces of the eutectic silicon flakes in the unfully modified alloys, growing as meshwork or bamboo-shoot shape, however, very few and fine Mg2Si particles phase are isolated at the boundaries of the eutectic cells in the fully modified alloys. Strontium has an important influence on the crystallization of Mg2Si phase in Al-Si-Mg casting alloys and it is thought to be related to the increase of the amount of dendritic α phase and the modifying degree of eutectic silicon phase.

  10. Microstructure and properties of Mg-Al binary alloys

    ZHENG Wei-chao


    Full Text Available The effects of different amounts of added Al, ranging from 1 % to 9 %, on the microstructure and properties of Mg-Al binary alloys were investigated. The results showed that when the amount of added Al is less than 5%, the grain size of the Mg-Al binary alloys decreases dramatically from 3 097 μm to 151 μm with increasing addition of Al. Further addition of Al up to 9% makes the grain size decrease slowly to 111 μm. The α-Mg dendrite arms are also refined. Increasing the amount of added Al decreases the hot cracking susceptibility of the Mg-Al binary alloys remarkably, and enhances the micro-hardness of the α-Mg matrix.

  11. Microstructure and properties of Mg-Al binary alloys

    ZHENG Wei-chao; LI Shuang-shou; TANG Bin; ZENG Da-ben


    The effects of different amounts of added Al, ranging from 1% to 9%, on the microstructure and properties of Mg-Al binary alloys were investigated. The results showed that when the amount of added Al is less than 5%, the grain size of the Mg-Al binary alloys decreases dramatically from 3 097 μm to 151 μm with increasing addition of Al. Further addition of Al up to 9% makes the grain size decrease slowly to 111 μm. The α-Mg dendrite arms are also refined. Increasing the amount of added Al decreases the hot cracking susceptibility of the Mg-Al binary alloys remarkably, and enhances the micro-hardness of the α-Mg matrix.

  12. Formation of Mg2Ni with enhanced kinetics: Using MgH2 instead of Mg as a starting material

    Zhao, Bin; Fang, Fang; Sun, Dalin; Zhang, Qingan; Wei, Shiqiang; Cao, Fenglei; Sun, Huai; Ouyang, Liuzhang; Zhu, Min


    At a temperature over the decomposition point (375 °C) of MgH2, the formation of Mg2Ni is greatly enhanced from the 2MgH2+Ni system, as compared to the 2Mg+Ni system. In support of this finding, in-situ observation of X-ray absorption fine structure of the two systems indicates that MgNi bonds form faster in the 2MgH2+Ni system than in the 2Mg+Ni system. Furthermore, theoretical modeling also shows that Mg atoms are readily released from MgH2 using much less energy and thus are more available to react with Ni once the dehydrogenation of MgH2 occurs, as compared to normal Mg.

  13. Cardiovascular effect of dental anesthesia with articaine (40 mg with epinefrine 0,5 mg % and 40 mg with epinefrine 1 mg%) versus mepivacaine (30 mg and 20 mg with epinefrine 1 mg%) in medically compromised cardiac patients: a cross-over, randomized, single blinded study.

    Torres-Lagares, Daniel; Serrera-Figallo, María-Ángeles; Machuca-Portillo, Guillermo; Corcuera-Flores, José-Ramón; Machuca-Portillo, Carmen; Castillo-Oyagüe, Raquel; Gutiérrez-Pérez, José-Luis


    The aim of the present study is to compare cardiovascular safety profiles of two dental anesthetics: articaine versus two standard mepivacaine solutions used during etiological periodontal treatment in cardiovascular patients. Using a cross-over study design, ten cardiovascular patients were randomly assigned to dental treatment with 1.8 mL of a local anesthetic injected on each quadrant of the mouth: Articaine (40 mg with Epinephrine 0.5 mg % and 40 mg with Epinephrine 1mg %) or Mepivacaine (30 mg and 20 mg with Epinephrine 1mg %). A computer programme enabled continuous longitudinal data collection: O2 saturation, blood pressure (BP) and heart rate (HR). No severe clinical side effects were observed. During the treatment period, we observed statistically significant differences as regards HR between injections with and without adrenalin (p< 0.039) and as regards systolic (p< 0.046) and diastolic (p < 0.046) blood pressure during the stabilization period. In both cases, the parameters under study increase. Age, gender, jaw treated, treatment duration and the rest of cardiovascular variables did not affect the results. None of the patients underwent ischemic alterations or any other complication derived from the treatment or the anesthesia. According to the results of our study, dental anesthetics with standard concentrations of Epinephrine seem to alter HR and BP. Although no cardiac ischemic alterations or any other cardiovascular complications have been observed, we must be cautious with the administration of anesthetics containing vasoconstrictors in patients with cardiovascular diseases.

  14. Laser cladding of a Mg based Mg-Gd-Y-Zr alloy with Al-Si powders

    Chen, Erlei; Zhang, Kemin; Zou, Jianxin


    In the present work, a Mg based Mg-Gd-Y-Zr alloy was subjected to laser cladding with Al-Si powders at different laser scanning speeds in order to improve its surface properties. It is observed that the laser clad layer mainly contains Mg2Si, Mg17Al12 and Al2(Gd,Y) phases distributed in the Mg matrix. The depth of the laser clad layer increases with decreasing the scanning speed. The clad layer has graded microstructures and compositions. Both the volume fraction and size of Mg2Si, Mg17Al12 and Al2(Gd,Y) phases decreases with the increasing depth. Due to the formation of these hardening phases, the hardness of clad layer reached a maximum value of HV440 when the laser scanning speed is 2 mm/s, more than 5 times of the substrate (HV75). Besides, the corrosion properties of the untreated and laser treated samples were all measured in a NaCl (3.5 wt.%) aqueous solution. The corrosion potential was increased from -1.77 V for the untreated alloy to -1.13 V for the laser clad alloy with scanning rate of 2 mm/s, while the corrosion current density was reduced from 2.10 × 10-5 A cm-2 to 1.64 × 10-6 A cm-2. The results show that laser cladding is an efficient method to improve surface properties of Mg-Rare earth alloys.

  15. Thermodynamic modeling of the La-Mg-Y system and Mg-based alloys database

    DU Zhenmin; GUO Cuiping; LI Changrong; ZHANG Weijing


    As an example of the La-Mg-Y system, the method how to set up the thermodynamic model of individual phases was introduced in the process of thermodynamic optimization. The solution phases (liquid, body-centered cubic,face-centered cubic, hexagonal close-packed and double hexagonal close-packed) were modeled with the Redlich-Kister equation. The compound energy model has been used to describe the thermodynamic functions of the intermetallic compounds in the La-Mg-Y systems. The compounds Mg2Y, Mg24Y5, Mg12La, Mg17La2, Mg41La5, Mg3La and Mg2La in the La-Mg-Y system were treated as the formulae (Mg, Y)2(La,Mg, Y), Mg24(La,Mg, Y)4Y, Mg12(La, Y), Mg17(La, Y)2,Mg41(La,Y)5, Mg3(La,Mg,Y) and Mg2(La,Y), respectively. A model (La,Mg,Y)0.5(La,Mg,Y)0.5 was applied to describe the compound MgM formed by MgLa and MgY in order to cope with the order-disorder transition between body-centered cubic solution (A2) and MgM with CsCl-type structure (B2) in the La-Mg-Y system. The Gibbs energies of individual phases were optimized in the La-Mg, La-Y and La-Mg-Y systems by CALPHAD technique. The projection of the liquidus surfaces for the La-Mg-Y system was predicted. The Mg-based alloys database including 36 binary and 15 ternary systems formed by Mg, Al, Cu, Ni, Mn, Zn and rare earth elements was set up in SGTE standard.

  16. Combustion and sensitivity characteristics of Mg/TF pyrolants

    Kuwahara, T.; Matsuo, S.; Shinozaki, N. [Aerospace Division, Nissan Motor Co Ltd, Saitama (Japan)


    Burning rate and sensitivity characteristics of energetic mixtures composed of metal particles and oxidizers, the so called `pyrolants`, were studied experimentally. The pyrolants tested were made of various particle sizes of magnesium (Mg) and poly-tetrafluoroethylene (TF). Mg/TF pyrolant produces high combustion flame temperature, so it is used as heat sources and igniter pyrolants. The maximum flame temperature (Tf) of Mg/TF pyrolant is 3271 K at 0.1 MPa, and 3483 K at 1 MPa. These values are obtained when Mg concentration is 30 %. When the Mg concentrations are less than 50 %, the pyrolants are not able to burn stably at one atmosphere. The burning rate increases with increasing concentration of Mg and decreases with increasing the mean diameter of Mg particles at constant pressure. Sensitivity characteristics were evaluated with drop hammer test and the weight used was 5 kg. Explosive energy decreased with increasing burning rate, so there is strong relationship between burning rate and explosive energy. (authors) 8 refs.

  17. Effects of Mg content on pore structure and electrochemical corrosion behaviors of porous Al-Mg alloys

    何文远; 肖逸锋; 吴靓; 许艳飞; 钱锦文; 贺跃辉; 郑学军


    Porous Al-Mg alloys with different nominal compositions were successfully fabricated via elemental powder reactive synthesis, and the phase composition, pore structure, and corrosion resistance were characterized with X-ray diffractometer, scanning electron microscope and electrochemical analyzer. The volume expansion ratio, open porosity and corrosion resistance in 3.5% (mass fraction) NaCl aqueous solution of the alloys increase at first and then decrease with the increase of Mg content. The maxima of volume expansion ratio and open porosity are 18.3% and 28.1% for the porous Al-56%Mg (mass fraction) alloy, while there is the best corrosion resistance for the porous Al-37.5% Mg (mass fraction) alloy. The pore formation mechanism can be explained by Kirkendall effect, and the corrosion resistance can be mainly affected by the phase composition for the porous Al-Mg alloys. They would be of the potential application for filtration in the chloride environment.

  18. Mg-Zr-Sr alloys as biodegradable implant materials.

    Li, Yuncang; Wen, Cuie; Mushahary, Dolly; Sravanthi, Ragamouni; Harishankar, Nemani; Pande, Gopal; Hodgson, Peter


    Novel Mg-Zr-Sr alloys have recently been developed for use as biodegradable implant materials. The Mg-Zr-Sr alloys were prepared by diluting Mg-Zr and Mg-Sr master alloys with pure Mg. The impact of Zr and Sr on the mechanical and biological properties has been thoroughly examined. The microstructures and mechanical properties of the alloys were characterized using optical microscopy, X-ray diffraction and compressive tests. The corrosion resistance was evaluated by electrochemical analysis and hydrogen evolution measurement. The in vitro biocompatibility was assessed using osteoblast-like SaOS2 cells and MTS and haemolysis tests. In vivo bone formation and biodegradability were studied in a rabbit model. The results indicated that both Zr and Sr are excellent candidates for Mg alloying elements in manufacturing biodegradable Mg alloy implants. Zr addition refined the grain size, improved the ductility, smoothed the grain boundaries and enhanced the corrosion resistance of Mg alloys. Sr addition led to an increase in compressive strength, better in vitro biocompatibility, and significantly higher bone formation in vivo. This study demonstrated that Mg-xZr-ySr alloys with x and y ≤5 wt.% would make excellent biodegradable implant materials for load-bearing applications. Copyright © 2012 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  19. Aliskiren attenuates steatohepatitis and increases turnover of hepatic fat in mice fed with a methionine and choline deficient diet.

    Kuei-Chuan Lee

    Full Text Available BACKGROUND & AIMS: Activation of the renin-angiotensin-system is known to play a role in nonalcoholic steatohepatitis. Renin knockout mice manifest decreased hepatic steatosis. Aliskiren is the first direct renin inhibitor to be approved for clinical use. Our study aims to evaluate the possible therapeutic effects and mechanism of the chronic administration of aliskiren in a dietary steatohepatitis murine model. METHODS: Male C57BL/6 mice were fed with a methionine and choline-deficient (MCD diet to induce steatohepatitis. After 8 weeks of feeding, the injured mice were randomly assigned to receive aliskiren (50 mg·kg(-1 per day or vehicle administration for 4 weeks. Normal controls were also administered aliskiren (50 mg·kg(-1 per day or a vehicle for 4 weeks. RESULTS: In the MCD mice, aliskiren attenuated hepatic steatosis, inflammation and fibrosis. Aliskiren did not change expression of lipogenic genes but increase turnover of hepatic fat by up-regulating peroxisome proliferator-activated receptor α, carnitine palmitoyltransferase 1a, cytochrome P450-4A14 and phosphorylated AMP-activated protein kinase. Furthermore, aliskiren decreased the hepatic expression of angiotensin II and nuclear factor κB. The levels of oxidative stress, hepatocyte apoptosis, activation of Kupffer cells and hepatic stellate cells, and pro-fibrotic markers were also reduced in the livers of the MCD mice receiving aliskiren. CONCLUSIONS: Aliskiren attenuates steatohepatitis and fibrosis in mice fed with a MCD diet. Thus, the noted therapeutic effects might come from not only the reduction of angiotensin II but also the up-regulation of fatty acid oxidation-related genes.

  20. Structures and stabilities of (MgO)n nanoclusters.

    Chen, Mingyang; Felmy, Andrew R; Dixon, David A


    Global minima for (MgO)n structures were optimized using a tree growth-hybrid genetic algorithm in conjunction with MNDO/MNDO/d semiempirical molecular orbital calculations followed by density functional theory geometry optimizations with the B3LYP functional. New lowest energy isomers were found for a number of (MgO)n clusters. The most stable isomers for (MgO)n (n > 3) are 3-dimensional. For n < 20, hexagonal tubular (MgO)n structures are more favored in energy than the cubic structures. The cubic structures and their variations dominate after n = 20. For the cubic isomers, increasing the size of the cluster in any dimension improves the stability. The effectiveness of increasing the size of the cluster in a specific dimension to improve stability diminishes as the size in that dimension increases. For cubic structures of the same size, the most compact cubic structure is expected to be the more stable cubic structure. The average Mg-O bond distance and coordination number both increase as n increases. The calculated average Mg-O bond distance is 2.055 Å at n = 40, slightly smaller than the bulk value of 2.104 Å. The average coordination number is predicted to be 4.6 for the lowest energy (MgO)40 as compared to the bulk value of 6. As n increases, the normalized clustering energy ΔE(n) for the (MgO)n increases and the slope of the ΔE(n) vs n curve decreases. The value of ΔE(40) is predicted to be 150 kcal/mol, as compared to the bulk value ΔE(∞) = 176 kcal/mol. The electronic properties of the clusters are presented and the reactive sites are predicted to be at the corners.

  1. Arecoline improves vascular endothelial function in high fructose-fed rats via increasing cystathionine-Ylyase expression and activating KATp channels

    Hong-yan LING; Guang WANG; Wei ZHANG; Xing LI; Shou-hong ZHOU; Bi HU


    Aim:To investigate the effect of arecoline,a major component of betel nut,on vascular endothelial function in high fructose-fed rats and the potential mechanisms underlying the effect.Methods:Male Wistar rats were fed a high-fructose or control diet for 16 weeks.At the beginning of week 13,the rats were injected ip with low (0.5 mg·kg 1·d-1),medi u m (1.0 mg·kg1·d-1) or high (5.0 mg·kg 1·d 1) doses of arecoline for 4 weeks.At the termination of the treatments,blood was collected,fasting blood glucose (FBG) and serum insulin (FSI) levels were measured,and insulin sensitivity index (ISI) was calculated.The thoracic aortas were isolated and aortic rings were prepared for studying ACh-induced endothelium-dependent vasorelaxation (EDVR).The mRNA and protein expression of cystathionine-y-lyase (CSE) in the thoracic aortas was analyzed using RTPCR and Western blot analysis,respectively.Results:In high fructose-fed rats,the levels of FBG and FSI were remarkably increased,whereas the ISI and the mRNA and protein expression of CSE were significantly decreased.ACh-induced EDVR in the aortic rings from high fructose-fed rats was remarkably reduced.These changes were reversed by treatment with high dose arecoline.Pretreatment of the aortic rings rings from high fructose-fed rats with the CSE inhibitor propargylglycine (10 mmol/L) orthe ATP-sensitive potassium (KATP) channel blocker glibenclamide (10 mmol/L) abolished the restoration of ACh-induced EDVR by high dose arecoline.On the contrary,treatment with high dose arecoline significantly impaired ACh-induced EDVR in the aortic rings from control rats,and pretreatment with propargylglycine or glibenclamide did not cause further changes.Conclusion:Arecoline treatment improves ACh-induced EDVR in high fructose-fed rats,and the potential mechanism of action might be associated with increase of CSE expression and activation of KATP channels by arecoline.

  2. Arecoline improves vascular endothelial function in high fructose-fed rats via increasing cystathionine-γ-lyase expression and activating K(ATP) channels.

    Ling, Hong-yan; Wang, Guang; Zhang, Wei; Li, Xing; Zhou, Shou-hong; Hu, Bi


    To investigate the effect of arecoline, a major component of betel nut, on vascular endothelial function in high fructose-fed rats and the potential mechanisms underlying the effect. Male Wistar rats were fed a high-fructose or control diet for 16 weeks. At the beginning of week 13, the rats were injected ip with low (0.5 mg·kg(-1)·d(-1)), medium (1.0 mg·kg(-1)·d(-1)) or high (5.0 mg·kg(-1)·d(-1)) doses of arecoline for 4 weeks. At the termination of the treatments, blood was collected, fasting blood glucose (FBG) and serum insulin (FSI) levels were measured, and insulin sensitivity index (ISI) was calculated. The thoracic aortas were isolated and aortic rings were prepared for studying ACh-induced endothelium-dependent vasorelaxation (EDVR). The mRNA and protein expression of cystathionine-γ-lyase (CSE) in the thoracic aortas was analyzed using RT-PCR and Western blot analysis, respectively. In high fructose-fed rats, the levels of FBG and FSI were remarkably increased, whereas the ISI and the mRNA and protein expression of CSE were significantly decreased. ACh-induced EDVR in the aortic rings from high fructose-fed rats was remarkably reduced. These changes were reversed by treatment with high dose arecoline. Pretreatment of the aortic rings rings from high fructose-fed rats with the CSE inhibitor propargylglycine (10 mmol/L) or the ATP-sensitive potassium (K(ATP)) channel blocker glibenclamide (10 mmol/L) abolished the restoration of ACh-induced EDVR by high dose arecoline. On the contrary, treatment with high dose arecoline significantly impaired ACh-induced EDVR in the aortic rings from control rats, and pretreatment with propargylglycine or glibenclamide did not cause further changes. Arecoline treatment improves ACh-induced EDVR in high fructose-fed rats, and the potential mechanism of action might be associated with increase of CSE expression and activation of K(ATP) channels by arecoline.

  3. Effect of Mg content on microstructure and corrosion behavior of hot dipped Zn–Al–Mg coatings

    Yao, Caizhen; Lv, Haibing [Research Centre of Laser Fusion, CAEP, P.O.Box 919-988-5, Mianyang, Sichuan 621900 (China); Zhu, Tianping [Department of Chemical and Materials Engineering, The University of Auckland, PB 92019, Auckland 1142 (New Zealand); Zheng, Wanguo [Research Centre of Laser Fusion, CAEP, P.O.Box 919-988-5, Mianyang, Sichuan 621900 (China); Yuan, Xiaodong, E-mail: [Research Centre of Laser Fusion, CAEP, P.O.Box 919-988-5, Mianyang, Sichuan 621900 (China); Gao, Wei, E-mail: [Department of Chemical and Materials Engineering, The University of Auckland, PB 92019, Auckland 1142 (New Zealand)


    In this article, Zn–Al–Mg coatings were prepared by hot dipping method. The surface morphology, cross–section microstructure, microhardness, composition, corrosion behaviour of ZAM coatings were investigated by using X–ray diffraction (XRD), Optical microscope, Environmental scanning electron microscopy equipped with EDS (FESEM–EDS), Microhardness tester and Electrochemical analysis respectively. Corrosion test was also performed in a standard salt fog spray chamber. Microstructure studies indicates that Zn grain size was refined and eutectic areas at Zn grain boundary areas increased with increasing Mg content. ZA5M1.5 and ZA5M2 coatings have two distinct layers. Mg tends to exist in the outer layer while Al is in the inner layer. The inner layer is composed of Al{sub 5}Fe{sub 2}Zn{sub 0.4} intermetallic, which may to contribute to the microhardness. The outer layer is Zn grains surrounded by Zn–Mg etutectics, which may improve the corrosion resistance. The microhardness is more than 700 HV{sub 50g} for Al-rich layer and around 151 HV{sub 25g} for Mg-rich layer. The improved corrosion resistance of Zn–5%Al-1.5%Mg coating comes from the corrosion product of flocculent type simonkolleite, which prolongs the micro-path and impedes the movement of O{sub 2} and H{sub 2}O, ultimately retards the overall corrosion process. - Highlights: • Two-layer structured Zn–Al–Mg coatings were prepared by hot dipping method. • Mg exists in the outer layer while Al exists in the inner layer of Zn–Al–Mg coating. • Zn–Al–Mg coating has better protective ability than Zn and Zn–Al coatings. • The Mg-modified simonkolleite is the reason of the enhanced corrosion resistance.

  4. Growth of high Mg content wurtzite MgZnO epitaxial films via pulsed metal organic chemical vapor deposition

    Alema, Fikadu; Ledyaev, Oleg; Miller, Ross; Beletsky, Valeria; Osinsky, Andrei; Schoenfeld, Winston V.


    We report on the growth of high Mg content, high quality, wurtzite MgxZn1-xO (MgZnO) epitaxial films using a pulsed metal organic chemical vapor deposition (PMOCVD) method. Series of MgZnO films with variable Mg concentration were deposited on bare and AlN coated sapphire substrates. The band gap of the films estimated using UV-visible transmission spectra ranges from 3.24 eV to 4.49 eV, corresponding to fraction of Mg between x=0.0 and x=0.51, as determined by Rutherford backscattering spectroscopy. The cathodoluminescence (CL) measurement has shown a blue-shift in the peak position of MgZnO with an increasing Mg content. No multi-absorption edges and CL band splitting were observed, suggesting the absence of phase segregation in the as grown films. The crystal structure and phase purity of the films were also confirmed by XRD analysis. Hall effect measurement in van der Pauw configuration was employed to evaluate the electrical properties of the films. With a rise in Mg incorporation into the ZnO lattice, the films became very resistive, consistent with the widening of the band gap. The AFM measurement on the films has shown a decreasing surface roughness with an Mg content. To the best of our knowledge, the current result shows the highest Mg content (x=0.51), high quality, wurtzite MgZnO epitaxial film ever grown by MOCVD. The high Mg incorporation without phase separation is believed to be due to the non-equilibrium behavior of the PMOCVD in which the kinetic processes dominate the thermodynamic one.

  5. First-principles study on mechanical properties of LaMg3 and LaCuMg2

    王明辉; 潘荣凯; 李鹏博; 卞楠; 唐壁玉; 彭立明; 丁文江


    With the substitution of part Mg in LaMg3by Cu, the elastic constantsC11 andC12 increase whileC44 decreases, implying an enhanced Poisson effect and smaller resistance to (100) shear. Furthermore, the bulk modulusB increases, while the shear modulusG, elastic modulusE and anisotropic ratioA are reduced. The calculated Debye temperature of LaCuMg2 is lower, implying the weaker interaction between atoms in LaCuMg2. Then, the stress-strain curves in entire range and the ideal strength at critical strain are studied. The present results show that the lowest ideal tensile strength for LaMg3 and LaCuMg2is in the direction. The ideal shear strength on the (110) slip system of LaMg3 is greater than LaCuMg2. The density of states and charge density distribution are further studied to understand the inherent mechanism of the mechanical properties.

  6. Effect of Synthesized MgNi4Y Catalyst on Hydrogen Desorption Properties of Milled MgH2

    ChitsazKhoyi, Leila; Raygan, Shahram; Pourabdoli, Mehdi


    It has been reported that ball milling and adding catalyst can improve hydrogen desorption properties of MgH2. In this study, simultaneous effect of adding catalyst and ball milling on hydrogen desorption properties of MgH2 was studied. Mechanical alloying and heat treatment methods were used to synthesize MgNi4Y intermetallic as a catalyst. In this regard, pure Mg, Ni, and Y elemental powders were ball milled in different conditions and then heat treated at 1073 K (800 °C) for 4 hours. XRD and FESEM methods were used to investigate properties of the samples. It was found that, after 10 hours of ball milling and then heat treating at 1073 K (800 °C), MgNi4Y intermetallic was formed almost completely. The results of Sievert tests showed that as-received MgH2 did not release any significant amount of hydrogen at 623 K (350 °C). But, after ball milling for 10 hours, 0.8 wt pct hydrogen was released from MgH2 at 623 K (350 °C) in 40 minutes. Adding 10 wt pct catalyst via ball milling to MgH2 led to releasing 3.5 wt pct hydrogen in the same conditions. In addition, increasing ball milling time from 10 to 65 hours increased the amount of released hydrogen from 51 to 85 pct of theoretical hydrogen desorption value and improved kinetic of desorption process.

  7. The supplementation of low-P diets with microbial 6-phytase expressed in Aspergillus oryzae increases P and Ca digestibility in growing pigs.

    Torrallardona, D; Salvadó, R; Broz, J


    A trial was conducted to evaluate the dose response of a novel microbial 6-phytase expressed in Aspergillus oryzae (Ronozyme HiPhos; DSM Nutritional Products, Basel, Switzerland) in pigs. Forty-eight individually housed pigs (Landrace × Pietrain; 52 kg BW; 24 males and 24 females) were distributed among 6 experimental treatments consisting of a low-P diet (3.5 g P/kg; 1.1 g digestible P/kg), which was supplemented with 500, 1000, 2000, or 4000 units of phytase activity/kg, and a standard-P diet (4.5 g P/kg; 1.8 g digestible P/kg) that was supplemented with CaHPO(4). After 17 d, fresh feces were sampled from all pigs and the apparent total tract digestibility of DM, OM, ash, P, and Ca was measured using TiO(2) as indigestible marker. Blood samples were also obtained from each pig and serum was analyzed for P and Ca concentrations. The nonsupplemented low-P diet increased Ca and reduced P blood serum concentrations (P Phytase supplementation of the low-P diet reduced Ca (from 10.8 to 9.9 mg/dL; linear, P Phytase improved the total tract digestibility of P (from 29.0 to 62.3%; linear and quadratic, P phytase tested improves the apparent total tract digestibility of P in growing pigs and reduces P excretion in feces in a dose-dependent manner.

  8. Dexamethasone increases glucose cycling, but not glucose production, in healthy subjects

    Wajngot, A.; Khan, A.; Giacca, A.; Vranic, M.; Efendic, S. (Karolinska Hospital, Stockholm (Sweden))


    We established that measurement of glucose fluxes through glucose-6-phosphatase (G-6-Pase; hepatic total glucose output, HTGO), glucose cycling (GC), and glucose production (HGP), reveals early diabetogenic changes in liver metabolism. To elucidate the mechanism of the diabetogenic effect of glucocorticoids, we treated eight healthy subjects with oral dexamethasone (DEX; 15 mg over 48 h) and measured HTGO with (2-3H)glucose and HGP with (6-3H)glucose postabsorptively and during a 2-h glucose infusion (11.1 (2-3H)- minus (6-3H)glucose equals GC. DEX significantly increased plasma glucose, insulin, C peptide, and HTGO, while HGP was unchanged. In controls and DEX, glucose infusion suppressed HTGO (82 vs. 78%) and HGP (87 vs. 91%). DEX increased GC postabsorptively (three-fold) P less than 0.005 and during glucose infusion (P less than 0.05) but decreased metabolic clearance and glucose uptake (Rd), which eventually normalized, however. Because DEX increased HTGO (G-6-Pase) and not HGP (glycogenolysis + gluconeogenesis), we assume that DEX increases HTGO and GC in humans by activating G-6-Pase directly, rather than by expanding the glucose 6-phosphate pool. Hyperglycemia caused by peripheral effects of DEX can also contribute to an increase in GC by activating glucokinase. Therefore, measurement of glucose fluxes through G-6-Pase and GC revealed significant early effects of DEX on hepatic glucose metabolism, which are not yet reflected in HGP.

  9. Preparation and Hydrogen Storage Properties of Mg-Rich Mg-Ni Ultrafine Particles

    Jianxin Zou


    Full Text Available In the present work, Mg-rich Mg-Ni ultrafine powders were prepared through an arc plasma method. The phase components, microstructure, and hydrogen storage properties of the powders were carefully investigated. It is found that Mg2Ni and MgNi2 could be obtained directly from the vapor state reactions between Mg and Ni, depending on the local vapor content in the reaction chamber. A nanostructured MgH2 + Mg2NiH4 hydrogen storage composite could be generated after hydrogenation of the Mg-Ni ultrafine powders. After dehydrogenation, MgH2 and Mg2NiH4 decomposed into nanograined Mg and Mg2Ni, respectively. Thermogravimetry/differential scanning calorimetry (TG/DSC analyses showed that Mg2NiH4 phase may play a catalytic role in the dehydriding process of the hydrogenated Mg ultrafine particles.

  10. Mg(BH4)2和MgH2对RDX热分解特性的影响%Effect of Mg(BH4) 2 and MgH2 on Thermal Decomposition Performance of RDX

    姚淼; 陈利平; 堵平; 彭金华


    在黑索今(RDX)中加入具有高热值的金属氢化物(Mg(BH4)2和MgH2)有望提高RDX的爆炸性能,但同时给RDX的安全使用带来挑战.为了探索RDX与这2种金属氢化物的相容性与安定性,采用差示扫描量热法(DSC)研究Mg(BH4)2和MgH2对RDX热分解性能的影响,并由DSC得到的数据计算动力学参数,参照GJB770B——2005的方法分析这2种金属氢化物与RDX的相容性和安定性.结果表明,加入Mg(BH4)2使RDX的表观活化能从159.22 kJ/mol增加至180.27 kJ/mol,加入MgH2使RDX的表观活化能降低至133.69 kJ/mol; Mg(BH4)2与RDX的相容性为1级,MgH2与RDX的相容性为3级,加入Mg(BH4)2使RDX的安定性有所提高,加入MgH2降低了RDX的安定性.因此,在将MgH2作为RDX的高能添加剂以前,必须首先提高其与RDX的相容性以保证试验和存储过程的安全.%Metal hydrides ( Mg ( BH4) 2 and MgH2 ) with high heat values are expected to improve the explosion properties of RDX. However, they bring safety problems at the same time. In order to explore the consistencies between RDX and these two kinds of metal hydrides, the DSC was used to study the thermal decomposition characteristics of RDX influenced by the addition of Mg( BH4) 2 and MgH2. The consistencies between RDX and two kinds of metal hydrides were calculated and compared though the standard GJB770B - 2005 respectively. In addition, the stabilities of the mixtures were obtained, too. The results show that the addition of Mg(BH4)2 increases the apparent activation energy from 159. 22 kj/mol to 182.27 kj/mol and the addition of MgH2 decreases the apparent activation energy of RDX to 133. 69 kj/mol. The consistency grade of Mg( BH4 )2/RDX is 1 and the consistency grade of MgH2/RDX is 3 besides, the addition of Mg(BH4)2 is benefit to the stability of RDX and the addition of MgH2 lower the stability of RDX. So, how to enhance the consistency between RDX and MgH2 is the principal problem when adding MgH2 to RDX.


    郭冬丽; 宁佩芳; 袁媛


    Objective: To study the dynamic change and its diagnostic significance of MG7 expression in the process of gastric cancer development. Methods: The expression level of antigen MG7 was determined by immunohistochemistry method in 406 cases of gastric mucosa. The classification of intestinal metaplasia of gastric mucosa was determined by histochemistry method in 82 cases. Results: The positive rate of MG7 expression in normal gastric mucosa, intestinal metaplasia and dysplasia of gastric mucosa and gastric cancer were increased gradually (P<0.01). The positive rate of MG7 expression in superficial gastritis, atrophic gastritis and gastric cancer were increased on sequence (P<0.01). The positive rate of antigen MG7 expression in type Ⅲ intestinal metaplasia of gastric mucosa had significant difference,compared with that in type Ⅰ an Ⅱ intestinal metaplasia (P<0.05). Conclusion: MG7 antigen had close relationship with gastric cancer. Type Ⅲ intestinal metaplasia, atrophic gastritis and dysplasia should be followed up in order to improve the early detection of gastric cancer. MG7 antigen had great clinical value in the dynamic follow-up of gastric precursors.

  12. Highly (100) oriented MgO growth on thin Mg layer in MTJ structure

    Jimbo, K [Department of Physical Electronics, Tokyo Institute of Technology, 2-12-1-S3-42 O-okayama, Meguro, Tokyo 152-8552 (Japan); Nakagawa, S, E-mail:


    In order to apply Stress Assisted Magnetization Reversal (SAMR) method to perpendicular magnetoresistive random access memory (p-MRAM) with magnetic tunnel junction (MTJ) using MgO (001) oriented barrier layer, multilayer of Ta/ Terfenol-D/ Mg/ MgO and Ta/ Terfenol-D/ MgO were prepared. While the MgO layer, deposited directly on the Terfenol-D layer, did not show (100) orientatin, very thin metallic Mg layer, deposited prior to the MgO deposition, was effective to attain MgO (100) orientation. The crystalline orientation was very weak without Mg, however, the multilayer with Mg showed very strong MgO(100) peak and the MgO orientation was shifted depending on the Mg thickness.

  13. Biochar addition to an arsenic contaminated soil increases arsenic concentrations in the pore water but reduces uptake to tomato plants (Solanum lycopersicum L.).

    Beesley, Luke; Marmiroli, Marta; Pagano, Luca; Pigoni, Veronica; Fellet, Guido; Fresno, Teresa; Vamerali, Teofilo; Bandiera, Marianna; Marmiroli, Nelson


    Arsenic (As) concentrations in soil, soil pore water and plant tissues were evaluated in a pot experiment following the transplantation of tomato (Solanum lycopersicum L.) plantlets to a heavily As contaminated mine soil (~6000 mg kg(-1) pseudo-total As) receiving an orchard prune residue biochar amendment, with and without NPK fertiliser. An in-vitro test was also performed to establish if tomato seeds were able to germinate in various proportions of biochar added to nutrient solution (MS). Biochar significantly increased arsenic concentrations in pore water (500 μg L(-1)-2000 μg L(-1)) whilst root and shoot concentrations were significantly reduced compared to the control without biochar. Fruit As concentrations were very low (soil, but uptake to plant was reduced, and toxicity-transfer risk was negligible. Therefore leaching rather than food chain transfer appears the most probable immediate consequence of biochar addition to As contaminated soils.

  14. Two Proton Knockout from ^32Mg

    Fallon, P.; Rodriguez-Vieitez, E.; Macchiavelli, A. O.; Clark, R. M.; Lee, I.-Y.; Wiedeking, M.; Gade, A.; Adrich, P.; Bazin, D.; Bowen, M.; Campbell, C. M.; Cook, J. M.; Dinca, D. C.; Glasmacher, T.; McDaniel, S.; Mueller, W. F.; Ratiewicz, A. F.; Siwek, K.; Terry, J. R.; Wiesshaar, D.; Yoneda, K.; Brown, B. A.; Otsuka, T.; Tostevin, J. A.; Utsuno, Y.


    We present data and calculations on the near-dripline nucleus ^30Ne. Gamma-ray decays from excited states as well as inclusive and exclusive cross-sections were measured in the ^9Be(^32Mg,^30Ne γ)X two-proton knockout reaction at incident beam energies of 99.7 and 86.7 MeV/A. The measured inclusive cross section sigma = 0.22(4)mb is suppressed compared to calculation and is indicative of a reduced overlap of initial and final state wavefunctions. We interpret this reduction as a result of large 4p4h intruder components present in ^30Ne, but not ^32Mg. Large 4p4h amplitudes are predicted to generate increased T=1 paring strengths and to help stabilize the heavier fluorine isotopes against neutron decay. A new gamma-ray transition at 1443 keV is assigned to the decay of the 4^+ state based on the spin dependent sigma for 2 proton knockout from the (d5/2)^4 configuration.

  15. Maternal endotoxemia results in increases in blood pressure and body weight in rats

    WEI Yan-ling; LI Xiao-hui


    Objective To investigate the effects of prenatal exposure to lipopolysaccharide (LPS) on blood pressure and body weight of offspring in rats. Methods Sixteen healthy pregnant rats were randomly divided into two groups. The rats in LPS group were injected intraperitoneally with LPS (0.79 mg·kg-1) at the 8th, 10th, 12th day of gestation. Those in the control group were only treated with NS. After delivery, all offspring were weighed and blood pressure was measured by tail-cuff method once every two weeks from the 6th to 24th week. In the 15th week, their food intakes were weighed every day. At the end of the 24th week, the rats were put to death by decapitation. Abdominal adipose tissues were taken to weigh, and serum level of leptin was detected by RIA. Results The offspring with prenatal LPS exposure showed increased systemic arterial pressure, heavier body weight, elevated food intake, increased adipose tissue weight and increased circulating leptin compared with controls. Conclusions Prenatal exposure to LPS leads to increases in blood pressure and body weight in rats.

  16. Improved Hydrogen Storage Properties of Mg(BH4)2-Mg(AlH4)2 Combined Systems

    Xiao, Haoyuan; Leng, Haiyan; Yu, Zhigang; Li, Qian; Chou, Kuo-Chih

    Magnesium borohydride and Magnesium alanate were synthesized by mechanochemical metathesis reaction. The thermal decomposition behaviors of Mg(BH4)2-nMg(AlH4)2(n=0.5,1) systems were investigated as potential hydrogen storage materials. The results showed that the systems started to desorb H2 at 120 °C and desorbed 3.9 wt.% and 4.9 wt.% H2 below 300 °C when n equals 0.5 and 1, respectively, while individual Mg(BH4)2 started to desorb H2 at 250 °C and desorbed only 0.82 wt.% H2. Because of the exist of the Mg(AlH4)2, the isothermal desorption kinetics of Mg(BH4)2 in the Mg(BH4)2-0.5Mg(AlH4)2 systems was 50% faster than that of pristine Mg(BH4)2. In addition, the re-hydrogenation rates also increased 49.4% and 37.9%.

  17. Microstructures and mechanical properties of Al-Mg and Al-Zn-Mg based alloys containing minor scandium and zirconium

    尹志民; 姜锋; 潘青林; 郭飞跃; 朱大鹏; 宋练鹏; 曾渝; 王涛


    A series of Al-Mg and Al-Zn-Mg based alloys with and without Sc, Zr were prepared by ingot metallurgy. The mechanical properties and microstructures of the studied alloys under different treatment conditions were studied. In addition, the existing form and acting mechanism of minor Sc and Zr in Al-Mg and Al-Zn-Mg based alloys were analyzed and discussed. The following conclusions can be drawn. First, adding of minor Sc and Zr to those alloys can increase the strength of Al-Mg and Al-Zn-Mg based alloys by 25%, while the ductility can remain in 15% and 8%, respectively. Second, in Al-Mg and Al-Zn-Mg based alloys, minor Sc and Zr mainly exist in two forms of aluminides containing Sc and Zr, one is Al3(Sc,Zr)I precipitated from the melt during solidification, the other is Al3(Sc,Zr)Ⅱ precipitated during homogenization. The former is the most effective grain refiner for α(Al) solid solution matrix, and the latter is coherent with the matrix and can strongly pin dislocations and subboundaries, which can effectively restrain recrystallization of the alloys during hot deformation, annealing and solid solution. Third, strengthening caused by adding minor Sc and Zr to the studied alloys is mainly due to fine-grain strengthening, precipitation strengthening and substructure strengthening of Al3(Sc, Zr) caused by restraining recrystallization.

  18. Simulating GTP:Mg and GDP:Mg with a simple force field: a structural and thermodynamic analysis.

    Simonson, Thomas; Satpati, Priyadarshi


    Di- and tri-phosphate nucleotides are essential cofactors for many proteins, usually in an Mg(2+) -bound form. Proteins like GTPases often detect the difference between NDP and NTP and respond by changing conformations. To study such complexes, simple, fixed charge force fields have been used, which allow long simulations and precise free energy calculations. The preference for NTP or NDP binding depends on many factors, including ligand structure and Mg(2+) coordination and the changes they undergo upon binding. Here, we use a simple force field to examine two Mg(2+) coordination modes for the unbound GDP and GTP: direct, or "Inner Sphere" (IS) coordination by one or more phosphate oxygens and indirect, "Outer Sphere" (OS) coordination involving one or more bridging waters. We compare GTP: and GDP:Mg binding with OS and IS coordination; combining the results with experimental data then indicates that GTP prefers the latter. We also examine different kinds of IS coordination and their sensitivity to a key force field parameter: the optimal Mg:oxygen van der Waals distance Rmin . Increasing Rmin improves the Mg:oxygen distances, the GTP: and GDP:Mg binding affinities, and the fraction of GTP:Mg with β + γ phosphate coordination, but does not improve or change the GTP/GDP affinity difference, which remains much larger than experiment. It has no effect on the free energy of GDP binding to a GTPase. Copyright © 2012 Wiley Periodicals, Inc.

  19. Secondary ageing in an Al-Cu-Mg alloy with high Cu/Mg ratio

    Dupasquier, A.; Folegati, P. [Politecnico di Milano (Italy). Ist. di Fisica della Materia; Ferragut, R. [Politecnico di Milano (Italy). Ist. di Fisica della Materia; IFIMAT, Univ. Nacional del Centro de la Provincia de Buenos Aires and CICPBA, Tandil (Argentina); Massazza, M.; Riontino, G. [Ist. Nazionale di Fisica della Materia, Dipt. di Chimica I.F.M., Univ. di Torino (Italy); Somoza, A. [IFIMAT, Univ. Nacional del Centro de la Provincia de Buenos Aires and CICPBA, Tandil (Argentina)


    The mechanisms governing secondary ageing (structural transformations occurring at low temperature after a heat treatment at higher temperature) were investigated by combined measurements of positron lifetimes, Vickers microhardness measurements and differential scanning calorimetry (DSC) on a laboratory alloy (Al-4.5 wt.% Cu-0.56 wt.% Mg). The results show that hardening occurs at a much slower rate than in case of primary ageing at RT. The positron lifetime data suggest that the hardening rate is controlled by slow release of vacancies from Cu-rich clusters formed during the initial high temperature treatment. The hardening stage is concomitant with an increase of the positron lifetime, and has probably the same origin, which is the formation of solute clusters containing vacancies and Mg as essential components. The formation at low temperature of new structures is also demonstrated by DSC. (orig.)

  20. IL‐6 Regulates Extracellular Matrix Remodeling Associated With Aortic Dilation in a Fibrillin‐1 Hypomorphic mgR/mgR Mouse Model of Severe Marfan Syndrome

    Ju, Xiaoxi; Ijaz, Talha; Sun, Hong; LeJeune, Wanda; Vargas, Gracie; Shilagard, Tuya; Recinos, Adrian; Milewicz, Dianna M.; Brasier, Allan R.; Tilton, Ronald G.


    Background Development of thoracic aortic aneurysms is the most significant clinical phenotype in patients with Marfan syndrome. An inflammatory response has been described in advanced stages of the disease. Because the hallmark of vascular inflammation is local interleukin‐6 (IL‐6) secretion, we explored the role of this proinflammatory cytokine in the formation of aortic aneurysms and rupture in hypomorphic fibrillin‐deficient mice (mgR/mgR). Methods and Results MgR/mgR mice developed ascending aortic aneurysms with significant dilation of the ascending aorta by 12 weeks (2.7±0.1 and 1.3±0.1 for mgR/mgR versus wild‐type mice, respectively; P<0.001). IL‐6 signaling was increased in mgR/mgR aortas measured by increases in IL‐6 and SOCS3 mRNA transcripts (P<0.05) and in cytokine secretion of IL‐6, MCP‐1, and GM‐CSF (P<0.05). To investigate the role of IL‐6 signaling, we generated mgR homozygous mice with IL‐6 deficiency (DKO). The extracellular matrix of mgR/mgR mice showed significant disruption of elastin and the presence of dysregulated collagen deposition in the medial‐adventitial border by second harmonic generation multiphoton autofluorescence microscopy. DKO mice exhibited less elastin and collagen degeneration than mgR/mgR mice, which was associated with decreased activity of matrix metalloproteinase‐9 and had significantly reduced aortic dilation (1.0±0.1 versus 1.6±0.2 mm change from baseline, DKO versus mgR/mgR, P<0.05) that did not affect rupture and survival. Conclusion Activation of IL‐6‐STAT3 signaling contributes to aneurysmal dilation in mgR/mgR mice through increased MMP‐9 activity, aggravating extracellular matrix degradation. PMID:24449804

  1. Fabrication and superconducting properties of internal Mg diffusion processed MgB2 wires using MgB4 precursors

    Xu, Da; Wang, Dongliang; Yao, Chao; Zhang, Xianping; Ma, Yanwei; Oguro, Hidetoshi; Awaji, Satoshi; Watanabe, Kazuo


    Monofilament MgB2/Nb/Monel wires were fabricated using three different MgB4 precursors by an internal Mg diffusion (IMD) process. The wire geometry and heat-treatment conditions were optimized in order to improve the critical current density (J c) of the MgB2 wire. The influences of the quality of MgB4 powders, such as the particle size and MgO impurity, on the microstructure and superconducting properties of the wires were discussed. Although there were small amounts of voids, unreacted MgB4 particles and MgO impurity existed in the superconducting layers, and the transport layer J c of the wire with the MgB4 precursor reached 3.0 × 104 A cm-2 at 4.2 K and 10 T, which was comparable to that of IMD-processed wires fabricated using boron precursors. Both the non-barrier J c and engineering J c of MgB2 wire made using a MgB4 precursor were enhanced due to the improved grain connectivity and the enlarged fill factor.

  2. Determination of the 36Mg(n ,γ )37Mg reaction rate from Coulomb dissociation of 37Mg

    Shubhchintak; Chatterjee, R.; Shyam, R.


    We use the Coulomb dissociation (CD) method to calculate the rate of the 36Mg(n ,γ )37Mg radiative capture reaction. The CD cross sections of the 37Mg nucleus on a 208Pb target at the beam energy of 244 MeV/nucleon, for which new experimental data have recently become available, were calculated within the framework of a finite-range distorted-wave Born approximation theory that is extended to include the projectile deformation effects. Invoking the principle of detailed balance, these cross sections are used to determine the excitation function and subsequently the rate of the 36Mg(n ,γ )37Mg reaction. We compare these rates to those of the 36Mg(α ,n )39Si reaction calculated within a Hauser-Feshbach model. We find that for T9 as large as up to 1.0 (in units of 109 K) the 36Mg(n ,γ )37Mg reaction is much faster than the 36Mg(α ,n )39Si one. The inclusion of the effects of 37Mg projectile deformation in the breakup calculations enhances the (n ,γ ) reaction rate even further. Therefore, it is highly unlikely that the (n ,γ )β -decay r -process flow will be broken at the 36Mg isotope by the α process.

  3. The coordination of Mg in foraminiferal calcite

    Branson, Oscar; Redfern, Simon A. T.; Tyliszczak, Tolek; Sadekov, Aleksey; Langer, Gerald; Kimoto, Katsunori; Elderfield, Henry


    The Mg/Ca ratio of foraminiferal calcite is a widely accepted and applied empirical proxy for ocean temperature. The analysis of foraminifera preserved in ocean sediments has been instrumental in developing our understanding of global climate, but the mechanisms behind the proxy are largely unknown. Analogies have been drawn to the inorganic precipitation of calcite, where the endothermic substitution of Mg for Ca is favoured at higher temperatures. However, evidence suggests that foraminiferal Mg incorporation may be more complex: foraminiferal magnesium is highly heterogeneous at the sub-micron scale, and high Mg areas coincide with elevated concentrations of organic molecules, Na, S and other trace elements. Fundamentally, the incorporation mode of Mg in foraminifera is unknown. Here we show that Mg is uniformly substituted for Ca within the calcite mineral lattice. The consistency of Mg-specific X-ray spectra gathered from nano-scale regions across the shell (‘test’) reveals that the coordination of Mg is uniform. The similarity of these spectra to that produced by dolomite shows that Mg is present in an octahedral coordination, ideally substituted for Ca in a calcite crystal structure. This demonstrates that Mg is heterogeneous in concentration, but not in structure. The degree of this uniformity implies the action of a continuous Mg incorporation mechanism, and therefore calcification mechanism, across these compositional bands in foraminifera. This constitutes a fundamental step towards a mechanistic understanding of foraminiferal calcification processes and the incorporation of calcite-bound palaeoenvironment proxies, such as Mg.

  4. Enhanced critical current density of in situ processed MgB{sub 2} bulk superconductors with MgB{sub 4} additions

    Kim, S. H.; Jun, B. H.; Lee, Y. J.; Kim, C. J. [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Kang, W. N. [Sungkyunkwan University, Suwon (Korea, Republic of)


    The effects of MgB{sub 4} addition on the superconducting properties and the microstructure of in situ processed MgB{sub 2} bulk superconductors were studied. MgB{sub 4} powder of 1-20 wt.% was mixed with (Mg + 2B) powder and then pressed into pellets. The pellets of (Mg + 2B + xMgB{sub 4}) were heat-treated at 650 ℃ for 1 h in flowing argon. The powder X-ray diffraction (XRD) analysis for the heat-treated samples showed that the major formed phase in all samples was MgB{sub 2} and the minor phases were MgB{sub 4} and MgO. The full width at half maximum (FWHM) values showed that the grain size of MgB{sub 2} decreased as the amount of MgB{sub 4} addition increased. MgB{sub 4} particles included in a MgB{sub 2} matrix is considered to suppress the grain growth of MgB{sub 2}. The onset temperatures (T{sub c},onset) of MgB{sub 2} with MgB{sub 4} addition (0-10 wt.%) was between 37-38 K. The 20 wt.% MgB{sub 4} addition slightly reduced the T{sub c},onset of MgB{sub 2} to 36.5 K. This result indicates that MgB{sub 4} addition did not influence the superconducting transition temperature (T{sub c}) of MgB{sub 2} significantly. On the other hand, the small additions of 1-5 wt.% MgB{sub 4} increased the critical current density (J{sub c}) of MgB{sub 2}. The Jc enhancement by MgB{sub 4} addition is attributed not only to the grain size refinement but also to the possible flux pinning of MgB{sub 4} particles dispersed in a MgB{sub 2} matrix.

  5. High-precision Mg isotopic systematics of bulk chondrites

    Schiller, Martin; Handler, Monica R.; Baker, Joel A.


    Variations of the mass-independent abundance of 26Mg ( δ26Mg*) and stable Mg ( δ25Mg) isotope composition of chondrites are important because they constrain the homogeneity of 26Al and Mg isotopes in the proto-planetary disc and the validity of the short-lived 26Al-to- 26Mg chronometer applied to meteorites. We present high-precision Mg isotope data and Al/Mg ratios of chondrites representing nearly all major chondrite classes, including a step-leaching experiment on the CM2 chondrite Murchison. δ26Mg* variations in leachates of Murchison representing acid soluble material are ≤ 30 times smaller than reported for neutron-rich isotopes of Ti and Cr and do not reveal resolvable deficits in δ26Mg* (-0.002 to + 0.118‰). Very small variations in δ26Mg* anomalies in bulk chondrites (-0.006 to + 0.019‰) correlate with increasing 27Al/ 24Mg ratios and δ50Ti, reflecting the variable presence of calcium-aluminium-rich inclusions (CAIs) in some types of carbonaceous chondrites. Similarly, release of radiogenic 26Mg produced by 26Al decay from CAI material in the step-leaching of Murchison best explains the high δ26Mg* observed in the last, aggressive, leaching steps of this experiment. Overall, the observed variations in δ26Mg* are small and potential differences beyond that which result from the presence of CAI-like material cannot be detected within the analytical uncertainties of this study (± 0.004‰). The results do not allow radical heterogeneity of 26Al (≥±30%) or measurable Mg nucleosynthetic heterogeneity (≥±0.005‰) to have existed on a planetesimal scale in the proto-planetary disc. Combined with published δ26Mg* data for CAIs, the bulk chondrite data yield a precise initial ( 26Al/ 27Al) 0 = (5.21 ± 0.06) × 10 -5 and δ26Mg* = -0.0340 ± 0.0016‰ for the Solar System. However, it is not possible with the currently available data to determine with certainty whether CAIs and the material from which planetesimals accreted including

  6. Modeling and stabilities of Mg/MgH2 interfaces: A first-principles investigation

    Tang, Jia-Jun; Yang, Xiao-Bao; Chen, Li-Juan; Zhao, Yu-Jun


    We have theoretically investigated the modeling and the structural stabilities of various Mg/MgH2 interfaces, i.e. Mg(10bar 10)/MgH2(210), Mg(0001)/MgH2(101) and Mg(10bar 10)/MgH2(101), and provided illuminating insights into Mg/MgH2 interface. Specifically, the main factors, which impact the interfacial energies, are fully considered, including surface energies of two phases, mutual lattice constants of interface model, and relative position of two phases. The surface energies of Mg and MgH2, on the one hand, are found to be greatly impacting the interfacial energies, reflected by the lowest interfacial energy of Mg(0001)/MgH2(101) which is comprised of two lowest energy surfaces. On the other hand, it is demonstrated that the mutual lattice constants and the relative position of two phases lead to variations of interfacial energies, thus influencing the interface stabilities dramatically. Moreover, the Mg-H bonding at interface is found to be the determinant of Mg/MgH2 interface stability. Lastly, interfacial and strain effects on defect formations are also studied, both of which are highly facilitating the defect formations. Our results provide a detailed insight into Mg/MgH2 interface structures and the corresponding stabilities.

  7. Modeling and stabilities of Mg/MgH2 interfaces: A first-principles investigation

    Jia-Jun Tang


    Full Text Available We have theoretically investigated the modeling and the structural stabilities of various Mg/MgH2 interfaces, i.e. Mg(101¯0/MgH2(210, Mg(0001/MgH2(101 and Mg(101¯0/MgH2(101, and provided illuminating insights into Mg/MgH2 interface. Specifically, the main factors, which impact the interfacial energies, are fully considered, including surface energies of two phases, mutual lattice constants of interface model, and relative position of two phases. The surface energies of Mg and MgH2, on the one hand, are found to be greatly impacting the interfacial energies, reflected by the lowest interfacial energy of Mg(0001/MgH2(101 which is comprised of two lowest energy surfaces. On the other hand, it is demonstrated that the mutual lattice constants and the relative position of two phases lead to variations of interfacial energies, thus influencing the interface stabilities dramatically. Moreover, the Mg-H bonding at interface is found to be the determinant of Mg/MgH2 interface stability. Lastly, interfacial and strain effects on defect formations are also studied, both of which are highly facilitating the defect formations. Our results provide a detailed insight into Mg/MgH2 interface structures and the corresponding stabilities.

  8. Colloidal processing of alumina with MgO additions

    Lyckfeldt, O. [Swedish Ceramic Inst., Goeteborg (Sweden); Ferreira, J.M.F. [Dept. of Ceramics and Glass Engineering, Univ. of Aveiro (Portugal)


    Both rheological studies and casting studies were made to evaluate the effects of adding MgO (0.10 wt%) to alumina slips with a solids loading of 45 vol%, stabilised either with a polyacrylic acid (Dispex A40, Allied Colloids Ltd, UK) or with a low M{sub w} sulphonic acid (Tiron, Aldrich Chemie, Germany). Tiron and Dispex are expected to give electrostatic and electrosteric stabilisation, respectively. The addition of MgO gave significant effects displayed by increased viscosity and elasticity of the slips and a considerable decrease in density of slip-cast and filter-pressed bodies. When the casting pressure increased, there was also a general tendency that the density of filter-pressed bodies decreased with well-stabilised slips (without MgO), but increased when the slip was weakly flocculated (with MgO). This was explained by the casting rate dependency under stabilised slip conditions, and the compressibility of the filter-pressed cakes formed using flocculated slips. Furthermore, it was shown that Tiron gave a higher degree of deflocculation both with addition of MgO and without MgO, indicating that the electrostatic stabilising mechanism dominates the particle interactions whereas steric effects are less important at the solids loading used. (orig.) 5 refs.

  9. Ipilimumab 10 mg/kg versus ipilimumab 3 mg/kg in patients with unresectable or metastatic melanoma

    Ascierto, Paolo A; Del Vecchio, Michele; Robert, Caroline


    BACKGROUND: A phase 2 trial suggested increased overall survival and increased incidence of treatment-related grade 3-4 adverse events with ipilimumab 10 mg/kg compared with ipilimumab 3 mg/kg in patients with advanced melanoma. We report a phase 3 trial comparing the benefit-risk profile...... of ipilimumab 10 mg/kg versus 3 mg/kg. METHODS: This randomised, double-blind, multicentre, phase 3 trial was done in 87 centres in 21 countries worldwide. Patients with untreated or previously treated unresectable stage III or IV melanoma, without previous treatment with BRAF inhibitors or immune checkpoint...... for metastatic melanoma, and Eastern Cooperative Oncology Group performance status. The patients, investigators, and site staff were masked to treatment assignment. The primary endpoint was overall survival in the intention-to-treat population and safety was assessed in all patients who received at least one...

  10. First-principle Calculations of Mechanical Properties of Al2Cu, Al2CuMg and MgZn2 Intermetallics in High Strength Aluminum Alloys

    LIAO Fei


    Full Text Available Structural stabilities, mechanical properties and electronic structures of Al2Cu, Al2CuMg and MgZn2 intermetallics in Al-Zn-Mg-Cu aluminum alloys were determined from the first-principle calculations by VASP based on the density functional theory. The results show that the cohesive energy (Ecoh decreases in the order MgZn2 > Al2CuMg > Al2Cu, whereas the formation enthalpy (ΔH decreases in the order MgZn2 > Al2Cu > Al2CuMg. Al2Cu can act as a strengthening phase for its ductile and high Young's modulus. The Al2CuMg phase exhibits elastic anisotropy and may act as a crack initiation point. MgZn2 has good plasticity and low melting point, which is the main strengthening phase in the Al-Zn-Mg-Cu aluminum alloys. Metallic bonding mode coexists with a fractional ionic interaction in Al2Cu, Al2CuMg and MgZn2, and that improves the structural stability. In order to improve the alloys' performance further, the generation of MgZn2 phase should be promoted by increasing Zn content while Mg and Cu contents are decreased properly.

  11. Chronic glucose infusion causes sustained increases in tubular sodium reabsorption and renal blood flow in dogs.

    Brands, Michael W; Bell, Tracy D; Rodriquez, Nancy A; Polavarapu, Praveen; Panteleyev, Dmitriy


    This study tested the hypothesis that inducing hyperinsulinemia and hyperglycemia in dogs, by infusing glucose chronically intravenously, would increase tubular sodium reabsorption and cause hypertension. Glucose was infused for 6 days (14 iv) in five uninephrectomized (UNX) dogs. Mean arterial pressure (MAP) and renal blood flow (RBF) were measured 18 h/day using DSI pressure units and Transonic flow probes, respectively. Urinary sodium excretion (UNaV) decreased significantly on day 1 and remained decreased over the 6 days, coupled with a significant, sustained increase in RBF, averaging approximately 20% above control on day 6. Glomerular filtration rate and plasma renin activity (PRA) also increased. However, although MAP tended to increase, this was not statistically significant. Therefore, the glucose infusion was repeated in six dogs with 70% surgical reduction in kidney mass (RKM) and high salt intake. Blood glucose and plasma insulin increased similar to the UNX dogs, and there was significant sodium retention, but MAP still did not increase. Interestingly, the increases in PRA and RBF were prevented in the RKM dogs. The decrease in UNaV, increased RBF, and slightly elevated MAP show that glucose infusion in dogs caused a sustained increase in tubular sodium reabsorption by a mechanism independent of pressure natriuresis. The accompanying increase in PRA, together with the failure of either RBF or PRA to increase in the RKM dogs, suggests the site of tubular reabsorption was before the macula densa. However, the volume retention and peripheral edema suggest that systemic vasodilation offsets any potential renal actions to increase MAP in this experimental model in dogs.

  12. Corrosion behavior of Mg and Mg-Zn alloys in simulated body fluid

    GAO Jia-cheng; WU Sha; QIAO Li-ying; WANG Yong


    The corrosion behavior of Mg and Mg-Zn in simulated body fluid was studied.The mass loss of pure Mg,Mg-Zn-Zr and Mg-Zn-Zr-Y in simulated body fluid was measured using photovoltaic scale meter.Corrosion rate was determined through electrochemical tests.Finally,the corrosion mechanism was tbermodynamically studied.The results show that the corrosion rate decreases with the lapse of time for both pure Mg and Mg alloys.The purer the alloy,the borer the corrosion resistance exhibits.The corrosion behavior of Mg alloy is improved by the addition of trace Y.

  13. XPS analyses of Ta/MgO{sub x}/Ni{sub 81}Fe{sub 19}/MgO{sub x}/Ta films

    Li Minghua, E-mail: [Department of Material Physics and Chemistry, University of Science and Technology Beijing, Beijing 100083 (China); Han Gang; Liu Yang; Feng Chun; Wang Haicheng; Teng Jiao; Yu Guanghua [Department of Material Physics and Chemistry, University of Science and Technology Beijing, Beijing 100083 (China)


    Highlights: Black-Right-Pointing-Pointer Ta/MgO{sub x}/Ni{sub 81}Fe{sub 19}/MgO{sub x}/Ta films were prepared by magnetron sputtering. The anisotropic magnetoresistance (AMR) increases dramatically after annealing. Black-Right-Pointing-Pointer The chemical states of Ta and MgO{sub x} at the interface of the NiFe/MgO{sub x}/Ta films, which were prepared at the different technological conditions, were analyzed by X-ray photoelectron spectroscopy (XPS). Black-Right-Pointing-Pointer The AMR of Ta/MgO{sub x}/Ni{sub 81}Fe{sub 19}/MgO{sub x}/Ta films is related to the chemical states of MgO{sub x}. These states were produced under different technical conditions and influence the film properties. - Abstract: Ta/MgO{sub x}/Ni{sub 81}Fe{sub 19}/MgO{sub x}/Ta films were prepared by magnetron sputtering. The anisotropic magnetoresistance (AMR) increases dramatically after annealing. The chemical states of Ta and MgO{sub x} at the interface of the NiFe/MgO{sub x}/Ta films, which were prepared at the different technological conditions, were analyzed by X-ray photoelectron spectroscopy (XPS). The results show that the AMR of the films is related to the chemical states of MgO{sub x}. The chemical states of Mg are different when MgO{sub x} is prepared at different technological conditions. Therefore, increasing the AMR is beneficial when more Mg{sup 2+} ions are present in the MgO{sub x} films.

  14. Facile fabrication of hydrophobic surfaces on mechanically alloyed-Mg/HA/TiO{sub 2}/MgO bionanocomposites

    Khalajabadi, Shahrouz Zamani [Medical Devices and Technology Group (MEDITEG), Faculty of Biosciences and Medical Engineering, Universiti Teknologi Malaysia, 81310 Johor Bahru, Johor (Malaysia); Abdul Kadir, Mohammed Rafiq, E-mail: [Medical Devices and Technology Group (MEDITEG), Faculty of Biosciences and Medical Engineering, Universiti Teknologi Malaysia, 81310 Johor Bahru, Johor (Malaysia); Izman, Sudin; Mohd Yusop, Mohd Zamri [Department of Materials, Manufacturing and Industrial Engineering, Faculty of Mechanical Engineering, Universiti Teknologi Malaysia, 81310 Johor Bahru, Johor (Malaysia)


    Highlights: • Mg/HA/TiO{sub 2}-based nanocomposite was produced using mechanical alloying. • The hydrophobic surface coverage was fabricated on the mechanical alloyed samples by annealing. • The morphological characteristics, phase evolution and wettability of nanocomposites and the hydrophobic surface coverage were investigated. • The activation energies and reaction kinetic of the powder mixture of nanocomposites were calculated. - Abstract: The effect of mechanical alloying and post-annealing on the phase evolution, microstructure, wettability and thermal stability of Mg–HA–TiO{sub 2}–MgO composites was investigated in this study. Phase evolution and microstructure analysis were performed using X-ray diffraction, field-emission scanning electron microscopy, transmission electron microscopy and atomic force microscopy, as well as the wettability determined by contact angle measurements with SBF. The 16-h mechanical alloying resulted in the formation of MgTiO{sub 3}, CaTiO{sub 3}, Mg{sub 3}(PO{sub 4}){sub 2} and Mg(OH){sub 2} phases and a decrease in wettability of the nanocomposites. A hydrophobic film with hierarchical structures comprising nanoflakes of MgTiO{sub 3}, nano-cuboids of CaTiO{sub 3}, microspheres of Mg{sub 3}(PO{sub 4}){sub 2} and Mg(OH){sub 2} was successfully constructed on the surface of the Mg-based nanocomposites substrates as a result of the post-annealing process. After 1-h annealing at 630 °C, the synthesized hydrophobic surface on the nanocomposite substrates decreased the wettability, as the 8-h-mechanically alloyed samples exhibited a contact angle close to 93°. The formation activation energies and reaction kinetics of the powder mixture were investigated using differential thermal analysis and thermal gravimetric analysis. The released heat, weight loss percentage and reaction kinetics increased, while the formation activation energies of the exothermic reactions decreased following an increase in the milling time.

  15. Green tea extract increases cyclophosphamide-induced teratogenesis by modulating the expression of cytochrome P-450 mRNA.

    Park, Dongsun; Jeon, Jeong Hee; Shin, Sunhee; Joo, Seong Soo; Kang, Dae-Hyuck; Moon, Seol-Hee; Jang, Min-Jung; Cho, Yeoung Mi; Kim, Jae Wook; Ji, Hyeong-Jin; Ahn, Byeongwoo; Oh, Ki-Wan; Kim, Yun-Bae


    The effects of green tea extract (GTE) on the fetal development and external, visceral and skeletal abnormalities induced by cyclophosphamide were investigated in rats. Pregnant rats were daily administered GTE (100mg/kg) by gavage for 7 d, from the 6th to 12th day of gestation, and intraperitoneally administered with cyclophosphamide (11mg/kg) 1h after the final treatment. On the 20th day of gestation, maternal and fetal abnormalities were determined by Cesarian section. Cyclophosphamide was found to reduce fetal and placental weights without increasing resorption or death. In addition, it induced malformations in live fetuses; 94.6%, 41.5% and 100% of the external (skull and limb defects), visceral (cleft palate and ureteric dilatation) and skeletal (acrania, vertebral/costal malformations and delayed ossification) abnormalities. When pre-treated with GTE, cyclophosphamide-induced body weight loss and abnormalities of fetuses were remarkably aggravated. Moreover, repeated treatment with GTE greatly increased mRNA expression and activity of hepatic cytochrome P-450 (CYP) 2B, which metabolizes cyclophosphamide into teratogenic acrolein and cytotoxic phosphoramide mustard, while reducing CYP3A expression (a detoxifying enzyme). The results suggest that repeated intake of GTE may aggravate cyclophosphamide-induced body weight loss and malformations of fetuses by modulating CYP2B and CYP3A.

  16. Magnetite recovery from copper tailings increases arsenic distribution in solution phase and uptake in native grass.

    Liu, Yunjia; Huang, Longbin


    Reprocessing magnetite-rich copper (Cu) tailings prompted a concern about arsenic (As) risks in seepage water and revegetated plants at Ernest Henry Cu Mine (EHM) in North Queensland, Australia, due to the closely coupled relationship between iron (Fe) minerals and As mobility. The magnetite removal alone significantly decreased the content of crystalline Fe minerals and the maximum arsenate (As(V)) sorption capacity of the resultant tailings. A glasshouse experiment with native grass Red Flinders (Iseilema Vaginiflorum) was conducted with the reprocessed (low magnetite (LM)) and original (high magnetite (HM)) tailings, which were amended with 5% sugarcane residue (SR) as a basal treatment in combination with 0, 1 and 5% pine-biochar (BC). The organic matter treatments and plant growth stimulated the formation of secondary Fe minerals. The amount of extractable amorphous Fe in the amended and revegetated HM tailings was significantly higher than those in the LM. Arsenic forms in the specifically sorbed and the sorbed by amorphous Fe oxides were significantly increased by the SR amendment in the LM tailings, but which were decreased in the HM, compared to the unamended tailings. Soluble As levels in the porewater of the LM under revegetation were significantly higher (300-1150 μg As L(-1)) than those (up to 45-90 μg As L(-1)) in HM tailings in the same treatment, which led to the higher As concentrations in the plants grown in the LM tailings. In particular, root As concentration (62-146 mg kg(-1)) in the LM tailings was almost a magnitude higher than those (8-17 mg kg(-1)) in the HM. The present results confirmed the initial expectation that the recovery of magnetite from the Cu tailings significantly elevated the risk of As solubility in the tailings by decreasing As sorption capacity and increasing soluble As levels. Thus, it would be beneficial to retain high contents of magnetite in the top layer (e.g., root zone) of the Cu tailings for managing As

  17. Effect of Mg on microstructures and properties of Al-Mg-Si-Cu aluminium alloys for automotive body sheets

    LIU Hong; SONG Wen-ju; ZHAO Gang; LIU Chun-ming; ZUO Liang


    The effects of variation of Mg content on microstructures,the tensile properties and the formability of Al-Mg-Si-Cu alloys for automotive body sheets were investigated by means of scan electron microscopy,optical metallographic analysis,tensile and Ericsson tests.The results show that for Al-Mg-Si-Cu aluminium alloys with excessive Si,with an increment of Mg content,the strength enhances,the specific elongation and Erisson values of alloys decrease,and the number of Mg2 Si constituent increases and that of Al(MnFe)Si type constituents reduces.Al-MgSi-Cu aluminium alloys with excessive Si for automotive body sheets can present obviously the paint bake hardenability during the paint bake cycle (I.e.artificial aging at 170 ℃ for 30 min immediately after the solution treatment and quenching).Suitable Mg content should be controlled in the range of 0.8% and 1.2 % (mass fraction).

  18. Effects of magnesium contents in ZnMgO ternary alloys grown by molecular beam epitaxy

    Hu, Sheng-Yao, E-mail: [Department of Digital Technology Design, Tungfang Design Institute, Hunei, Kaohsiung 82941, Taiwan (China); Chou, Wu-Ching [Department of Electrophysics, National Chiao Tung University, Hsinchu 30010, Taiwan (China); Weng, Yu-Hsiang [Department of Electrical Engineering, National Taiwan Ocean University, Keelung 20224, Taiwan (China)


    Highlights: • ZnMgO alloys with different Mg contents have been produced by MBE. • Optical and structural properties have been measured and investigated. • Stress is tensile and is increased as the increasing of Mg contents. • The asymmetric behavior of the Raman mode was influenced due to the Mg contents. - Abstract: Ternary alloys of ZnMgO samples with different magnesium contents have been grown by molecular beam epitaxy on the sapphire substrates. Room temperature photoluminescence energy of ZnMgO shifted as high as 3.677 eV by increasing Mg contents corresponding to the higher Urbach average localization energy which indicates more randomness in the alloys with higher Mg contents. XRD results are also verified that the c-axis length decreases as the increasing Mg contents linking to the increased tensile stress produced by the Mg atoms. Raman spectra analyzed by the spatial correlation model to describe that the linewidth Γ is decreased but the correlation length L is increased as the increasing of Mg contents.

  19. Influence of Alloying Treatment and Rapid Solidification on the Degradation Behavior and Mechanical Properties of Mg

    Jian Chen


    Full Text Available Magnesium (Mg has drawn increasing attention as a tissue engineering material. However, there have been very few studies of laser-melted Mg-Zn alloys. In this study, four binary Mg-xZn (x = 2, 4, 6 and 8 wt. % alloys were fabricated by laser melting. The influence of zinc (Zn content and technique on the degradation behavior and mechanical properties of Mg were discussed. Results revealed that Mg-xZn alloys consisted of an α-Mg matrix and MgZn phases, which dispersed at the grain boundaries. In addition, the MgZn phase increased with the increase in Zn content. The laser-melted alloy had fine homogenous grains, with an average grain size of approximately 15 μm. Grain growth was effectively inhibited due to the precipitation of the MgZn phase and rapid solidification. Grain refinement consequently slowed down the degradation rate, with Zn content increasing to 6 wt. %. However, a further increase of Zn content accelerated the degradation rate due to the galvanic couple effect between α-Mg and MgZn. Moreover, the mechanical properties were improved due to the grain refinement and reinforcement of the MgZn phase.

  20. The conduction bands of MgO, MgS and HfO2

    Boer, P.K. de; Groot, R.A. de


    Electronic structure calculations for MgO, MgS and HfO2 are reported. It is shown that the conduction bands of MgO and MgS have predominantly anion character, contrary to the common picture of the conduction band being derived from cation states. In transition metal oxides, unoccupied anion states a

  1. TRPM6 forms the Mg2+ influx channel involved in intestinal and renal Mg2+ absorption.

    Voets, T.; Nilius, B.; Hoefs, S.J.G.; Kemp, J.W.C.M. van der; Droogmans, G.; Bindels, R.J.M.; Hoenderop, J.G.J.


    Mg2+ is an essential ion involved in a multitude of physiological and biochemical processes and a major constituent of bone tissue. Mg2+ homeostasis in mammals depends on the equilibrium between intestinal Mg2+ absorption and renal Mg2+ excretion, but little is known about the molecular nature of

  2. The Dissolution Kinetics of MgO into CaO-MgO-Fe2O3 Slag

    Wei, Ruirui; Lv, Xuewei; Yue, Zhiwen; Xiang, Shenglin


    Calcium ferrite is the main binding phase for high-basicity sinter. The production and structure of calcium ferrite greatly influence the quality of the sinter. With the change in gangue composition, MgO becomes an important factor in the generation of calcium ferrite. In this study, the rotating cylinder method was used to study the dissolution kinetics of MgO into CaO-MgO-Fe2O3 melt. The experimental variables included the temperature, the initial composition of the melt, the Fe2O3/CaO mass ratio, the rotation time, and the rotation speed. The results indicate that the dissolution rate increases with increasing dissolution time, temperature, and rotation speed but decreases with increasing MgO content and Fe2O3/CaO mass ratio in the initial slag. The dissolution rate was observed to increase and then decrease with the addition of SiO2 in the initial slag. The activation energy and diffusion coefficient for MgO dissolution were found to range from 117.31 to 234.24 kJ mol-1 and from 1.03 × 10-6 to 1.18 × 10-5 cm2 s-1, respectively. The concentration difference between the solid and liquid phases is the main driving force for dissolution, but the viscosity and magnesium ion diffusivity of the melt also affect the process.

  3. Selection of dopants to enhance hydrogen diffusion rates in MgH2 and NaMgH3

    Hao, Shiqiang; Sholl, David S.


    The transport properties of hydrogen in metal hydrides are crucial to the kinetics of H2 storage in these materials. Previous first-principles calculations and experiments have shown that H transport in MgH2 and NaMgH3 is dominated by charged defects. This creates the possibility of enhancing hydrogen diffusion in these materials by adding dopants that alter the population of the relevant charged defects. We describe a comprehensive set of first-principles calculations examining dopants in MgH2 and NaMgH3 for this purpose. Only a small number of elemental dopants are found to have favorable properties, but these dopants could increase the diffusivity of H by two to three orders of magnitude relative to the undoped materials.

  4. Mechanical Spectroscopy of MgB2 Containing Sic / Spektroskopia Mechaniczna MgB2 Zawierającego Sic

    Silva M.R.


    Full Text Available The compound magnesium diboride (MgB2 has been well-known since the 1950s; however, its superconducting properties were unknown. Intrinsic characteristics of MgB2 make this material a promising candidate for technological applications, although the low value of the irreversibility field and the decrease in critical current density with the increase in the magnetic field considerably reduce its utility. The present work aimed to study the effect of carbon-based doping on anelastic properties of MgB2 as measured by mechanical spectroscopy. The samples were prepared by using the powder-intube method. The samples were made with 5, 7.5, and 10 wt.% of silicon carbide (SiC. The results reveal complex mechanical loss spectra caused by the interaction between point defects and surface defects in the crystalline lattice of MgB2.

  5. Hydrogen storage systems from waste Mg alloys

    Pistidda, C.; Bergemann, N.; Wurr, J.; Rzeszutek, A.; Møller, K. T.; Hansen, B. R. S.; Garroni, S.; Horstmann, C.; Milanese, C.; Girella, A.; Metz, O.; Taube, K.; Jensen, T. R.; Thomas, D.; Liermann, H. P.; Klassen, T.; Dornheim, M.


    The production cost of materials for hydrogen storage is one of the major issues to be addressed in order to consider them suitable for large scale applications. In the last decades several authors reported on the hydrogen sorption properties of Mg and Mg-based systems. In this work magnesium industrial wastes of AZ91 alloy and Mg-10 wt.% Gd alloy are used for the production of hydrogen storage materials. The hydrogen sorption properties of the alloys were investigated by means of volumetric technique, in situ synchrotron radiation powder X-ray diffraction (SR-PXD) and calorimetric methods. The measured reversible hydrogen storage capacity for the alloys AZ91 and Mg-10 wt.% Gd are 4.2 and 5.8 wt.%, respectively. For the Mg-10 wt.% Gd alloy, the hydrogenated product was also successfully used as starting reactant for the synthesis of Mg(NH2)2 and as MgH2 substitute in the Reactive Hydride Composite (RHC) 2LiBH4 + MgH2. The results of this work demonstrate the concrete possibility to use Mg alloy wastes for hydrogen storage purposes.

  6. Coherent interface structures and intergrain Josephson coupling in dense MgO/Mg2Si/MgB2 nanocomposites

    Ueno, Katsuya; Nagashima, Yukihito; Seto, Yusuke; Matsumoto, Megumi; Sakurai, Takahiro; Ohta, Hitoshi; Takahashi, Kazuyuki; Uchino, Takashi


    Many efforts are under way to control the structure of heterointerfaces in nanostructured composite materials for designing functionality and engineering application. However, the fabrication of high-quality heterointerfaces is challenging because the crystal/crystal interface is usually the most defective part of the nanocomposite materials. In this work, we show that fully dense insulator (MgO)/semiconductor(Mg2Si)/superconductor(MgB2) nanocomposites with atomically smooth and continuous interfaces, including epitaxial-like MgO/Mg2Si interfaces, are obtained by solid phase reaction between metallic magnesium and a borosilicate glass. The resulting nanocomposites exhibit a semiconductor-superconducting transition at 36 K owing to the MgB2 nanograins surrounded by the MgO/Mg2Si matrix. This transition is followed by the intergrain phase-lock transition at ˜24 K due to the construction of Josephson-coupled network, eventually leading to a near-zero resistance state at 17 K. The method not only provides a simple process to fabricate dense nanocomposites with high-quality interfaces, but also enables to investigate the electric and magnetic properties of embedded superconducting nanograins with good intergrain coupling.

  7. Impact of amorphous precursor phases on magnesium isotope signatures of Mg-calcite

    Mavromatis, Vasileios; Purgstaller, Bettina; Dietzel, Martin; Buhl, Dieter; Immenhauser, Adrian; Schott, Jacques


    Various marine calcifiers form exoskeletons via an amorphous calcium carbonate (ACC) precursor phase and magnesium plays an important role in the temporary stabilization of this metastable phase. Thus, the use of Mg isotope ratios of marine biogenic carbonates as a proxy to reconstruct past seawater chemistry calls for a detailed understanding of the mechanisms controlling Mg isotope signatures during the formation and transformation of ACC to the final crystalline carbonate mineral. For this purpose we have investigated the Mg isotope fractionation between (Ca,Mg)CO3 solids and aqueous fluids at 25 °C and pH = 8.3 during (i) the direct precipitation of crystalline Mg-calcite and (ii) the formation of Mg-rich ACC (Mg-ACC) and its transformation to Mg-calcite. The outcome documents that the small Mg isotope fractionation between Mg-ACC and reactive fluid (ΔMg26ACC-fluid = - 1.0 ± 0.1 ‰) is not preserved during the transformation of the ACCs into Mg-calcite. Following a pronounced isotopic shift accompanying the transformation of Mg-ACC into Mg-calcite, Δ26Mgcalcite-fluid progressively decreases with reaction progress from ∼ - 3.0 ‰ to - 3.6 ‰, reflecting both the approach of isotopic equilibrium and the increase of calcite Mg content (to near 20 mol % Mg). In contrast the crystalline Mg-calcite precipitated directly from the reacting fluid, i.e. lacking a discernable formation of an amorphous precursor, exhibits only small temporal variations in Δ26Mgcalcite-fluid which overall is affected by the precipitation kinetics. The values found in this study at the onset of Mg-ACC precipitation for Mg isotope fractionation between Mg-ACC and the fluid (ΔMg26ACC-fluid = - 1.0 ‰) and between Mg-ACC and Mg2+(aq) (Δ(aq) 26 Mg ACC-Mg2+ = + 2.0 ‰) are consistent with the formation of a hydrated Ca nanoporous solid accommodating Mg bicarbonate/carbonate species in combination with hydrated magnesium. This material crossed by percolating channels filled with the

  8. The Coordination of Mg in Foraminiferal Calcite

    Branson, O.; Redfern, S. A.; Tyliszczak, T.; Sadekov, A.; Langer, G.; Elderfield, H.


    The Mg/Ca ratio in calcite shells ('tests') of foraminifera is an empirical ocean temperature proxy widely used to interpret palaeoclimates. We explore the distribution and local environment of Mg in foram tests using STXM and NEXAFS spectroscopy to test the fundamental assumptions behind the proxy, and shed light on the mechanisms underpinning this vital oceanographic tool. Throughout the development of the Mg/Ca proxy, it has been assumed that Mg in foraminifera tests substitutes directly into the calcite lattice (1). This assumption is based on XRD analyses of various high-Mg biogenic carbonates, where Mg concentrations are manifest in the shifted position of diffraction peaks (2, 3). The extrapolation of this trend to foraminiferal calcite links the proxy to inorganic precipitation experiments, and provides a theoretical mechanistic framework to understand the link between Mg/Ca and temperature: the substitution of Mg is endothermic, and favoured at higher temperatures. However, the concentration of Mg in most foraminifera (0-10 mmol/mol Mg/Ca) is below the detection limit of XRD methods, and the analogy to inorganic systems has not been explicitly tested. Electron microprobe (4-6), LA-ICP-MS (7) and high-resolution nanoSIMS mapping (Sadekov, unpub.) of foraminifera tests have revealed the presence of high 'trace element' bands running in plane with the test surface, enriched in Mg, Sr, S, organic molecules and other trace elements. This emphasises a key question highlighted by Dodd (1) when the proxy was still in its infancy: how is Mg incorporated into mineral skeletons? By direct substitution into the calcite lattice, interstitially in a separate distinct mineral phase, or associated with organic compounds? We address this fundamental question using scanning transmission X-ray microscopy (STXM) and X-ray absorption spectroscopy at ALS beamline 11.0.2 to examine the distribution and local atomic environment of Mg in two contrasting species of foraminifera

  9. Existing form and effect of zirconium in pure Mg, Mg-Yb, and Mg-Zn-Yb alloys

    YU Wenbin; HE Hong; LI Chunmei; LI Qing; LIU Zhiyi; QIN Bing


    The existing form and grain refining effects of small zirconium addition in pure Mg, Mg-Yb and Mg-Zn binary alloys, and Mg-Zn-Yb ternary alloy (ZK60-Yb) were investigated. The results show that Zr element exists mainly in single and cluster particles of pure α-Zr or Zn-Zr compounds inside grains and at grain boundaries. Only the particles located in the interior of grains can act as the nucleus for α-Mg growth and effectively promote the formation of Fine equiaxed grains. The broken and dispersed Zr-rich particles produced during the hot extrusion process can form nebulous banded structure in which these free particles may act as obstacles to dislocation motion in wrought magnesium alloys.

  10. Investigation on the electrochemical behaviours of Mg2-xCrxNi negative electrode


    A series of Mg2-xCrxNi alloy powder has been produced by combination of solid-state diffusion with mechanicalgrinding (MG). X-ray diffraction patterns show that the alloy powders have an amorphous structure and great increase in thespecific surface. Electrochemical detection results indicate that the partial substitution of Mg by Cr in Mg2Ni alloy improvesthe cycle life of this alloy greatly, which gets up to 100 cycles at 200 mA/g mass discharge current, keeping its mass dis-charge capacity over 200 mA@h/g. In the meanwhile, partial replacement of Mg by Cr also increases the mass discharge ca-pacity compared with Mg2Ni alloy. With the increasing of mass discharge current and content of Cr in Mg2-xCrxNi, the cyclelife of the alloys are increased and the decay of mass discharge capacity slows down.

  11. Zinc, iron, manganese and copper uptake requirement in response to nitrogen supply and the increased grain yield of summer maize.

    Xue, Yanfang; Yue, Shanchao; Zhang, Wei; Liu, Dunyi; Cui, Zhenling; Chen, Xinping; Ye, Youliang; Zou, Chunqin


    The relationships between grain yields and whole-plant accumulation of micronutrients such as zinc (Zn), iron (Fe), manganese (Mn) and copper (Cu) in maize (Zea mays L.) were investigated by studying their reciprocal internal efficiencies (RIEs, g of micronutrient requirement in plant dry matter per Mg of grain). Field experiments were conducted from 2008 to 2011 in North China to evaluate RIEs and shoot micronutrient accumulation dynamics during different growth stages under different yield and nitrogen (N) levels. Fe, Mn and Cu RIEs (average 64.4, 18.1 and 5.3 g, respectively) were less affected by the yield and N levels. ZnRIE increased by 15% with an increased N supply but decreased from 36.3 to 18.0 g with increasing yield. The effect of cultivars on ZnRIE was similar to that of yield ranges. The substantial decrease in ZnRIE may be attributed to an increased Zn harvest index (from 41% to 60%) and decreased Zn concentrations in straw (a 56% decrease) and grain (decreased from 16.9 to 12.2 mg kg-1) rather than greater shoot Zn accumulation. Shoot Fe, Mn and Cu accumulation at maturity tended to increase but the proportions of pre-silking shoot Fe, Cu and Zn accumulation consistently decreased (from 95% to 59%, 90% to 71% and 91% to 66%, respectively). The decrease indicated the high reproductive-stage demands for Fe, Zn and Cu with the increasing yields. Optimized N supply achieved the highest yield and tended to increase grain concentrations of micronutrients compared to no or lower N supply. Excessive N supply did not result in any increases in yield or micronutrient nutrition for shoot or grain. These results indicate that optimized N management may be an economical method of improving micronutrient concentrations in maize grain with higher grain yield.

  12. Zinc, iron, manganese and copper uptake requirement in response to nitrogen supply and the increased grain yield of summer maize.

    Yanfang Xue

    Full Text Available The relationships between grain yields and whole-plant accumulation of micronutrients such as zinc (Zn, iron (Fe, manganese (Mn and copper (Cu in maize (Zea mays L. were investigated by studying their reciprocal internal efficiencies (RIEs, g of micronutrient requirement in plant dry matter per Mg of grain. Field experiments were conducted from 2008 to 2011 in North China to evaluate RIEs and shoot micronutrient accumulation dynamics during different growth stages under different yield and nitrogen (N levels. Fe, Mn and Cu RIEs (average 64.4, 18.1 and 5.3 g, respectively were less affected by the yield and N levels. ZnRIE increased by 15% with an increased N supply but decreased from 36.3 to 18.0 g with increasing yield. The effect of cultivars on ZnRIE was similar to that of yield ranges. The substantial decrease in ZnRIE may be attributed to an increased Zn harvest index (from 41% to 60% and decreased Zn concentrations in straw (a 56% decrease and grain (decreased from 16.9 to 12.2 mg kg-1 rather than greater shoot Zn accumulation. Shoot Fe, Mn and Cu accumulation at maturity tended to increase but the proportions of pre-silking shoot Fe, Cu and Zn accumulation consistently decreased (from 95% to 59%, 90% to 71% and 91% to 66%, respectively. The decrease indicated the high reproductive-stage demands for Fe, Zn and Cu with the increasing yields. Optimized N supply achieved the highest yield and tended to increase grain concentrations of micronutrients compared to no or lower N supply. Excessive N supply did not result in any increases in yield or micronutrient nutrition for shoot or grain. These results indicate that optimized N management may be an economical method of improving micronutrient concentrations in maize grain with higher grain yield.

  13. Mg-aminoclay as stabilizer for synthesizing highly stable and reactive nZVI for decontamination

    Hwang, Yuhoon; Lee, Young-Chul; Mines, Paul D.

    Despite the large surface area and superior reactivity of nZVI, its limited stability is a major obstacle for in situ subsurface remediation. In this study, Mg-aminoclay (MgAC) was applied for the first time as a stabilizer in nZVI synthesis. With increased doses of Mg-aminoclay, nZVI particle gr...

  14. Physiological characterization of grapevine rootstocks grown in soil with increasing zinc doses

    Jovani Zalamena


    Full Text Available ABSTRACTThis study aimed to evaluate the performance of grapevine rootstocks under increasing levels of Zn in the soil and to identify physiological variables that can be used as indicators of excess of Zn in the soil. The rootstocks SO4, Paulsen1103, IAC572, IAC313 and 420A were grown in pots containing soil, which received Zn doses of 0, 20, 40, 80 or 160 mg kg-1 of soil. Dry matter (DM, Zn content in shoots and roots, chlorophyll index, initial fluorescence (Fo, maximum fluorescence (Fm, maximum quantum yield of photosystem II (Fv/Fm, effective quantum yield of photosystem II (Y-II and non-photochemical quenching (NPQ were evaluated. The increase of Zn levels in the soil decreased DM in all rootstocks, and IAC572 was superior to the others. The variation in the indices of chlorophyll a and b had little expression in relation the soil Zn levels, but allowed identifying that the rootstocks Paulsen 1103, 420A and SO4 are sensitive to Zn toxicity and that IAC572 and IAC313 were not sensitive to the tested levels. Fluorescence analysis showed a negative effect of Zn contents on the variables Fo, Fm, Y-II and NPQ in all rootstocks, which proved to be good indicators of Zn phytotoxicity.

  15. A single dose of esmolol blunts the increase in bispectral index to tracheal intubation during sevoflurane but not desflurane anesthesia.

    Choi, Seung Ho; Kim, Chang Seok; Kim, Jong Hoon; Kim, Bum Su; Kim, Eun Mi; Min, Kyeong Tae


    Activation of the peripheral nerve system by endotracheal intubation is accompanied by an increase in bispectral index (BIS). Esmolol produces a dose-dependent attenuation of the adrenergic response to endotracheal intubation. Desflurane increases sympathetic nerve activity and plasma norepinephrine relative to sevoflurane. The authors hypothesized that esmolol might blunt the BIS response to endotracheal intubation more during sevoflurane anesthesia than desflurane anesthesia. In this double blind, randomized study, after the induction of anesthesia, patients were mask-ventilated with either sevoflurane or desflurane (end-tidal 1 minimum alveolar concentration) and received normal saline or esmolol (0.5 mg/kg) 1 minute before intubation (sevoflurane-control, sevoflurane-esmolol, desflurane-control, and desflurane-esmolol groups, n=20/group). BIS, mean arterial pressure, and heart rate were measured before the induction of anesthesia (awake), before esmolol injection (time point -1), immediately before intubation (time point 0), and every minute for 5 minutes after tracheal intubation (time point 1 to 5). Compared with preintubation, esmolol attenuated the increase in BIS at 1 minute after intubation during sevoflurane anesthesia (5.1% for esmolol and 31.7% for control) but not during desflurane anesthesia (28.6% for esmolol and 30.8% for control). Mean arterial pressure and heart rate increased after intubation in all groups but the changes were greater in the control groups than the esmolol groups. In conclusion, a single dose of esmolol blunted the increase in BIS to tracheal intubation during sevoflurane but not desflurane anesthesia.

  16. Microstructure and crystal growth direction of Al-Mg alloy

    Ti-jun Chen


    Full Text Available The microstructures and crystal growth directions of permanent mould casting and directionally solidified Al-Mg alloys with different Mg contents have been investigated. The results indicate that the effect of Mg content on microstructure is basically same for the alloys prepared by these two methods. The primary grains change from cellular crystals to developed columnar dendrites, and then to equiaxed dendrites as the Mg content is increased. Simultaneously, both the cellular or columnar grain region and the primary trunk spacing decrease. All of these changes are mainly attributed to the constitutional supercooling resulting from Mg element. Comparatively, the cellular or columnar crystals of the directionally solidified alloys are straighter and more parallel than those of the permanent mould casting alloys. These have straight or wavy grain boundaries, one of the most important microstructure characteristics of feathery grains. However, the transverse microstructure and growth direction reveal that they do not belong to feathery grains. The Mg seemingly can affect the crystal growth direction, but does not result in the formation of feathery grains under the conditions employed in the study.

  17. Mycorrhizal dependency of mangaba tree under increasing phosphorus levels Dependência micorrízica de mangabeira em doses crescentes de fósforo

    Júlio Alves Cardoso Filho


    Full Text Available The objective of this study was to evaluate the mycorrhizal dependency of mangaba tree (Hancornia speciosa plantlets, under increasing levels of phosphorus fertilization. The experimental design was completely randomized in a 4×5 factorial arrangement with three mycorrhizal fungi inocula - Gigaspora margarita, Glomus etunicatum, or a pool of native mycorrhizal fungi (Acaulospora longula, Glomus clarum, Gigaspora albida, Paraglomus sp. -, and a nonmycorrhizal control, in combination with five levels of phosphorus applied to the substrate: 0, 25, 50, 75, and 100 mg kg-1. After 180 days of growth, plantlets with inoculation of native mycorrhizal pool produced more shoot and root dry biomass and had higher shoot phosphorus content and accumulation. The noninoculated control showed the lowest values, independently of the phosphorus level. The highest relative mycorrhizal dependency occurred with the inoculation of native mycorrhizal fungi. Plants with mycorrhizal fungi did not respond to phosphorus addition above 50 mg kg-1. Mangaba tree is highly dependent on mycorrhiza, but the degree of dependency varies according to phosphorus levels and fungal inocula. In general, mangaba tree is more responsive to mycorrhizal fungi inoculation than to phosphorus addition.O objetivo deste trabalho foi avaliar a dependência micorrízica de mudas de mangaba (Hancornia speciosa, em doses crescentes de fósforo. O delineamento experimental foi inteiramente casualizado, em arranjo fatorial 4´5 com três inóculos de fungos micorrízicos - Gigaspora margarita, Glomus etunicatum, ou uma mistura de espécies de fungos micorrízicos nativos (Acaulospora longula, Glomus clarum, Gigaspora albida e Paraglomus sp. -, e um controle não micorrízico, combinados a cinco doses de fósforo no substrato: 0, 25, 50, 75 e 100 mg kg-1. Após 180 dias, as mudas com inoculação dos fungos micorrízicos nativos produziram mais biomassa seca de parte aérea e raízes e apresentaram

  18. Adsorption of atomic S and C on Mg(0001) surface

    HU Yu-lin; ZHANG Wei-bing; TANG Bi-yu; DING Wen-jiang; ZENG Xiao-qin


    First-principle calculations based on density functional theory were used to study the adsorption of atomic sulfur and carbon on the Mg(0001) surface in a wide range of coverages from 1/4 ML(monolayer) to 1 ML. It is found that the adsorption of atomic S and C on the high coordinate hollow site is more energetically favorable than that on other adsorption sites. S atom is favorable to be adsorbed at on-surface site and C atom is favorable to be adsorbed at subsurface site. The results suggest that when the coverage increases,the binding energy for S and C atoms will decrease and the interaction between adsorbed atoms tends to be stronger. It indicates that as coverage increases,S-Mg and C-Mg interaction weakens.

  19. Effect of organic ligands on Mg partitioning and Mg isotope fractionation during low-temperature precipitation of calcite

    Mavromatis, Vasileios; Immenhauser, Adrian; Buhl, Dieter; Purgstaller, Bettina; Baldermann, Andre; Dietzel, Martin


    Calcite growth experiments have been performed at 25 oC and 1 bar pCO2 in the presence of aqueous Mg and six organic ligands in the concentration range from 10-5 to 10-3 M. These experiments were performed in order to quantify the effect of distinct organic ligands on the Mg partitioning and Mg stable isotope fractionation during its incorporation in calcite at similar growth rates normalized to total surface area. The organic ligands used in this study comprise of (i) acetate acid, (ii) citrate, (iii) glutamate, (iv) salicylate, (v) glycine and (vi) ethylenediaminetetraacetic acid (EDTA), containing carboxyl- and amino-groups. These fuctional groups are required for bacterial activity and growth as well as related to biotic and abiotic mineralization processes occurring in sedimentary and earliest diagenetic aquatic environments (e.g. soil, cave, lacustrine, marine). The results obtained in this study indicate that the presence of organic ligands promotes an increase in the partition coefficient of Mg in calcite (DMg = (Mg/Ca)calcite (Mg/Ca)fluid). This behaviour can be explained by the temporal formation of aqueous Mg-ligand complexes that are subsequently adsorbed on the calcite surfaces and thereby reducing the active growth sites of calcite. The increase of DMg values as a function of the supersaturation degree of calcite in the fluid phase can be described by the linear equation LogDMg =0.3694 (±0.0329)×SIcalcite - 1.9066 (±0.0147); R2=0.92 In contrast, the presence of organic ligands, with exception of citrate, does not significantly affect the Mg isotope fractionation factor between calcite and reactive fluid (Δ26Mgcalcite-fluid = -2.5 ±0.1). Citrate likely exhibits larger fractionation between the Mg-ligand complexes and free aqueous Mg2+, compared to the other organic ligands studied in this work, as evidenced by the smaller Δ26Mgcalcite-fluid values. These results indicate that in Earth's surface calcite precipitating environments that are

  20. In-situ thermal analysis and macroscopical characterization of Mg-xCa and Mg-0.5Ca-xZn alloy systems

    Farahany, Saeed [Department of Materials Engineering, Faculty of Mechanical Engineering, Universiti Teknologi Malaysia, 81310 Johor Bahru, Johor (Malaysia); Bakhsheshi-Rad, Hamid Reza, E-mail: [Department of Materials Engineering, Faculty of Mechanical Engineering, Universiti Teknologi Malaysia, 81310 Johor Bahru, Johor (Malaysia); Idris, Mohd Hasbullah [Department of Materials Engineering, Faculty of Mechanical Engineering, Universiti Teknologi Malaysia, 81310 Johor Bahru, Johor (Malaysia); Abdul Kadir, Mohammed Rafiq [Medical Implants Technology Group, Universiti Teknologi Malaysia, 81310 Johor Bahru, Johor (Malaysia); Department of Biomechanics and Biomedical Materials, Faculty of Biomedical Engineering and Health Sciences, Universiti Teknologi Malaysia, 81310 Johor Bahru, Johor (Malaysia); Lotfabadi, Amir Fereidouni [Department of Manufacturing and Industrial Engineering, Faculty of Mechanical Engineering, Universiti Teknologi Malaysia, 81310 Johor Bahru, Johor (Malaysia); Ourdjini, Ali [Department of Materials Engineering, Faculty of Mechanical Engineering, Universiti Teknologi Malaysia, 81310 Johor Bahru, Johor (Malaysia)


    Highlights: Black-Right-Pointing-Pointer The effect of Ca and Zn addition on Mg-Ca and Mg-Ca-Zn were investigated. Black-Right-Pointing-Pointer Ca and Zn addition decreased solid fraction at coherency point. Black-Right-Pointing-Pointer T{sub N}-T{sub DCP} increased by adding Ca and Zn in Mg-Ca and Mg-Ca-Zn, respectively. Black-Right-Pointing-Pointer Three reactions were detected when Zn/Ca atomic ratio less than 1.25 in Mg-Ca-Zn. Black-Right-Pointing-Pointer A new peak Mg{sub 51}Zn{sub 20} was identified in Mg-0.5Ca-9Zn in addition of other peaks. - Abstract: This research described the identification phases by thermal analysis and microscopy inspection of Mg-xCa and Mg-0.5%Ca-xZn alloys that were solidified at slow cooling rate. Analysis of cooling curve after Ca addition shows the evolution of the Mg{sub 2}Ca intermetallic phase at around 520 Degree-Sign C in addition to {alpha}-Mg phase. First derivative curves of alloys after the addition of Zn to Mg-0.5Ca alloy reveals three peaks related to {alpha}-Mg, Mg{sub 2}Ca and Ca{sub 2}Mg{sub 6}Zn{sub 3} for alloys that have Zn/Ca atomic ratio less than 1.23. The peak of Mg{sub 2}Ca reaction on the first derivative curves disappeared for alloys containing Zn/Ca ratio more than 1.23. A new peak was also observed at 330 Degree-Sign C for Mg-0.5Ca-9Zn which was identified as Mg{sub 51}Zn{sub 20}. Solid fraction at coherency point decreased with increasing Ca and Zn elements. However, coherency time and difference between the nucleation and coherency temperatures (T{sub N}-T{sub DCP}) increased by adding Ca and Zn in Mg-Ca and Mg-Ca-Zn systems.

  1. Acute pain induces an instant increase in natural killer cell cytotoxicity in humans and this response is abolished by local anaesthesia

    Greisen, J.; Hokland, Marianne; Grøfte, Thorbjørn


    to abdominal skin for 30 min to an intensity of 8 on a visual analogue scale (0-10). Next, the electric intensity profile was reproduced during local anaesthesia (mepivacaine 10 mg ml-1 s.c. to a total dose of 2.5 mg kg-1). NK cell cytotoxicity was measured using a 4-h 51Cr-release assay against K562 target...

  2. Loss of Endothelial Barrier in Marfan Mice (mgR/mgR Results in Severe Inflammation after Adenoviral Gene Therapy.

    Philipp Christian Seppelt

    Full Text Available Marfan syndrome is an autosomal dominant inherited disorder of connective tissue. The vascular complications of Marfan syndrome have the biggest impact on life expectancy. The aorta of Marfan patients reveals degradation of elastin layers caused by increased proteolytic activity of matrix metalloproteinases (MMPs. In this study we performed adenoviral gene transfer of human tissue inhibitor of matrix metalloproteinases-1 (hTIMP-1 in aortic grafts of fibrillin-1 deficient Marfan mice (mgR/mgR in order to reduce elastolysis.We performed heterotopic infrarenal transplantation of the thoracic aorta in female mice (n = 7 per group. Before implantation, mgR/mgR and wild-type aortas (WT, C57BL/6 were transduced ex vivo with an adenoviral vector coding for human TIMP-1 (Ad.hTIMP-1 or β-galactosidase (Ad.β-Gal. As control mgR/mgR and wild-type aortas received no gene therapy. Thirty days after surgery, overexpression of the transgene was assessed by immunohistochemistry (IHC and collagen in situ zymography. Histologic staining was performed to investigate inflammation, the neointimal index (NI, and elastin breaks. Endothelial barrier function of native not virus-exposed aortas was evaluated by perfusion of fluorescent albumin and examinations of virus-exposed tissue were performed by transmission electron microscopy (TEM.IHC and ISZ revealed sufficient expression of the transgene. Severe cellular inflammation and intima hyperplasia were seen only in adenovirus treated mgR/mgR aortas (Ad.β-Gal, Ad.hTIMP-1 NI: 0.23; 0.43, but not in native and Ad.hTIMP-1 treated WT (NI: 0.01; 0.00. Compared to native mgR/mgR and Ad.hTIMP-1 treated WT aorta, the NI is highly significant greater in Ad.hTIMP-1 transduced mgR/mgR aorta (p = 0.001; p = 0.001. As expected, untreated Marfan grafts showed significant more elastolysis compared to WT (p = 0.001. However, elastolysis in Marfan aortas was not reduced by adenoviral overexpression of hTIMP-1 (compared to untreated

  3. Multilayer Mg-Stainless Steel Sheets, Twinning and Texture Evolution

    Inoue, Junya; Sadeghi, Alireza; Ohmori, Toshinori; Koseki, Toshihiko


    In the present study, different combinations of multilayer sheets were prepared from 1 and 2 mm Mg AZ31 along with 0.25, 0.5, and 1 mm 304 L stainless steel. The texture and microstructure of the elongated samples (20 and 30 pct strain) were studied. It was found that the transversal stress plays an important role in both texture evolution and twinning in these composites. The obtained pole figures revealed an axial texture tilt with increasing steel layer volume fraction ( V f). It was found that this is a direct effect of transverse stress, which becomes more significant upon reducing Mg V f. This extra stress component tilts the basal planes away from the original normal direction in monolithic samples. Moreover, our results indicate that with decreasing Mg V f, twinning activity was increased in the 20 pct deformed samples but reduced in the samples with 30 pct elongation. It is known that at high strains where sufficient transverse stress is generated, the activity of prismatic slip is significantly enhanced, which promotes the motion of dislocations and reduces the necessity of twinning. With decreasing Mg V f, stronger transversal stress is generated and Mg reaches the critical threshold of prismatic activity at lower strains.

  4. A randomized comparison of daunorubicin 90 mg/m2 vs 60 mg/m2 in AML induction

    Burnett, A. K.; Russell, N. H.; Hills, R. K.


    remission rate (73% vs 75%; odds ratio, 1.07 [0.83-1.39]; P = .6) or in any recognized subgroup. The 60-day mortality was increased in the 90 mg/m(2) arm (10% vs 5% (hazard ratio [HR] 1.98 [1.30-3.02]; P = .001), which resulted in no difference in overall 2-year survival (59% vs 60%; HR, 1.16 [0.95-1.43]; P...... recommended as a standard of care. However, 60 mg/m(2) is widely used and has never been directly compared with 90 mg/m(2). As part of the UK National Cancer Research Institute (NCRI) AML17 trial, 1206 adults with untreated AML or high-risk myelodysplastic syndrome, mostly younger than 60 years of age, were...... randomized to a first-induction course of chemotherapy, which delivered either 90 mg/m(2) or 60 mg/m(2) on days 1, 3, and 5 combined with cytosine arabinoside. All patients then received a second course that included daunorubicin 50 mg/m(2) on days 1, 3, and 5. There was no overall difference in complete...

  5. [Effects of exogenous iron on lead accumulation in Typha latifolia from a lead-contaminated soil].

    Zhong, Shun-Qing; Xu, Jian-Ming


    A pot experiment was conducted to study the effects of adding 100 and 500 mg x kg(-1) of exogenous iron (Fe) on the lead (Pb) accumulation in Typha latifolia growing on a soil with 0, 100, 500 and 1000 mg x kg(-1) of Pb, respectively. In treatment 500 mg Fe x kg(-1), the Pb concen tration in T. latifolia shoots and roots was higher, compared with that in treatment 100 mg Fe x kg(-1). When the soil Pb concentration was 1000 mg x kg(-1), the Pb concentration in T. lati folia shoots and roots in treatment 500 mg Fe x kg(-1) increased by 33.7% and 50.5%, respectively, compared with that in treatment 100 mg Fe x kg(-1). The exchangeable Pb concentration in rhizosphere soil was 77.0% -114.6% higher in treatment 500 mg Fe x kg(-1) than in treatment 100 mg Fe x kg(-1). When the soil Pb concentration was 0, 100 and 1000 mg x kg(-1), the root dry mass in treatment 500 mg Fe x kg(-1) had a significant decrease, compared with that in treatment 100 mg Fe x kg(-1). It was suggested that adding appropriate amount of Fe to Pb-contaminated wetland soil could increase the availability of soil Pb and improve the Pb accumulation in plants.

  6. Melatonin administration in diabetes: regulation of plasma Cr, V, and Mg in young male Zucker diabetic fatty rats.

    Navarro-Alarcon, Miguel; Ruiz-Ojeda, Francisco J; Blanca-Herrera, Rosa M; Kaki, Abdullah; Adem, Abdu; Agil, Ahmad


    The use of melatonin, a neurohormone present in plants, represents an exciting approach for the maintenance of optimum health conditions. Melatonin administration ameliorates glucose homeostasis in Zucker diabetic fatty (ZDF) rats. The objective of this study was to investigate the effects of melatonin in diabetes in relation to the levels and regulation of plasma chromium (Cr), vanadium (V), and magnesium (Mg) in Zucker diabetic fatty (ZDF) and Zucker lean (ZL) rats. At the age of 6 weeks, ZDF (n = 30) and ZL (n = 30) groups were each subdivided into three groups: control (C) (n = 10), vehicle-treated (V') (n = 10) and melatonin-treated (M) (10 mg kg(-1) per day; n = 10) groups for a 6 week period. After treatment, plasma mineral concentrations were measured by flame (Mg) and electrothermal (Cr and V) atomic absorption spectrometry. No significant differences were found between the C and V' groups (p > 0.05). Plasma Mg levels were significantly lower in C-ZDF vs. C-ZL rats, demonstrating the presence of hypomagnesemia in this diabetes mellitus model. Plasma V and Cr levels were significantly higher in M-ZDF vs. C-ZDF rats. Plasma Mg levels in ZDF rats were not affected by melatonin treatment (p > 0.05). Melatonin administration ameliorates the diabetic status of ZDF rats by enhancing plasma Cr and V concentrations. This appears to be the first report of a beneficial effect of melatonin treatment on plasma Cr and V regulation in ZDF rats.

  7. Theoretical simulation of CO2 capture by an \\text{A}{{\\text{l}}_{11}}\\text{Mg}_{3}^{-} cluster

    Jiang, Yuanyuan; Xie, Xuefang; Hamid, Ilyar; Chen, Chu; Duan, Haiming


    In order to have an impact on carbon emissions, new stable materials for carbon capture should be able to adsorb CO2 from a mixture of other gases efficiently. Based on density functional theory calculations, we showed that the \\text{A}{{\\text{l}}11}\\text{Mg}3- cluster has an excellent capture capacity of CO2 and high CO2 selectivity under ambient conditions. \\text{A}{{\\text{l}}11}\\text{Mg}3- has an O2-resist property because this cluster is similar to \\text{Al}13- which contains 40 electrons with a larger energy gap. The \\text{A}{{\\text{l}}11}\\text{Mg}3- cluster prefers to adsorb CO2 compared with CH4, H2 and N2, and the CO2 molecule can be chemically adsorbed on the cluster by overcoming a lower barrier, which originates from the introduction of the Mg atom. When seven CO2 molecules are chemically adsorbed on the cluster, the capture capacity of CO2 can reach up to 18.99 mol kg-1 this means that the \\text{A}{{\\text{l}}11}\\text{Mg}3- cluster can be viewed as a potential candidate material for CO2 capture.

  8. UHV and Ambient Pressure XPS: Potentials for Mg, MgO, and Mg(OH)2 Surface Analysis

    Head, Ashley R.; Schnadt, Joachim


    The surface sensitivity of x-ray photoelectron spectroscopy (XPS) has positioned the technique as a routine analysis tool for chemical and electronic structure information. Samples ranging from ideal model systems to industrial materials can be analyzed. Instrumentational developments in the past two decades have popularized ambient pressure XPS, with pressures in the tens of mbar now commonplace. Here, we briefly review the technique, including a discussion of developments that allow data collection at higher pressures. We illustrate the information XPS can provide by using examples from the literature, including MgO studies. We hope to illustrate the possibilities of ambient pressure XPS to Mg, MgO, and Mg(OH)2 systems, both in fundamental and applied studies.

  9. Diffusion of Ca and Mg in Calcite

    Cygan, R.T.; Fisler, D.K.


    The self-diffusion of Ca and the tracer diffusion of Mg in calcite have been experimentally measured using isotopic tracers of {sup 25}Mg and {sup 44}Ca. Natural single crystals of calcite were coated with a thermally-sputtered oxide thin film and then annealed in a CO{sub 2} gas at one atmosphere total pressure and temperatures from 550 to 800 C. Diffusion coefficient values were derived from the depth profiles obtained by ion microprobe analysis. The resultant activation energies for Mg tracer diffusion and Ca self-diffusion are respectively: E{sub a}(Mg) = 284 {+-} 74 kJ/mol and E{sub a}(Ca) = 271 {+-} 80 kJ/mol. For the temperature ranges in these experiments, the diffusion of Mg is faster than Ca. The results are generally consistent in magnitude with divalent cation diffusion rates obtained in previous studies and provide a means of interpreting the thermal histories of carbonate minerals, the mechanism of dolomitization, and other diffusion-controlled processes. The results indicate that cation diffusion in calcite is relatively slow and cations are the rate-limiting diffusing species for the deformation of calcite and carbonate rocks. Application of the calcite-dolomite geothermometer to metamorphic assemblages will be constrained by cation diffusion and cooling rates. The direct measurement of Mg tracer diffusion in calcite indicates that dolomitization is unlikely to be accomplished by Mg diffusion in the solid state but by a recrystallization process.

  10. Treatment of patients with essential hypertension: amlodipine 5 mg/benazepril 20 mg compared with amlodipine 5 mg, benazepril 20 mg, and placebo.

    Kuschnir, E; Acuña, E; Sevilla, D; Vasquez, J; Bendersky, M; Resk, J; Glazer, R


    This multicenter, double-masked, randomized, parallel-group study compared the efficacy, tolerability, and safety of amlodipine 5 mg/benazepril 20 mg, amlodipine 5 mg, benazepril 20 mg, and placebo in patients with essential hypertension. After a placebo run-in period, 308 patients (all white) were randomized to treatment groups and took medication once daily for 8 weeks. Blood pressure was measured after 4 and 8 weeks of treatment in the 23- to 26-hour period after dosing. Patients wore a noninvasive blood pressure monitor for 24 hours before randomization and before the final visit. Investigators recorded adverse experiences at randomization and at study weeks 4 and 8, and obtained specimens for laboratory testing at randomization and at study week 8. Three hundred seven patients were evaluated for efficacy, and 308 for tolerability and safety. At end point (the last postrandomization measurement for each patient), the reduction in mean sitting diastolic blood pressure with the amlodipine 5 mg/benazepril 20 mg treatment was statistically significantly greater than with any comparative therapy. The results of 24-hour monitoring showed that the amlodipine/benazepril treatment, unlike monotherapy, maintained the hourly mean diastolic blood pressure at amlodipine 5 mg/benazepril 20 mg versus 67.5%, 53.3%, and 15.8% with amlodipine, benazepril, and placebo, respectively. This difference between the amlodipine/benazepril treatment group and each comparative single-agent treatment group was statistically significant. Drug-related adverse events occurred in 15.6% of patients in the amlodipine/benazepril group and in 24.7%, 6.5%, and 11.7% of patients in the amlodipine, benazepril, and placebo groups, respectively. Edema occurred less often in the amlodipine/benazepril group than in the amlodipine group. Overall, once-daily therapy with amlodipine 5 mg/benazepril 20 mg provided an antihypertensive effect that was statistically and clinically superior to amlodipine 5 mg

  11. Solvation of Mg in Helium-4: Are there Meta-stable Mg Dimers ?

    Krotscheck, Eckhard


    Experiments on the formation of magnesium complexes in $^4$He nanodroplets were interpreted as the observation of the formation of weakly bound magnesium complexes. We present results for single Mg and Mg dimer solvation using the hypernetted chain / Euler-Lagrange method as well as path integral Monte Carlo simulations. We find that the phonon-mediated, indirect Mg-Mg interaction adds an oscillatory component to the direct Mg-Mg interaction. We undertake a step-by-step examination of the ingredients of the calculation of the phonon-induced interaction, comparing the results of semi-analytic HNC-EL calculations for bulk and single impurity results with experiments as well as Monte Carlo data. We do not find evidence for a sufficiently strong secondary minimum in the effective Mg-Mg interaction to support a metastable state.

  12. Natural ageing responses of duplex structured Mg-Li based alloys

    Li, C. Q.; Xu, D. K.; Wang, B. J.; Sheng, L. Y.; Qiao, Y. X.; Han, E. H.


    Natural ageing responses of duplex structured Mg-6%Li and Mg-6%Li-6%Zn-1.2%Y alloys have been investigated. Microstructural analyses revealed that the precipitation and coarsening process of α-Mg particles could occur in β-Li phases of both two alloys during ageing process. Since a certain amount of Mg atoms in β-Li phases were consumed for the precipitation of abundant tiny MgLiZn particles, the size of α-Mg precipitates in Mg-6%Li-6%Zn-1.2%Y alloy was relatively smaller than that in Mg-6%Li alloy. Micro hardness measurements demonstrated that with the ageing time increasing, the α-Mg phases in Mg-6%Li alloy could have a constant hardness value of 41 HV, but the contained β-Li phases exhibited a slight age-softening response. Compared with the Mg-6%Li alloy, the age-softening response of β-Li phases in Mg-6%Li-6%Zn-1.2%Y alloy was much more profound. Meanwhile, a normal age-hardening response of α-Mg phases was maintained. Tensile results indicated that obvious ageing-softening phenomenon in terms of macro tensile strength occurred in both two alloys. Failure analysis demonstrated that for the Mg-6%Li alloy, cracks were preferentially initiated at α-Mg/β-Li interfaces. For the Mg-6%Li-6%Zn-1.2%Y alloy, cracks occurred at both α-Mg/β-Li interfaces and slip bands in α-Mg and β-Li phases.

  13. In vitro degradation and cytotoxicity of Mg/Ca composites produced by powder metallurgy.

    Zheng, Y F; Gu, X N; Xi, Y L; Chai, D L


    Mg/Ca (1 wt.%, 5 wt.%, 10 wt.% Ca) composites were prepared from pure magnesium and calcium powders using the powder metallurgy method, aiming to enlarge the addition of Ca content without the formation of Mg(2)Ca. The microstructures, mechanical properties and cytotoxicities of Mg/Ca composite samples were investigated. The corrosion of Mg/Ca composites in Dulbecco's modified Eagle's medium (DMEM) for various immersion intervals was studied by electrochemical impedance spectroscopy measurements and environmental scanning electron microscope, with the concentrations of released Mg and Ca ions in DMEM for various immersion time intervals being measured. It was shown that the main constitutional phases were Mg and Ca, which were uniformly distributed in the Mg matrix. The ultimate tensile strength (UTS) and elongation of experimental composites decreased with increasing Ca content, and the UTS of Mg/1Ca composite was comparable with that of as-extruded Mg-1Ca alloy. The corrosion potential increased with increasing Ca content, whereas the current density and the impedance decreased. It was found that the protective surface film formed quickly at the initial immersion stage. With increasing immersion time, the surface film became compact, and the corrosion rate of Mg/Ca composites slowed down. The surface film consisted mainly of CaCO(3), MgCO(3)x3H(2)O, HA and Mg(OH)(2) after 72 h immersion in DMEM. Mg/1Ca and Mg/5Ca composite extracts had no significant toxicity (p>0.05) to L-929 cells, whereas Mg/10Ca composite extract induced approximately 40% reduced cell viability.

  14. Superconductivity in MgB2 irradiated with energetic protons

    Sandu, Viorel; Craciun, Liviu; Ionescu, Alina Marinela; Aldica, Gheorghe; Miu, Lucica; Kuncser, Andrei


    A series of MgB2 samples were irradiated with protons of 11.3 and 13.2 MeV. Magnetization data shows an insignificant reduction of the critical temperatures but a continuous decrease of the Meissner fraction with increasing fluence or energy. All samples show a consistent improvement of the critical current density compared to the virgin sample and an increase of the pinning energy at high fields as resulted from relaxation data.

  15. Methylglyoxal (MG) and cerebro-renal interaction: does long-term orally administered MG cause cognitive impairment in normal Sprague-Dawley rats?

    Watanabe, Kimio; Okada, Kana; Fukabori, Ryoji; Hayashi, Yoshimitsu; Asahi, Koichi; Terawaki, Hiroyuki; Kobayashi, Kazuto; Watanabe, Tsuyoshi; Nakayama, Masaaki


    Methylglyoxal (MG), one of the uremic toxins, is a highly reactive alpha-dicarbonyl compound. Recent clinical studies have demonstrated the close associations of cognitive impairment (CI) with plasma MG levels and presence of kidney dysfunction. Therefore, the present study aims to examine whether MG is a direct causative substance for CI development. Eight-week-old male Sprague-Dawley (SD) rats were divided into two groups: control (n = 9) and MG group (n = 10; 0.5% MG in drinking water), and fed a normal diet for 12 months. Cognitive function was evaluated by two behavioral tests (object exploration test and radial-arm maze test) in early (4-6 months of age) and late phase (7-12 months of age). Serum MG was significantly elevated in the MG group (495.8 ± 38.1 vs. 244.8 ± 28.2 nM; p < 0.001) at the end of study. The groups did not differ in cognitive function during the course of study. No time-course differences were found in oxidative stress markers between the two groups, while, antioxidants such as glutathione peroxidase and superoxide dismutase activities were significantly increased in the MG group compared to the control. Long-term MG administration to rats with normal kidney function did not cause CI. A counter-balanced activation of the systemic anti-oxidant system may offset the toxicity of MG in this model. Pathogenetic significance of MG for CI requires further investigation.

  16. Aging Behavior of Mg-Y-Zr and Mg-Nd-Zr Cast Alloys


    Aging behavior of Mg-3.6Y-0.5Zr and Mg-2.7Nd-0.5Zr alloys was investigated by microhardness measurement and transmission electron microscopy. In the case of Mg-Y-Zr alloy, the presence of β″ phase, a major strengthener, having base centered orthorhombic structure with its lattice constants of aβ″=0.64 nm, bβ″=2.22 nm,and cβ″=0.52 nm was identified. In the case of Mg-Nd-Zr alloy aged at 250℃, the presence ofβ″ and β′phases was identified. The crystal structure ofβ″ phase was found to be DO19 and its orientation relationships with Mg matrix were [0001]β″//[0001]Mg and [01-10]β″//[0110]Mg. The β′ phase had face centered cubicstructure and its orientation relationships with Mg matrix were [011]β′//[0001]Mg and [-11-1]β′//[-2110]Mg.The Mg-2.7Nd-0.5Zr alloy showed higher hardness compared with Mg-3.6Y-0.5Zr alloy.

  17. In vitro and in vivo comparison of binary Mg alloys and pure Mg.

    Myrissa, Anastasia; Agha, Nezha Ahmad; Lu, Yiyi; Martinelli, Elisabeth; Eichler, Johannes; Szakács, Gábor; Kleinhans, Claudia; Willumeit-Römer, Regine; Schäfer, Ute; Weinberg, Annelie-Martina


    Biodegradable materials are under investigation due to their promising properties for biomedical applications as implant material. In the present study, two binary magnesium (Mg) alloys (Mg2Ag and Mg10Gd) and pure Mg (99.99%) were used in order to compare the degradation performance of the materials in in vitro to in vivo conditions. In vitro analysis of cell distribution and viability was performed on discs of pure Mg, Mg2Ag and Mg10Gd. The results verified viable pre-osteoblast cells on all three alloys and no obvious toxic effect within the first two weeks. The degradation rates in in vitro and in vivo conditions (Sprague-Dawley® rats) showed that the degradation rates differ especially in the 1st week of the experiments. While in vitro Mg2Ag displayed the fastest degradation rate, in vivo, Mg10Gd revealed the highest degradation rate. After four weeks of in vitro immersion tests, the degradation rate of Mg2Ag was significantly reduced and approached the values of pure Mg and Mg10Gd. Interestingly, after 4 weeks the estimated in vitro degradation rates approximate in vivo values. Our systematic experiment indicates that a correlation between in vitro and in vivo observations still has some limitations that have to be considered in order to perform representative in vitro experiments that display the in vivo situation.

  18. Thermodynamic optimization of Mg-Nd system

    MENG Fan-gui; LIU Hua-shan; LIU Li-bin; JIN Zhan-peng


    Based on the reported experimental data, the phase diagram of Mg-Nd binary system was optimized using the CALPHAD approach. Gibbs energies of the disordered BCC_A2 and ordered BCC_B2 phases were modeled with a single expression based on a 2-sublattice model. Liquid and terminal solutions, such as dHCP and HCP, were modeled as substitutional solutions. Intermediate phases Mg2Nd, Mg3Nd and Mg41Nd5 were treated as stoichiometric compounds. The optimization was carried out in the Thermo-Calc package. A set of thermodynamic parameters is obtained. Calculated phase diagram, enthalpies of formation and Gibbs energies of formation are in reasonable agreement with the experimental data.

  19. The MG-RAST metagenomics database and portal in 2015.

    Wilke, Andreas; Bischof, Jared; Gerlach, Wolfgang; Glass, Elizabeth; Harrison, Travis; Keegan, Kevin P; Paczian, Tobias; Trimble, William L; Bagchi, Saurabh; Grama, Ananth; Chaterji, Somali; Meyer, Folker


    MG-RAST ( is an open-submission data portal for processing, analyzing, sharing and disseminating metagenomic datasets. The system currently hosts over 200,000 datasets and is continuously updated. The volume of submissions has increased 4-fold over the past 24 months, now averaging 4 terabasepairs per month. In addition to several new features, we report changes to the analysis workflow and the technologies used to scale the pipeline up to the required throughput levels. To show possible uses for the data from MG-RAST, we present several examples integrating data and analyses from MG-RAST into popular third-party analysis tools or sequence alignment tools.

  20. Biodegradability engineering of biodegradable Mg alloys: Tailoring the electrochemical properties and microstructure of constituent phases

    Cha, Pil-Ryung; Han, Hyung-Seop; Yang, Gui-Fu; Kim, Yu-Chan; Hong, Ki-Ha; Lee, Seung-Cheol; Jung, Jae-Young; Ahn, Jae-Pyeong; Kim, Young-Yul; Cho, Sung-Youn; Byun, Ji Young; Lee, Kang-Sik; Yang, Seok-Jo; Seok, Hyun-Kwang


    Crystalline Mg-based alloys with a distinct reduction in hydrogen evolution were prepared through both electrochemical and microstructural engineering of the constituent phases. The addition of Zn to Mg-Ca alloy modified the corrosion potentials of two constituent phases (Mg + Mg2Ca), which prevented the formation of a galvanic circuit and achieved a comparable corrosion rate to high purity Mg. Furthermore, effective grain refinement induced by the extrusion allowed the achievement of much lower corrosion rate than high purity Mg. Animal studies confirmed the large reduction in hydrogen evolution and revealed good tissue compatibility with increased bone deposition around the newly developed Mg alloy implants. Thus, high strength Mg-Ca-Zn alloys with medically acceptable corrosion rate were developed and showed great potential for use in a new generation of biodegradable implants.

  1. Multifunctional MgO Layer in Perovskite Solar Cells.

    Guo, Xudong; Dong, Haopeng; Li, Wenzhe; Li, Nan; Wang, Liduo


    A multifunctional magnesium oxide (MgO) layer was successfully introduced into perovskite solar cells (PSCs) to enhance their performance. MgO was coated onto the surface of mesoporous TiO(2) by the decomposition of magnesium acetate and, therefore, could block contact between the perovskite and TiO(2). X-ray photoelectron spectroscopy and infrared spectroscopy showed that the amount of H(2)O/hydroxyl absorbed on the TiO(2) decreased after MgO modification. The UV/Vis absorption spectra of the perovskite with MgO modification revealed an enhanced photoelectric performance compared with that of unmodified perovskite after UV illumination. In addition to the photocurrent, the photovoltage and fill factor also showed an enhancement after modification, which resulted in an increase in the overall efficiency of the cell from 9.6 to 13.9 %. Electrochemical impedance spectroscopy (EIS) confirmed that MgO acts as an insulating layer to reduce charge recombination.

  2. Stoichiometric carbon substitution in MgB{sub 2}

    Balaselvi, S Jemima; Gayathri, N; Bharathi, A; Sastry, V S; Hariharan, Y [Materials Science Division, Indira Gandhi Centre for Atomic Research, Kalpakkam 603102 (India)


    Carbon has been substituted into the MgB{sub 2} lattice, forming the series Mg(B{sub 1-x}C{sub x}){sub 2}, by heat treatments in sealed Ta tubes starting with elemental constituents. The superconducting transition temperature, T{sub C}, was measured by diamagnetic susceptibility. The superconducting transitions are sharp and the x-ray diffraction on the samples show only trace amounts of impurity phases. The C fraction that substitutes the B atoms into the MgB{sub 2} lattice, as determined from the now well established correlation between the 'a' lattice parameter and x in Mg(B{sub 1-x}C{sub x}){sub 2} is found to be very close to the targeted values. The temperature dependence of the normalized resistance is similar to that seen in C doped MgB{sub 2} single crystals along the ab plane. R{sub n}/R(300 K), where R{sub n} is the resistance just above T{sub C}, increases with x.

  3. Formation of MgZnO alloy under thermodynamic conditions

    Markevich, I.V.; Stara, T.R., E-mail:; Kuchuk, A.V.; Polishchuk, Yu.O.; Kladko, V.P.


    Mg{sub x}Zn{sub 1−x}O ceramics with x=0.10, 0.15, 0.20, 0.25 and 0.30 were sintered at T{sub s}=700–1250 °C. Photoluminescence (PL) and PL excitation (PLE) spectra as well as X-ray diffraction patterns were measured at 293 K. Bandgap width was evaluated from the position of PLE peak. Non-monotonous dependence of PLE peak position on T{sub s} was observed for all used x. This effect was concluded to be caused by the formation of cubic phase side by side with hexagonal one and the enhancement of this process with increasing T{sub s}, which resulted in the decrease of Mg content in the hexagonal phase at T{sub s}>1000 °C. Temperature range of 1000–1050 °C was found to be the optimum one for the formation of hexagonal MgZnO alloy at used x. It was shown that x=0.20 was the solubility limit of MgO in hexagonal Mg{sub x}Zn{sub 1−x}O ceramics.

  4. Quaternary BeMgZnO by plasma-enhanced molecular beam epitaxy for BeMgZnO/ZnO heterostructure devices

    Ullah, M. B.; Toporkov, M.; Avrutin, V.; Özgür, Ü.; Smith, D. J.; Morkoç, H.


    We investigated the crystal structure, growth kinetics and electrical properties of BeMgZnO/ZnO heterostructures grown by Molecular Beam Epitaxy (MBE). Transmission Electron Microscopy (TEM) studies revealed that incorporation of Mg into the BeZnO solid solution eliminates the high angle grain boundaries that are the major structural defects in ternary BeZnO. The significant improvement of x-ray diffraction intensity from quaternary BeMgZnO alloy compared to ternary BeZnO was attributed to the reduction of lattice strain, which is present in the latter due to the large difference of covalent radii between Be and Zn (1.22 Å for Zn, 0.96 Å for Be). Incorporation of Mg, which has a larger covalent radius of 1.41Å, reduced the strain in BeMgZnO thin films and also enhanced Be incorporation on lattice sites in the wurtzite lattice. The Zn/(Be + Mg) ratio necessary to obtain single-crystal O-polar BeMgZnO on (0001) GaN/sapphire templates was found to increase with increasing substrate temperature:3.9, 6.2, and 8.3 at substrate temperatures of 450°C, 475°C, and 500°C, respectively. Based on analysis of photoluminescence spectra from Be0.03MgyZn0.97-yO and evolution of reflection high-energy electron diffraction patterns observed in situ during the MBE growth, it has been deduced that more negative formation enthalpy of MgO compared to ZnO and the increased surface mobility of Mg adatoms at elevated substrate temperatures give rise to the nucleation of a MgO-rich wurtzite phase at relatively low Zn/(Be + Mg) ratios. We have demonstrated both theoretically and experimentally that the incorporation of Be into the barrier in Zn-polar BeMgZnO/ZnO and O-polar ZnO/BeMgZnO polarization doped heterostructures allows the alignment of piezoelectric polarization vector with that of spontaneous polarization due to the change of strain sign, thus increasing the amount of net polarization. This made it possible to achieve Zn-polar BeMgZnO/ZnO heterostructures grown on Ga

  5. Increased lipid peroxidation in trained men after 2 weeks of antioxidant supplementation.

    Lamprecht, Manfred; Hofmann, Peter; Greilberger, Joachim F; Schwaberger, Guenther


    To assess the effects of an encapsulated antioxidant concentrate (EAC) and exercise on lipid peroxidation (LIPOX) and the plasma antioxidant enzyme glutathione peroxidase (Pl-GPx). Eight trained male cyclists (VO2max > 55 ml x kg(-1) x min(-1)) participated in this randomized, placebo-controlled, double-blinded, crossover study and undertook 4 cycle-ergometer bouts: 2 moderate exercise bouts over 90 min at 45% of individual VO2max and 2 strenuous exercise bouts at 75% of individual VO2max for 30 min. The first 2 exercise tests--1 moderate and 1 strenuous-were conducted after 4 weeks wash-out and after 12 and 14 days of EAC (107 IU vitamin E, 450 mg vitamin C, 36 mg beta-carotene, 100 microg selenium) or placebo treatment. After another 4 weeks wash-out, participants were given the opposite capsule treatment and repeated the 2 exercise tests. Physical exercise training was equal across the whole study period, and nutrition was standardized by a menu plan the week before the tests. Blood was collected before exercise, immediately postexercise, and 30 min and 60 min after each test. Plasma samples were analyzed for LIPOX marker malondialdehyde (MDA) and the antioxidant enzyme pl-GPx. MDA concentrations were significantly increased after EAC supplementation at rest before exercise and after moderate exercise (p .1). Pl-GPx concentrations decreased at all time points of measurement after EAC treatment (p < .05). The EAC induced an increase of LIPOX as indicated by MDA and decreased pl-GPx concentrations pre- and postexercise.

  6. Fabrication of the p-MgZnO/ZnO/n-MgZnO double-heterojunction by MOCVD

    Dong Xin; Wang Hui; Wang Jin; Zhao Wang; Zhao Long; Shi Zhifeng, E-mail: [State Key Laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, Qianjin Street 2699, ChangChun 130012 (China)


    The p-MgZnO/i-ZnO/n-MgZnO double-heterojuntion was fabricated on GaAs (100) substrate by photon-assistant metal-organic chemical vapor deposition. We can found an obvious ultraviolet peak in the electroluminescence spectra and the causation has been discussed. The effects of the thickness of ZnO interlayer on the junctions properties was also analyzed. The conclusion indicated the intensity of the UV peak would increase by decreasing the thickness of ZnO interlayer. The thickness of ZnO layer had important impact on the optical qualities of the double-heterojunction.

  7. Qualidade de ovos, parâmetros bioquímicos sanguíneos e desenvolvimento do aparelho reprodutor de poedeiras comerciais Lohmann LSL alimentadas com níveis crescentes de lisina digestível - DOI: 10.4025/actascianimsci.v30i1.3596 Egg quality, blood biochemical parameters and reproductive tract development for Lohmann LSL hens fed increasing levels of digestible lysine - DOI: 10.4025/actascianimsci.v30i1.3596

    Anúzia Barini Nunes


    Full Text Available O objetivo deste trabalho foi avaliar os efeitos de lisina para poedeiras Lohmann LSL sobre a qualidade dos ovos, parâmetros bioquímicos sanguíneos e mensurações do aparelho reprodutor. Cento e sessenta poedeiras com 24 semanas foram submetidas a níveis crescentes de lisina digestível (600, 700, 800 e 900 mg Lys kg-1 de ração até 48 semanas de idade. As dietas foram isoenergéticas e isonutritivas com 15,8%PB e 2.800 kcal EM kg-1. Delineamento inteiramente casualizado foi adotado com quatro tratamentos e quatro repetições. Foram analisados: percentagem de casca, de gema e albúmen, gravidade específica dos ovos, unidade Haugh, índice gema, sólidos totais da gema, do albúmen e do ovo, parâmetros sanguíneos e mensuração do aparelho reprodutor. Os resultados foram submetidos à análise de variância e de regressão polinomial (5%, utilizando o programa SAS, e para os resultados sanguíneos e do aparelho reprodutor, foram analisados em esquema de parcelas subdivididas. Os níveis de lisina não influenciaram os resultados para qualidade dos ovos. Houve aumento no peso do aparelho reprodutor com o avançar da idade. Os resultados do parâmetro sanguíneo não foram influenciados; já nas semanas, observa-se aumento na albumina, uratos e uratina. O nível de 600 mg kg-1 pode ser recomendado para poedeiras no período avaliado.In this experiment, the effect of lysine levels on egg quality, biochemical parameters and measurements of the reproductive tract on the diets of Lohmann LSL laying hens diets were evaluated. One hundred-sixty hens with 24 weeks of age were submitted to increasing levels of digestible lysine (600, 700, 800 e 900 mg Lys kg-1 of feed until 48 weeks of age. The diets were isoenergetic and isonutritive. A completely randomized design was used, with four treatments and four replicates. Percentages of eggshell, yolk and albumen, specific egg gravity, yolk index, total yolk, albumen and egg solids, blood parameters

  8. Change of Electronic Structure and Magnetic Properties with MgO and Fe Thicknesses in Fe/MgO/Fe Magnetic Tunnel Junction

    YANG Fan; BI Xiao-fang


    The effects of the thickness of MgO and Fe on the electronic structure and magnetic properties of Fe/MgO/Fe magnetic tunnel junction was studied using the first principle method. Two series of models with MgO of different thicknesses: Fe(3)MgO(t)Fe(3) (t=1,3,5,7) and with Fe of varied thicknesses: Fe(t)MgO(3)Fe(t) (t=3,4,5,6,7) were established. Calculated results show that in all the models the magnetic moment of Fe increases at the Fe/MgO interface and surface as compared with that of the inner layers. The magnetic moment of each Fe layer was found to be independent of MgO thicknesses, while the spin-polarization of Fe layer at the interface shows a slight change in function of the MgO thicknesses. The tunneling magnetoresistance (TMR) ratio estimated by the Julliere model has the same change tendency as the spin-polarization has, and the largest value is obtained at the MgO thickness of 5 atomic layers. When the Fe thickness increases, the spin-polarization of interface Fe layer follows up an increase with a decrease. The highest TMR value is achieved when the Fe thickness is of 4 atomic layers.

  9. Uncaria tomentosa increases growth and immune activity in Oreochromis niloticus challenged with Streptococcus agalactiae.

    Yunis-Aguinaga, Jefferson; Claudiano, Gustavo S; Marcusso, Paulo F; Manrique, Wilson Gómez; de Moraes, Julieta R Engrácia; de Moraes, Flávio R; Fernandes, João B K


    Cat's claw (Uncaria tomentosa) is an Amazon herb using in native cultures in Peru. In mammals, it has been described several effects of this herb. However, this is the first report of its use on the diet of fish. The aim of this study was to determinate the effect of this plant on the growth and immune activity in Oreochromis niloticus. Nile tilapia (81.3 ± 4.5 g) were distributed into 5 groups and supplemented with 0 (non-supplement fish), 75, 150, 300, and 450 mg of U. of diet for a period of 28 days. Fish were inoculated in the swim bladder with inactivated Streptococcus agalactiae and samples were taken at 6, 24, and 48 h post inoculation (HPI). Dose dependent increases were noted in some of the evaluated times of thrombocytes and white blood cells counts (WBC) in blood and exudate, burst respiratory activity, lysozyme activity, melanomacrophage centers count (MMCs), villi length, IgM by immunohistochemistry in splenic tissue, and unexpectedly on growth parameters. However, dietary supplementation of this herb did not affect red blood cells count (RBC), hemoglobin, and there were no observed histological lesions in gills, intestine, spleen, and liver. The current results demonstrate for the first time that U. tomentosa can stimulate fish immunity and improve growth performance in Nile tilapia. Copyright © 2015 Elsevier Ltd. All rights reserved.

  10. Ambroxol suppresses influenza-virus proliferation in the mouse airway by increasing antiviral factor levels.

    Yang, B; Yao, D F; Ohuchi, M; Ide, M; Yano, M; Okumura, Y; Kido, H


    The protective effect of ambroxol, a mucolytic agent which has antioxidant properties and stimulates the release of pulmonary surfactant, against influenza-virus proliferation in the airway was investigated in mice. Ambroxol or the vehicle was administered intraperitoneally twice a day for 5-7 days to mice shortly after intranasal infection with a lethal dose of influenza A/Aichi/68 (H3N2) virus, and the survival rate, virus titre and levels of factors regulating virus proliferation in the airway fluid were analysed. Ambroxol significantly suppressed virus multiplication and improved the survival rate of mice. The effect of ambroxol reached a peak at 10 mg x kg(-1) x day(-1), higher doses being less effective. Ambroxol stimulated the release of suppressors of influenza-virus multiplication, such as pulmonary surfactant, mucus protease inhibitor, immunoglobulin (Ig)-A and IgG, although it stimulated the release of a trypsin-type protease that potentiates virus proliferation. In addition, ambroxol transiently suppressed release of the cytokines, tumour necrosis factor-alpha, interferon-gamma and interleukin-12, into airway fluid. Although ambroxol had several negative effects on the host defence system, overall it strikingly increased the concentrations of suppressors of influenza-virus multiplication in the airway.


    陈冬利; 王为忠; 王俊义


    Objective. To evaluate the effects of epidermal growth factor (EGF) on intestinal permeability and bacterial translocation in rats with acute pancreatitis during total parenteral nutrition (TPN). Methods. Thirty-two male Sprague-Dawley rats that underwent injection of 3.5% sodium taurocholate solution into the pancreatic duct were randomly divided into one of the following two groups: (1) received only TPN (control group) or (2) received TPN with EGF at a dose of 0.2 mg· kg-1· day-1 (Egf group). On fifth day of total parenteral nutrition, samples from mesenteric lymph nodes, pancreas, liver and spleen were harvested for cultures. Water, protein and DNA content in jejunal mucosa were determined. D-xylose and fluorescein isothiocyanate (FITC)-dextran were instilled into the lumen of a ligated segament of small intestine. Thirty minutes later, superior mesenteric vein D-xylose and plasma FITC-dextran concentration were measured. Results. Positive cultures in liver and spleen, as well as FITC-dextran concentration in the Egf group were significantly lower than in the control group. Protein and DNA content in jejunal mucosa in the Egf group were significantly higher than in the control group. Conclusion. The results indicate that EGF may prevent increased intestinal permeability and bacterial translocation in rats with acute pancreatitis during TPN.

  12. Yohimbine increases submaxillary kallikrein release into the saliva in dogs: evidence for alpha 2-adrenoceptor-mediated inhibition of cholinergic pathways.

    Girolami, J. P.; Bascands, J. L.; Pécher, C.; Berlan, M.; Montastruc, J. L.; Montastruc, P.


    1. The effects of the alpha 2-adrenoceptor antagonist, yohimbine (0.5 mg kg-1, i.v.) on basal, sympathetic and parasympathetic stimulation-induced submaxillary kallikrein release were investigated in the anaesthetized dog. Kallikrein was measured by its kininogenase activity before and after trypsin activation which also allowed a study of the proportion of active to total enzyme. 2. Yohimbine induced a rapid, three fold increase in basal kallikrein release correlated with an increase in salivary flow rate which lasted for 60 min following injection. 3. Sectioning the chorda tympani did not affect basal kallikrein release but abolished yohimbine-induced rise in salivary kallikrein secretion. 4. Parasympathetic stimulation alone induced a 3 to 4 fold increase in basal kallikrein release correlated with an increase in salivary flow rate. Yohimbine induced a significant additional increase in parasympathetic-stimulated kallikrein release. 5. When the cervical sympathetic nerve was sectioned the basal kallikrein release decreased by 30 to 40%. 6. Sympathetic stimulation alone also induced a 3 to 4 fold increase in basal kallikrein. This was not correlated with the salivary flow and unaffected by yohimbine. 7. The results indicate that yohimbine increases submaxillary kallikrein release into the saliva by inhibition of presynaptic alpha 2-adrenoceptors located on the chorda tympani nerve endings. PMID:1849766

  13. Different annealing temperature suitable for different Mg doped P-GaN

    Liu, S. T.; Yang, J.; Zhao, D. G.; Jiang, D. S.; Liang, F.; Chen, P.; Zhu, J. J.; Liu, Z. S.; Li, X.; Liu, W.; Zhang, L. Q.; Long, H.; Li, M.


    In this work, epitaxial GaN with different Mg doping concentration annealed at different temperature is investigated. Through Hall and PL spectra measurement we found that when Mg doping concentration is different, different annealing temperature is needed for obtaining the best p-type conduction of GaN, and this difference comes from the different influence of annealing on compensated donors. For ultra-heavily Mg doped sample, the process of Mg related donors transferring to non-radiative recombination centers is dominated, so the performance of P-GaN deteriorates with temperature increase. But for low Mg doped sample, the process of Mg related donors transfer to non-raditive recombination is weak compare to the Mg acceptor activation, so along the annealing temperature increase the performance GaN gets better.

  14. The influence of Mg-Zr master alloy microstructure on the corrosion of Mg

    Gandel, D. S.; Easton, M. A.; Gibson, M. A.; Abbott, T.; Birbilis, N.

    In this study, sixteen Mg-Zr alloys were produced to investigate the role of Zr on corrosion of Mg. Alloys were produced using two different commercial Mg-Zr master alloys commonly used for grain refining Mg, but which contain different Zr particle size distributions. It is seen that the master alloy with a smaller Zr particle size leads to an alloy containing more Zr in solid solution. The ratio of Zr in solid solution and in particle form was observed to have a marked effect on the corrosion of Mg.

  15. Features of Mg2Si Layer Growth in Si/Mg2Si Multilayers

    L.E. Konotopskyi


    Full Text Available Features of magnesium siliced layer growth in Si/Mg2Si multilayers in initial state and after thermal annealing were studied by methods of transmission electron microscopy and X-Ray scattering. As-deposited magnesium silicide layers are amorphous with nanocrystal inclusions of metastable h-Mg2Si. Formation of Mg2Si in hexagonal modification occurs under the influence of stress produced by silicon layers. At T = 723 К Mg2Si layers finished crystallizes in hexagonal modification, with some coarsening of grains. That is accompanied with 7.3 % reduction in period of the Si/Mg2Si multilayer.

  16. Influence of Mg Content on Deformability of AlMg Alloys during Extrusion

    Leśniak D.


    Full Text Available In this study the research on deformability of AlMg alloys with high Mg contents in extrusion was carried out. The different shapes from AlMg alloys containing 3.5%, 4.5% and 5.5% of Mg were extruded on 500 T semi-industrial press by using one-hole and multi-hole flat dies. The extrudates surface quality was under investigations in relation with the temperature-speed parameters of the extrusion process. The metal exit speed was estimated depending on the extrudates shape, wall thickness and Mg content. The alloy’s border solidus and liquidus temperatures were also determined.

  17. Viscosities of FenO-MgO-SiO2 and FenO-MgO-CaO-SiO2 slags

    戴曦; 甘雪萍; 张传福


    The viscosities of molten Fen O-MgO-SiO2 and Fen O-MgO-CaO-SiO2 semi-synthetic slags for nickel flash smelting were mearured in the temperature range of 1 200-1 450℃ by use of a rotational viscometer.The mass ratio of Fe to SiO2 was fixed at 1.2,calcium oxide and magnesium oxide contents varied in the range of 2%-8% and 9%-12%(mass fraction),respectively.The results show that silicate anions become smaller by increasing CaO content,which results in the viscosity decrease of slag.In the case of addition of MgO the viscosity behaviour is complicated When MgO content is less than 11%,the viscosity increases with the increase of MgO at all temperatures tested .However,when the MgO content is more than 11%,the viscosity decreases slightly for Fen O-MgO-CaOSiO2 system.At higher MgO contents,low-viscosity slags can be obtained by adding CaO.As for a given composition,the viscosity decreased with increasing temperature.The higher the temperature,the more MgO can be added before saturation.The effect of Fe3 O4 on the viscosity is quite significant.The viscosity of slag increases to 300 mpa tions of temperature and composition.A comparison between Fen O-MgO-SiO2 and Fen O-MgO-CaO-SiO2 systems are also given.

  18. Enhanced cycling stability and high rate dischargeability of (La,Mg)2Ni7-type hydrogen storage alloys with (La,Mg)5Ni19 minor phase

    Liu, Jingjing; Han, Shumin; Han, Da; Li, Yuan; Yang, Shuqin; Zhang, Lu; Zhao, Yumeng


    The A2B7-type lanthanum (La)-magnesium (Mg)-nickel (Ni)-based alloy with single (La,Mg)2Ni7 phase and different amounts of (La,Mg)5Ni19 minor phase was obtained by step-wise sintering. The impact of (La,Mg)5Ni19 phase on the alloy's microstructure and electrochemical performance was subsequently studied. It was found that the average subunit volume in (La,Mg)5Ni19 phase is smaller than that in (La,Mg)2Ni7 phase, resulting in increases of strains inside the alloys and decreases of cell volumes. During battery charge/discharge, the (La,Mg)5Ni19 phase network scattered in the alloys relieves internal stress, alleviates pulverization and oxidation of the alloys, stabilizes the stacking structures against amorphization, and finally improves the cycling stability of the alloys. Furthermore, (La,Mg)5Ni19 phase with higher Ni content desorbs hydrogen ahead of (La,Mg)2Ni7 phase. The reduced hydrogen pressure in (La,Mg)5Ni19 phase can subsequently lead to the fast discharge of (La,Mg)2Ni7 phase, thus making a remarkable improvement in high rate dischargeability at 1500 mA g-1 from 46.2% to 58.9% with increasing (La,Mg)5Ni19 phase abundance from 0 to 37.4 wt.%. Therefore, it is believed that A2B7-type La-Mg-Ni-based alloys with A5B19-type minor phase are promising prototypes for high-power and long-lifetime nickel/metal hydride battery electrode materials.

  19. Increased rate of Cori cycle in obese subjects with NIDDM and effect of weight reduction.

    Zawadzki, J K; Wolfe, R R; Mott, D M; Lillioja, S; Howard, B V; Bogardus, C


    To determine the contribution of the rate of glucose recycling via the Cori cycle (glucose----3-carbon compounds----glucose) to the higher rate of endogenous glucose production (EGPR) in subjects with non-insulin-dependent diabetes mellitus (NIDDM), we studied eight obese, weight-stabilized diabetic Pima Indians before [93.1 +/- 5.4 kg, 38 +/- 2% body fat, fasting plasma glucose (FPG) 254 +/- 11 mg/dl] and after (87.7 +/- 4.7 kg, 36 +/- 2% body fat, FPG 153 +/- 17 mg/dl) a 5-wk weight-loss diet and eight obese Indians (95.0 +/- 4.2 kg, 36 +/- 2% body fat, FPG 97 +/- 1 mg/dl) with normal glucose tolerance. EGPR and glucose recycling rate were measured during a 4-h primed continuous tracer infusion of [1-13C]glucose, and the rate of reincorporation of 1-13C of glucose into C2-6 positions in glucose was quantified by gas chromatography mass spectrometry. Substrate utilization rates were measured by simultaneous indirect calorimetry. EGPR (corrected for measured rate of recycling) decreased in the diabetic subjects from 3.80 to 2.74 fat-free mass (FFM) (P less than .01) after weight loss, approaching the rate observed in nondiabetic subjects (2.09 FFM).(ABSTRACT TRUNCATED AT 250 WORDS)

  20. Ultrafast Synthesis and Related Phase Evolution of Mg2Si and Mg2Sn Compounds

    Zhang, Qiang; Lu, Qiangbing; Yan, Yonggao; Su, Xianli; Tang, Xinfeng


    Both Mg2Si and Mg2Sn compounds were synthesized by an ultra-fast self-propagating high-temperature synthesis (SHS) method. The data regarding SHS were obtained via theoretical calculation combined with experiments, showing that the adiabatic temperature T ad and ignition temperature T ig of Mg2Si are a little higher than those of Mg2Sn. The mechanism of phase evolution and the concomitant microstructure evolution during the synthesis process of Mg2Si and Mg2Sn compounds were investigated by adopting SHS technique coupled with a sudden quenching treatment. Differential scanning calorimetry (DSC), field emission scanning electron microscopy (FESEM), and x-ray powder diffraction (XRD) results indicate that Mg2Si compound can be directly synthesized through the reaction of Mg and Si elements at around 850 K. Correspondingly, the formation of Mg2Sn needs to undergo melting of Sn and the subsequent feeble reaction between Mg and Sn elements before the large scale transformation at 730 K. As the groundwork, this research embodies great significance for future study on the ultrafast SHS process of the ternary Mg2Si1-x Sn x solid solutions.

  1. Formation and Corrosion Resistance of Mg-Al Hydrotalcite Film on Mg-Gd-Zn Alloy

    Ba, Z. X.; Dong, Q. S.; Kong, S. X.; Zhang, X. B.; Xue, Y. J.; Chen, Y. J.


    An environment-friendly technique for depositing a Mg-Al hydrotalcite (HT) (Mg6Al2(OH)16-CO3ṡ4H2O) conversion film was developed to protect the Mg-Gd-Zn alloy from corrosion. The morphology and chemical compositions of the film were analyzed by scanning electronic microscope (SEM) equipped with energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD) and Raman spectroscopy (RS), respectively. The electrochemical test and hydrogen evolution test were employed to evaluate the biocorrosion behavior of Mg-Gd-Zn alloy coated with the Mg-Al HT film in the simulated body fluid (SBF). It was found that the formation of Mg-Al HT film was a transition from amorphous precursor to a crystalline HT structure. The HT film can effectively improve the corrosion resistance of magnesium alloy. It indicates that the process provides a promising approach to modify Mg-Gd-Zn alloy.

  2. In vitro biocompatibility of Ti–Mg alloys fabricated by direct current magnetron sputtering

    Hieda, Junko, E-mail:; Niinomi, Mitsuo; Nakai, Masaaki; Cho, Ken


    . Consequently, it is revealed that the Ti–33Mg alloy film evaluated in this study is suitable for biomedical applications. - Highlights: • Biocompatibility of Ti–Mg alloys fabricated by magnetron sputtering was investigated. • The dissolution amounts of Ti are below or near the detection limit of ICP-OES. • The dissolution amounts of Mg increase rapidly in the Ti–55Mg alloy and Mg films. • Calcium phosphate is precipitated on the surfaces of the Ti–33Mg and Ti–55Mg alloys. • Ti–33Mg alloy film exhibits high corrosion resistance and good biocompatibility.

  3. Study of Microbiologically Induced Corrosion Action on Al-6Mg-Zr and Al-6Mg-Zr-Sc


    The corrosion behaviors of Al-6Mg-Zr and Al-6Mg-Zr-Sc in the sulfate-reducing bacteria (SRB) solution in anaerobic environment were studied using electrochemical, microbiological, and surface analysis methods. It was found that the oxide film was more compact owing to the addition of Sc resulting in the open circuit potential shifting by about 100mV positively. On the other hand, it was seen that the pitting sensitivity of Al-6Mg-Zr-Sc alloy in SRB solution decreased and its microbiologically influenced corrosion resistance was improved. Pitting corrosion occurring on the surface of the two alloys under the comprehensive action of the metabolism of SRB was observed by SEM. It was obtained by EDS that the corrosion degree increased with time and corrosion was furthered by deposition of the product.

  4. Isoprenaline increases serum levels of monocyte chemoattractant protein-1 and tissue inhibitor of matrix metalloproteinases type Ⅰ in Wistar rats

    LEI He-ping; ZHANG Meng-zhen; YANG Xiang-yu; HOU Xing-hua; LIN Qiu-xiong; YANG Min; ZHONG Shi-long


    Background Treatment of rats with the beta-adrenergic agonist Isoprenaline (ISO) results in cardiac hypertrophy and myocardial fibrosis.In the present work,we aimed to study the in vivo effects of ISO on serum levels of monocyte chemoattractant protein-1 and tissue inhibitor of matrix metalloproteinases type Ⅰ in Wistar rats.Methods ISO (5 mg· kg-1) or Saline were injected subcutaneously into Wistar rats once a day for 3 or 7 consecutive days.Ventricular remodeling and cardiac function were evaluated by echocardiography.Sections of heart were stained with hematoxylin-eosin (HE) for histopathology or with Masson's trichrome for collagen visualization.In addition,heart tissue immunohistochemistry for α-SMA was also analyzed.The serum levels of tissue inhibitor of matrix metalloproteinases type Ⅰ (TIMP-1) and monocyte chemoattractant protein-1 (MCP-1) were determined by Luminex multiplex technology.Results ISO induced cardiac dysfunction in rats after 3 or 7 days of treatment.ISO caused significant increase of myocardial disorder and fibrosis withincreased α-SMA expression.ISO treated aats showed a significant increase in the serum levels of TIMP-1 and MCP-1.Conclusions Our study suggests that ISO induces profound cardiac remodeling accompanied with increase of serum TIMP-1 and MCP-1.

  5. Standardised extract of safed musli (Chlorophytum borivilianum) increases aphrodisiac potential besides being safe in male Wistar rats.

    Das, S; Singhal, S; Kumar, N; Rao, C M; Sumalatha, S; Dave, J; Dave, R; Nandakumar, K


    The standardised extract of root of safed musli (Chlorophytum borivilianum) was evaluated for its aphrodisiac potential and safety profile on reproductive system. Wistar albino rats were trained to provide sexual experience under a dim red light (10 W) in a glass tank. Male and female rats were placed periodically in the glass tank in a particular order, that is male followed by introduction of the receptive female. Dosing of extract was carried out for 54 days at 125 and 250 mg kg(-1) p.o to male rats. On 14th and 28th days, the animals were observed from the cage side for sexual behaviours. Safed musli at both dose levels enhanced sexual vigour and libido which might be useful for treatment of sexual dysfunction in male till 28th day. Safety profile was assessed after 54 days of drug treatment, where both doses showed an increase in sperm count and increase in sperm motility. Thus, it can be stated that both doses possessed the spermatogenic potential, which would be highly beneficial in treating oligospermia or low sperm count. After 54 days of study, there was increase in sperm abnormality (%) at both doses, but not more than 10%, which indicated that this formulation will not induce infertility.

  6. Parenteral nutrition-associated hyperglycemia in non-critically ill inpatients increases the risk of in-hospital mortality (multicenter study).

    Olveira, Gabriel; Tapia, María José; Ocón, Julia; Cabrejas-Gómez, Carmen; Ballesteros-Pomar, María D; Vidal-Casariego, Alfonso; Arraiza-Irigoyen, Carmen; Olivares, Josefina; Conde-García, Maria Del Carmen; García-Manzanares, Alvaro; Botella-Romero, Francisco; Quílez-Toboso, Rosa P; Cabrerizo, Lucio; Matia, Pilar; Chicharro, Luisa; Burgos, Rosa; Pujante, Pedro; Ferrer, Mercedes; Zugasti, Ana; Prieto, Javier; Diéguez, Marta; Carrera, María José; Vila-Bundo, Anna; Urgelés, Juan Ramón; Aragón-Valera, Carmen; Rovira, Adela; Bretón, Irene; García-Peris, Pilar; Muñoz-Garach, Araceli; Márquez, Efren; Del Olmo, Dolores; Pereira, José Luis; Tous, María C


    Hyperglycemia may increase mortality in patients who receive total parenteral nutrition (TPN). However, this has not been well studied in noncritically ill patients (i.e., patients in the nonintensive care unit setting). The aim of this study was to determine whether mean blood glucose level during TPN infusion is associated with increased mortality in noncritically ill hospitalized patients. This prospective multicenter study involved 19 Spanish hospitals. Noncritically ill patients who were prescribed TPN were included prospectively, and data were collected on demographic, clinical, and laboratory variables as well as on in-hospital mortality. The study included 605 patients (mean age 63.2 ± 15.7 years). The daily mean TPN values were 1.630 ± 323 kcal, 3.2 ± 0.7 g carbohydrates/kg, 1.26 ± 0.3 g amino acids/kg, and 0.9 ± 0.2 g lipids/kg. Multiple logistic regression analysis showed that the patients who had mean blood glucose levels >180 mg/dL during the TPN infusion had a risk of mortality that was 5.6 times greater than those with mean blood glucose levels 180 mg/dL) in noncritically ill patients who receive TPN is associated with a higher risk of in-hospital mortality.

  7. Parenteral Nutrition–Associated Hyperglycemia in Non–Critically Ill Inpatients Increases the Risk of In-Hospital Mortality (Multicenter Study)

    Olveira, Gabriel; Tapia, María José; Ocón, Julia; Cabrejas-Gómez, Carmen; Ballesteros-Pomar, María D.; Vidal-Casariego, Alfonso; Arraiza-Irigoyen, Carmen; Olivares, Josefina; Conde-García, Maria del Carmen; García-Manzanares, Álvaro; Botella-Romero, Francisco; Quílez-Toboso, Rosa P.; Cabrerizo, Lucio; Matia, Pilar; Chicharro, Luisa; Burgos, Rosa; Pujante, Pedro; Ferrer, Mercedes; Zugasti, Ana; Prieto, Javier; Diéguez, Marta; Carrera, María José; Vila-Bundo, Anna; Urgelés, Juan Ramón; Aragón-Valera, Carmen; Rovira, Adela; Bretón, Irene; García-Peris, Pilar; Muñoz-Garach, Araceli; Márquez, Efren; del Olmo, Dolores; Pereira, José Luis; Tous, María C.


    OBJECTIVE Hyperglycemia may increase mortality in patients who receive total parenteral nutrition (TPN). However, this has not been well studied in noncritically ill patients (i.e., patients in the nonintensive care unit setting). The aim of this study was to determine whether mean blood glucose level during TPN infusion is associated with increased mortality in noncritically ill hospitalized patients. RESEARCH DESIGN AND METHODS This prospective multicenter study involved 19 Spanish hospitals. Noncritically ill patients who were prescribed TPN were included prospectively, and data were collected on demographic, clinical, and laboratory variables as well as on in-hospital mortality. RESULTS The study included 605 patients (mean age 63.2 ± 15.7 years). The daily mean TPN values were 1.630 ± 323 kcal, 3.2 ± 0.7 g carbohydrates/kg, 1.26 ± 0.3 g amino acids/kg, and 0.9 ± 0.2 g lipids/kg. Multiple logistic regression analysis showed that the patients who had mean blood glucose levels >180 mg/dL during the TPN infusion had a risk of mortality that was 5.6 times greater than those with mean blood glucose levels 180 mg/dL) in noncritically ill patients who receive TPN is associated with a higher risk of in-hospital mortality. PMID:23223407

  8. Biochar increases arsenic release from an anaerobic paddy soil due to enhanced microbial reduction of iron and arsenic.

    Wang, Ning; Xue, Xi-Mei; Juhasz, Albert L; Chang, Zhi-Zhou; Li, Hong-Bo


    Previous studies have shown that biochar enhances microbial reduction of iron (Fe) oxyhydroxide under anaerobic incubation. However, there is a lack of data on its influence on arsenic (As) release from As-contaminated paddy soils. In this study, paddy soil slurries (120 mg As kg(-1)) were incubated under anaerobic conditions for 60 days with and without the addition of biochar (3%, w/w) prepared from rice straw at 500 °C. Arsenic release, Fe reduction, and As fractionation were determined at 1, 10, 20, 30, and 60 d, while Illumina sequencing and real-time PCR were used to characterize changes in soil microbial community structure and As transformation function genes. During the first month of incubation, As released into soil solution increased sharply from 27.9 and 55.9 to 486 and 630 μg kg(-1) in unamended and biochar amended slurries, with inorganic trivalent As (As(III)) being the dominant specie (52.7-91.0% of total As). Compared to unamended slurries, biochar addition increased As and ferrous ion (Fe(2+)) concentrations in soil solution but decreased soil As concentration in the amorphous Fe/Al oxide fraction (F3). Difference in released As between biochar and unamended treatments (ΔAs) increased with incubation time, showing strong linear relationships (R(2) = 0.23-0.33) with ΔFe(2+) and ΔF3, confirming increased As release due to enhanced Fe reduction. Biochar addition increased the abundance of Fe reducing bacteria such as Clostridum (27.3% vs. 22.7%), Bacillus (3.34% vs. 2.39%), and Caloramator (4.46% vs. 3.88%). In addition, copy numbers in biochar amended slurries of respiratory As reducing (arrA) and detoxifying reducing genes (arsC) increased 19.0 and 1.70 fold, suggesting microbial reduction of pentavalent As (As(V)) adsorbed on Fe oxides to As(III), further contributing to increased As release.

  9. Elenoside increases intestinal motility

    E Navarro; SJ Alonso; R Navarro; J Trujillo; E Jorge


    AIM: To study the effects of elenoside, an arylnaphthalene lignan from Justicia hyssopifolia, on gastrointestinal motility in vivo and in vitro in rats.METHODS: Routine in vivo experimental assessments were catharsis index, water percentage of boluses,intestinal transit, and codeine antagonism. The groups included were vehicle control (propylene glycol-ethanolplant oil-tween 80), elenoside (i.p. 25 and 50 mg/kg),cisapride (i.p. 10 mg/kg), and codeine phosphate (intragastric route, 50 mg/kg). In vitro approaches used isolated rat intestinal tissues (duodenum, jejunum, and ileum). The effects of elenoside at concentrations of 3.2× 10-4, 6.4 × 10-4 and 1.2 × 10-3 mol/L, and cisapride at 10-6 mol/L were investigated.RESULTS: Elenoside in vivo produced an increase in the catharsis index and water percentage of boluses and in the percentage of distance traveled by a suspension of activated charcoal. Codeine phosphate antagonized the effect of 25 mg/kg of elenoside. In vitro, elenoside in duodenum, jejunum and ileum produced an initial decrease in the contraction force followed by an increase.Elenoside resulted in decreased intestinal frequency in duodenum, jejunum, and ileum. The in vitro and in vivo effects of elenoside were similar to those produced by cisapride.CONCLUSION: Elenoside is a lignan with an action similar to that of purgative and prokinetics drugs.Elenoside, could be an alternative to cisapride in treatment of gastrointestinal diseases as well as a preventive therapy for the undesirable gastrointestinal effects produced by opioids used for mild to moderate pain.

  10. Multilayer Mg: Stainless Steel Sheets, Microstructure, and Mechanical Properties

    Inoue, Junya; Sadeghi, Alireza; Kyokuta, Nobuhiko; Ohmori, Toshinori; Koseki, Toshihiko


    Different multilayer Mg AZ31 and SS304L steel sheet combinations were prepared with different volume fractions of Mg. Isolated stress-strain curves of the Mg layers showed significant improvements in the strength and elongation of multilayer samples. Results indicated that in the most extreme situation with the lowest Mg volume fraction (V f = 0.39), the ultimate strength was increased by 25 pct to 370 MPa and the elongation was improved by 70 pct to 0.34. Investigation of the fracture surface showed that failure occurs by the coalescence of cracks close to the interface region. The improved strength of the multilayer samples was due to the combined effect of surface crack prevention by the steel layer and the higher work-hardening rate caused by the possible increased activity of non-basal systems. It is suggested that the stronger work-hardening behavior and the enhanced activity of non-basal systems in the multilayer samples were due to the formation of new stress components in the transverse direction. The larger the volume fraction of steel in the multilayer, the longer the distance remaining unstrained before the UTS.

  11. Price increase


    Please take note that after five years of stable prices at Restaurant No 1 a price increase will come into force on 1st January 2006. This increase has been agreed after discussions between the CSR (Comité de Surveillance des Restaurants) and the catering company Novae and will reflect the inflation rate of the last few years. In addition, a new children's menu will be introduced, as well as 'Max Havelaar' fair-trade coffee at a price of 1.70 CHF.

  12. Price increase


    Please take note that after five years of stable prices at Restaurant No 1 a price increase will come into force on 1st January 2006. This increase has been agreed after discussions between the CSR (Comité de Surveillance des Restaurants) and the catering company Novae and will reflect the inflation rate of the last few years. In addition, a new children's menu will be introduced as well as 'Max Havelaar' fair-trade coffee at a price of 1.70 CHF.

  13. A comparison of amorphous calcium carbonate crystallization in aqueous solutions of MgCl2 and MgSO4: implications for paleo-ocean chemistry

    Han, Mei; Zhao, Yanyang; Zhao, Hui; Han, Zuozhen; Yan, Huaxiao; Sun, Bin; Meng, Ruirui; Zhuang, Dingxiang; Li, Dan; Liu, Binwei


    Based on the terminology of "aragonite seas" and "calcite seas", whether different Mg sources could affect the mineralogy of carbonate sediments at the same Mg/Ca ratio was explored, which was expected to provide a qualitative assessment of the chemistry of the paleo-ocean. In this work, amorphous calcium carbonate (ACC) was prepared by direct precipitation in anhydrous ethanol and used as a precursor to study crystallization processes in MgSO4 and MgCl2 solutions having different concentrations at 60 °C (reaction times 240 and 2880 min). Based on the morphology of the aragonite crystals, as well as mineral saturation indices and kinetic analysis of geochemical processes, it was found that these crystals formed with a spherulitic texture in 4 steps. First, ACC crystallized into columnar Mg calcite by nearly oriented attachment. Second, the Mg calcite changed from columnar shapes into smooth dumbbell forms. Third, the Mg calcite transformed into rough dumbbell or cauliflower-shaped aragonite forms by local dissolution and precipitation. Finally, the aragonite transformed further into spherulitic radial and irregular aggregate forms. The increase in Ca2+ in the MgSO4 solutions compared with the MgCl2 solutions indicates the fast dissolution and slow precipitation of ACC in the former solutions. The phase transition was more complete in the 0.005 M MgCl2 solution, whereas Mg calcite crystallized from the 0.005 M MgSO4 solution, indicating that Mg calcite could be formed more easily in an MgSO4 solution. Based on these findings, aragonite and Mg calcite relative to ACC could be used to provide a qualitative assessment of the chemistry of the paleo-ocean. Therefore, calcite seas relative to high-Mg calcite could reflect a low concentration MgSO4 paleo-ocean, while aragonite seas could be related to an MgCl2 or high concentration of MgSO4 paleo-ocean.

  14. Plasma electrolytic oxidation coating of synthetic Al-Mg binary alloys

    Tarakci, Mehmet, E-mail:


    The binary Al-Mg synthetic alloys were prepared in a vacuum/atmosphere controlled furnace with the addition of 0.5, 1, 2, 4, 7, and 15 wt.% pure Mg into pure aluminum as substrate material. The surfaces of the Al-Mg alloys and pure aluminum were coated for 120 min by plasma electrolytic oxidation in the same electrolyte of 12 g/L sodium silicate and 2 g/L KOH in distilled water. The coating was characterized by X-ray diffraction, scanning electron microscopy, profilometry and Vickers microhardness measurements. There regions of loose outer layer, dense inner layer with precipitate like particles of {alpha}-Al{sub 2}O{sub 3} and a thin transition layer were identified for the coated samples. The coating thickness increases from 85 to 150 {mu}m with Mg contents in the alloys. The surface morphology becomes more porous and consequently surface roughness tends to increase with plasma electrolytic oxidation treatment and further with Mg content. The increase in magnesium content reduces the formation of {alpha}-Al{sub 2}O{sub 3} and crystalline mullite phases in the coating and decreases microhardness of coating. The Mg concentration is constant throughout the other loose and dense regions of coating though it gradually decreases in the thin inner region. - Research Highlights: Black-Right-Pointing-Pointer The average thickness of PEO coating of Al-Mg alloys increases with Mg content. Black-Right-Pointing-Pointer The addition of Mg reduces and prevents the formation of {alpha}-Al{sub 2}O{sub 3} and mullite. Black-Right-Pointing-Pointer The surface roughness increases with Mg content in the Al-Mg alloys. Black-Right-Pointing-Pointer The hardness values of the coating decreases with the Mg amount in the substrate. Black-Right-Pointing-Pointer The Mg concentration is constant throughout the main regions of coating.

  15. Bias voltage effects on tunneling magnetoresistance in Fe/MgAl2O4/Fe (001 ) junctions: Comparative study with Fe/MgO/Fe(001) junctions

    Masuda, Keisuke; Miura, Yoshio


    We investigate bias voltage effects on the spin-dependent transport properties of Fe/MgAl 2O 4 /Fe(001) magnetic tunneling junctions (MTJs) by comparing them with those of Fe/MgO/Fe(001) MTJs. By means of the nonequilibrium Green's function method and the density functional theory, we calculate bias voltage dependencies of magnetoresistance (MR) ratios in both the MTJs. We find that in both the MTJs, the MR ratio decreases as the bias voltage increases and finally vanishes at a critical bias voltage Vc. We also find that the critical bias voltage Vc of the MgAl 2O 4 -based MTJ is clearly larger than that of the MgO-based MTJ. Since the in-plane lattice constant of the Fe/MgAl 2O 4 /Fe(001) supercell is twice that of the Fe/MgO/Fe(001) one, the Fe electrodes in the MgAl 2O 4 -based MTJs have an identical band structure to that obtained by folding the Fe band structure of the MgO-based MTJs in the Brillouin zone of the in-plane wave vector. We show that such a difference in the Fe band structure is the origin of the difference in the critical bias voltage Vc between the MgAl 2O 4 - and MgO-based MTJs.

  16. Hydrodechlorination of Tetrachloromethane over Palladium Catalysts Supported on Mixed MgF₂-MgO Carriers.

    Bonarowska, Magdalena; Wojciechowska, Maria; Zieliński, Maciej; Kiderys, Angelika; Zieliński, Michał; Winiarek, Piotr; Karpiński, Zbigniew


    Pd/MgO, Pd/MgF₂ and Pd/MgO-MgF₂ catalysts were investigated in the reaction of CCl₄ hydrodechlorination. All the catalysts deactivated in time on stream, but the degree of deactivation varied from catalyst to catalyst. The MgF₂-supported palladium with relatively large metal particles appeared the best catalyst, characterized by good activity and selectivity to C₂-C₅ hydrocarbons. Investigation of post-reaction catalyst samples allowed to find several details associated with the working state of hydrodechlorination catalysts. The role of support acidity was quite complex. On the one hand, a definite, although not very high Lewis acidity of MgF₂ is beneficial for shaping high activity of palladium catalysts. The MgO-MgF₂ support characterized by stronger Lewis acidity than MgF₂ contributes to very good catalytic activity for a relatively long reaction period (~5 h) but subsequent neutralization of stronger acid centers (by coking) eliminates them from the catalyst. On the other hand, the role of acidity evolution, which takes place when basic supports (like MgO) are chlorided during HdCl reactions, is difficult to assess because different events associated with distribution of chlorided support species, leading to partial or even full blocking of the surface of palladium, which plays the role of active component in HdCl reactions.

  17. Effects of warming on uptake and translocation of cadmium (Cd) and copper (Cu) in a contaminated soil-rice system under Free Air Temperature Increase (FATI).

    Ge, Li-Qiang; Cang, Long; Liu, Hui; Zhou, Dong-Mei


    Global warming has received growing attentions about its potential threats to human in recent, however little is known about its effects on transfer of heavy metals in agro-ecosystem, especially for Cd in rice. Pot experiments were conducted to evaluate Cd/Cu translocation in a contaminated soil-rice system under Free Air Temperature Increase (FATI). The results showed that warming gradually decreased soil porewater pH and increased water-soluble Cd/Cu concentration, reduced formation of iron plaque on root surface, and thus significantly increased total uptake of Cd/Cu by rice. Subsequently, warming significantly promoted Cd translocation from root to shoot, and increased Cd distribution percentage in shoot, while Cu was not significantly affected. Enhanced Cd uptake and translocation synergistically resulted in higher rice grain contamination with increasing concentration from 0.27 to 0.65 and 0.14-0.40 mg kg(-1) for Indica and Japonica rice, respectively. However increase of Cu in brown grain was only attributed to its uptake enhancement under warming. Our study provides a new understanding about the food production insecurity of heavy metal contaminated soil under the future global warming.

  18. Hydrothermal replacement of calcite by Mg-carbonates

    Jonas, Laura; Mueller, Thomas; Dohmen, Ralf


    phases increases with increasing distance from the unreacted calcite core, countered by a decrease of Ca incorporated. Both the coexistence of two different product phases and the distinct compositional gradient within the forming reaction rim are unequivocal signs of a chemical zonation of Ca and Mg in the fluid phase which mediates the element exchange between the reaction interface and the bulk solution. Atomic adsorption spectroscopy revealed that the Ca/Mg ratio in the reacted fluid increases as a function of time, reflecting the progressive exchange of Mg and Ca between the fluid and the solid phase. The time-dependence of the evolving Ca/Mg ratio can be fitted with a square root of time relation that indicates a transport controlled reaction. We interpret the hydrothermal replacement of calcite to operate via a dissolution/re-precipitation mechanism, whereas the reaction progress is controlled by the transport of the structure forming elements through the developing reaction rim.

  19. Resveratrol Induces Apoptosis in Human Osteosarcoma MG63 Cells

    Yan Liu; Xin Wang; Yuxin Xie; Jingui Zhang; Qingshan Wang; Xianhui Xu


    OBJECTIVE To investigate apoptosis in human osteosarcoma MG63 cells induced by resveratrol and the molecular mechanism involved.METHODS MG63 cells were treated with different concentrations of resveratrol and transmission electron microscopy was used to observe morphological changes occurring in apoptosis.The MTT method was used to determine the inhibitory rate and flow cytometry was used to assess apoptosis and to analyze the expression of the p21ciP1/WAF1 and survivin proteins;the expression of p21ciP1/WAF1 and survivin mRNAs was analyzed by the reverse transcriptase polymerase chain reaction (RT-PCR).RESULTS After resveratrol treatment,the growth of the MG63 cells was significantly inhibited in a time- and dose-dependent fashion.By transmission electron microscopy,the cells displayed morphological changes characteristic of apoptosis,including formation of cytoplasmic vacuoles,chromatin condensation and margination.Flow cytometry showed that the growth of the cells was inhibited after resveratrol (10 mg/L and 20 mg/L) treatment.The inhibitory rates were (11.9 ±0.63)% and (19.7 ± 0.88)%respectively.The quantity of treated cells in G0/G1 transition was increased,but the number in the S phase and G2/M transition was decreased.A subdiploid peak was observed.The expression of p21ciP1/WAF1 was up-regulated while survivin was down-regulated.CONCLUSION Resveratrol can inhibit growth and induce apoptosis of MG63 cells.Its molecular mechanism might be related to modulation of survivin and p21ciP1/WAF1 expression.

  20. Low-temperature synthesis of MgB2 via powder metallurgy processing

    Birol, Yucel


    Ball-milled Mg/B2O3 powder blends reveal interpenetrating layers of deformed magnesium and boron oxide grains that are increasingly refined with increasing milling time. Boron oxide is reduced by Mg and MgO thus formed reacts with the remaining B2O3 to produce Mg3(BO3)2 during ball milling for 30 min. Both B2O3 and Mg3(BO3)2 react with Mg to produce MgB2 upon further ball milling. An annealing treatment can be employed when ball milling is performed for less than 1 h as thermal exposure of the ball-milled Mg/B2O3 powder blends also leads to the formation of MgB2. The above reactions take place between 500 and 700 °C when the Mg/B2O3 powder blend is ball milled for 30 min, and between 450 and 550 °C, after ball milling for 1 h. This is a very attractive route owing to processing temperatures where the volatility of Mg is no longer a problem.

  1. Influence of Light Calcining Hydration of Magnesite on MgO Sintering

    LI Huan; YU Jingkun; KUANG Shibo


    Sintered magnesia clinker (also called sintered MgO ) was prepared with Mg(OH)2 (prepared by light calcining hydration of magnesite) and magnesite as starting materials, respectively, by the technical process : light calcining (850 ℃ 1 h )→grinding → molding →firing ( 1 600 ℃ 3 h ). The morphology and struc-ture of light calcined MgO powders prepared with mag-nesite or Mg(OH)2 were analyzed by XRD, SEM and FT-IR. The sinterability and microstructure of sintered magnesia prepared with magnesite or Mg(OH)2 were re-searched. The results showed that: (1) light calcined MgO powders prepared with magnesite or Mg (OH)2 were both face-centered cubic structure. The light cal-cined MgO prepared with magnesitehad the residual of functional group CO32- , and that prepared with Mg (OH)2 didn't have CO32-, and was easy to break, which reduced the grinding time. (2) Because of the high activity of the light calcined MgO prepared with Mg(OH)2 and the catalysis of the water residual in the decomposing process of Mg(OH)2, the apparent porosity of sintered magnesia decreased to 0.6% from 2.0% of before hydration, closed porosity decreased to 2.8% from 6.1%, and bulk density increased to 3.46 g·cm-3 from 3.29 g·cm-3

  2. Gastroduodenal tolerance of 75 mg clopidogrel versus 325 mg aspirin in healthy volunteers. A gastroscopic study.

    Fork, F T; Lafolie, P; Tóth, E; Lindgärde, F


    Clopidogrel is a new antiplatelet agent that offers increased protection over aspirin in preventing vascular ischaemic events in patients with symptomatic atherosclerosis. In a large, randomized, international study of clopidogrel and aspirin (n = 19,185 patients) clopidogrel was associated with a lower incidence of gastrointestinal adverse events, including gastrointestinal haemorrhage and hospitalizations because of gastrointestinal haemorrhage. The aim of the study was to determine whether macroscopic differences in the gastric mucosa between aspirin- and clopidogrel-treated subjects could be detected by gastroscopy after short-term treatment. Thirty-six healthy volunteers were randomized in a double-blind, double-dummy, parallel design, to 75 mg/day of clopidogrel or 325 mg/day of aspirin for 8 days. Gastroscopy was performed at base line before administration of study drug and directly after treatment completion. Gastroduodenal effects were measured in accordance with a modified Lanza scale. At base line no difference between the groups was detected (median Lanza score, 0.0 in both groups). At the end of treatment the aspirin group showed a median score of 7.5, and the clopidogrel group showed an unchanged median score of 0.0 (P < 0.001). In the aspirin group 13 individuals reported 19 adverse events versus 8 individuals and 13 adverse events for clopidogrel, with approximately half of the adverse events being gastrointestinal in each group. No serious adverse events were reported. In contrast to aspirin, short-term treatment with clopidogrel does not induce macroscopic changes in the gastroduodenal mucosa. The study results show that in patients without gastroduodenal disease clopidogrel, but not aspirin, does not induce any gastroscopically evident erosions during short-term treatment.

  3. Preparation of Metallic Isotope 26Mg

    WuXiaolei; ZhangFuming; GanZaiguo; GuoJunsheng; QinZhi


    Some special isotope material is usually used in nuclear experiments. It can be served as ion beam or target. When new superheavy nuclide 265Bh (Z=107) is synthesized, a reaction of 243Am target with 26Mg ion beamis selected to produce new isotope 265Bh. The preparation and production of this rare and extremely expensive isotope 26 Mg used for ion beam substance will be a key problem in synthesizing experiment of 265Bh. Theavailable chemical form of isotope 26Mg in commercial product usually is oxide or other compound, which are not required in our experiment. They need to be transformed to metal form as a proper working substance in ion source.

  4. Hydrogenation properties of Mg-Al alloys

    Andreasen, Anders


    In this paper the properties of Mg-Al alloys in relation to hydrogen storage are reviewed. The main topics of this paper are materials preparation, hydrogen capacity, thermodynamics of hydride formation, and the kinetics of hydride formation and decomposition. Hydrogenation of Mg-Al leads...... to disproportionation with the formation of magnesium hydride and metallic aluminum as the final product. Experimental evidence renders this process reversible. It is observed that the enthalpy of hydride formation of magnesium is lowered upon alloying with Al due to a slightly endothermic disproportionation reaction....... Further, it is found that the kinetics of hydrogenation, as well dehydrogenation, may be significantly improved by alloying compared to pure Mg. The expense of these improvements of the hydrogenation/dehydrogenation properties is a lower gravimetric hydrogen density in the hydrogenated product, (C) 2008...

  5. High Spin States in ^24Mg

    Schwartz, J.; Lister, C. J.; Wuosmaa, A.; Betts, R. R.; Blumenthal, D.; Carpenter, M. P.; Davids, C. N.; Fischer, S. M.; Hackman, G.; Janssens, R. V. F.


    The ^12C(^16O,α)^24Mg reaction was used at 51.5MeV to populate high angular momentum states in ^24Mg. Gamma-rays de-exciting high spin states were detected in a 20 detector spectrometer (the AYE-ball) triggered by the ANL Fragment Mass Analyser (FMA). Channel selection, through detection of ^24Mg nuclei with the appropriate time of flight, was excellent. All the known decays from high spin states were seen in a few hours, with the exception of the 5.04 MeV γ-decay of the J^π=9^- state at 16.904 MeV footnote A.E.Smith et al., Phys. Lett. \\underlineB176, (1986)292. which could not be confirmed. The potential of the technique for studying the radiative decay of states with very high spin in light nuclei will be discussed.

  6. Phase equilibrium in Mg-Cu-Y

    Mezbahul-Islam, Mohammad; Medraj, Mamoun


    Magnesium-based bulk metallic glasses (BMG) have potential in applications ranging from biomedical to sports equipment and the Mg-Cu-Y system offers some of the most promising alloys. Phase relations and ternary solubility of the binary and ternary compounds of this system have been experimentally investigated. The Isothermal section of Mg-Cu-Y system at 673 K for the entire composition range has been constructed. Phase relations in the Cu-rich (>66 at.% Cu) region of the Mg-Cu-Y system has been determined for the first time. The homogeneity range of three ternary compounds has been determined. Solidifications behavior of several key alloys have been discussed based on the differential scanning calorimetry (DSC) experiments and thermodynamic calculations. Extensive analysis of the DSC curves has been carried out to relate them to the corresponding phase transformation reactions and temperatures. Some of the most promising metallic glass forming regions have been analyzed using thermodynamic calculations.

  7. Increasing Selenium and Yellow Pigment Concentrations in Foxtail Millet (Setaria italica L.) Grain with Foliar Application of Selenite.

    Ning, Na; Yuan, Xiang-Yang; Dong, Shu-Qi; Wen, Yin-Yuan; Gao, Zhen-Pan; Guo, Mei-Jun; Guo, Ping-Yi


    Although addition of selenium (Se) is known to increase Se in crops, it is unclear whether exogenous Se is linked to nutritional and functional components in foxtail millet (Setaria italica L.). In this study, we examined the potential of increasing Se and yellow pigment (YP) in foxtail millet grain by foliar application of Se. Field experiments were conducted during the growing season of foxtail millet in 2013 and 2014 to assess the effects of foliar spray of sodium selenite (10-210 g Se ha(-1)) on the yield, Se uptake and accumulation, total YP, and microminerals in the grain. Average grain yields with Se application were 5.60 and 4.53 t ha(-1) in the 2 years, showing no significant differences from the unfertilized control. However, grain Se concentration increased linearly with Se application rate, by 8.92 and 6.09 μg kg(-1) in the 2 years with application of 1 g Se ha(-1) (maximum grain recovery rates of Se fertilizer, 52 and 28 %). Likewise, total grain YP concentration markedly increased by 0.038 and 0.031 mg kg(-1) in the 2 years with application of 1 g Se ha(-1). Grain Mn, Cu, Fe, and Zn concentrations were not significantly affected by Se application. This study indicated that foliar application of Se effectively and reliably increased the concentrations of Se and YP in foxtail millet grain without affecting the yield or mineral micronutrient concentrations. Thus, foliar-applied selenite has a significant potential to increase the concentrations of selenium and YP (putative lutein (Shen, J Cereal Sci 61:86-93, 2015; Abdel-Aal, Cereal Chem 79:455-457, 2002; Abdel-Aal, J Agric Food Chem 55:787-794, 2007)) of foxtail millet and, thus, the health benefits of this crop.

  8. Phase Equilibria of the Ce-Mg-Zn Ternary System at 300 °C

    Ahmad Mostafa


    Full Text Available The isothermal section of the Ce-Mg-Zn system at 300 °C was experimentally established in the full composition range via diffusion multiple/couples and key alloys. Annealed key alloys were used to confirm the phase equilibria obtained by diffusion multiple/couples and to determine the solid solubility ranges. Spot analysis was carried out, using wavelength dispersive X-ray spectroscopy (WDS, to identify the composition of the observed phases. The composition profiles were obtained using WDS line-scans across the diffusion zones. X-ray diffraction (XRD was performed to identify the phases in the annealed alloys and to confirm the WDS results. Eight ternary compounds, in the Ce-Mg-Zn isothermal section at 300 °C, were observed from 45–80 at.% Zn. These are: τ1 (Ce6Mg3Zn19, τ2 (CeMg29Zn25, τ3 (Ce2Mg3Zn3, τ4 (CeMg3Zn5, τ5 (CeMg7Zn12, τ6 (CeMg2.3−xZn12.8+x; 0 ≤ x ≤ 1.1, τ7 (CeMgZn4 and τ8 (Ce(Mg1−yZny11; 0.096 ≤ y ≤ 0.43. The ternary solubility of Zn in the Ce-Mg compounds was found to increase with a decrease in Mg concentration. Accordingly, the ternary solid solubility of Zn in CeMg12 and CeMg3 was measured as 5.6 and 28.4 at.% Zn, respectively. Furthermore, the CeMg and CeZn showed a complete solid solubility. The complete solubility was confirmed by a diffusion couple made from alloys containing CeMg and CeZn compounds.

  9. Mg3(VO4)2-MgO-ZrO2 nano-catalysts for oxidative dehydrogenation of n-butane.

    Lee, Jong Kwon; Seo, Hyun; Hong, Ung Gi; Yoo, Yeonshick; Cho, Young-Jin; Lee, Jinsuk; Park, Gle; Chang, Hosik; Song, In Kyu


    A series of X-Mg3(VO4)2-MgO-ZrO2 nano-catalysts with different vanadium content (X = 3.3, 5.3, 7.0, 10.2, and 13.4) were prepared by a single-step citric acid-derived sol-gel method for use in the oxidative dehydrogenation of n-butane to n-butene and 1,3-butadiene. The effect of vanadium content of X-Mg3(VO4)2-MgO-ZrO2 nano-catalysts on their physicochemical properties and catalytic activities in the oxidative dehydrogenation of n-butane was investigated. Successful formation of X-Mg3(VO4)2-MgO-ZrO2 nano-catalysts was confirmed by XRD, Raman spectroscopy, and ICP-AES analyses. The catalytic performance of X-Mg3(VO4)2-MgO-ZrO2 nano-catalysts strongly depended on vanadium content. All the X-Mg3(VO4)2-MgO-ZrO2 nano-catalysts showed a stable catalytic performance without catalyst deactivation during the reaction. Among the catalysts tested, 7.0-Mg3(VO4)2-MgO-ZrO2 nano-catalyst showed the best catalytic performance in terms of yield for total dehydrogenation products (TDP, n-butene and 1,3-butadiene). TPRO (temperature-programmed reoxidation) experiments were carried out to measure the oxygen capacity of the catalyst. Experimental results revealed that oxygen capacity of the catalyst was closely related to the catalytic performance. Yield for TDP increased with increasing oxygen capacity of the catalyst.

  10. Microstructure evolution and photoluminescence in nanocrystalline Mg(x)Zn(1 - x)O thin films.

    Sahaym, U; Norton, M G; Huso, J; Morrison, J L; Che, H; Bergman, L


    The effects of Mg concentration and annealing temperature on the characteristics of nanocrystalline Mg(x)Zn(1 - x)O thin films (where x = 0-0.4) were studied using electron microscopy and photoluminescence. The films were prepared by a sol-gel method. The solid solubility limit of MgO in ZnO for the sol-gel-derived Mg(x)Zn(1 - x)O films in the present study was determined to be ∼ 20 at.%. Microstructural characterization of the films showed that the wurtzite crystallites decrease in size with increase in Mg concentration up to the solubility limit. Increasing Mg concentration beyond the solubility limit resulted in a decrease in crystallinity of the films. The bandgap energy was found to increase with Mg concentration whereas the linewidth first increased and then decreased when the Mg concentration was increased beyond the solubility limit. Photoluminescence properties have been correlated to the microstructure of the films. A growth mechanism for Mg(x)Zn(1 - x)O nanocrystalline films under the present processing conditions has also been proposed.

  11. Superconductivity in MgB2


    In January of 2001 the superconductivity of the compound MgB2 with a critical temperature Tc of up to 39 K was discovered. This Tc is the highest in all intermetallic compound and alloy superconductors. MgB2 has a simple structure and its manufacturing capital cost is lower, therefore it could become a practical superconductor in the future. The recent progress is reviewed here which covers the progress in electronic structure, high Tc mechanism, superconducting parameters (Debye temperature, specific heat coefficient of electron, critical fields, coherent length, penetration depth, energy gap, critical current and relaxation rate of flux). Moreover the issue on power transmission is discussed.

  12. Electron microscopy observations of MgB 2 wire prepared by an internal Mg diffusion method

    Shimada, Y.; Kubota, Y.; Hata, S.; Ikeda, K.; Nakashima, H.; Matsumoto, A.; Togano, K.; Kumakura, H.


    Microstructure in a high-density MgB2 wire fabricated by an internal Mg diffusion (IMD) process has been investigated by electron microscopy imaging and analysis at different scales. In the IMD process, a pure Mg rod was used as Mg source, and nanosized SiC powders were mixed with amorphous B powders. In the case of a heat treatment at 640 °C for 1 h carried out after rolling and drawing processes, the wire has two microstructural features that degrade critical current density: uncrystallized zones composed mainly of unreacted B and SiC powders, and cracks partly filled with course Mg2Si crystals. Those cracks were formed in the uncrystallized zones as well as in crystallized MgB2 zones. It indicate that the cracks formed by the mechanical milling and drawing remain after the heat treatment.

  13. Vitamin K prophylaxis for premature infants: 1 mg versus 0.5 mg.

    Costakos, Dennis T; Greer, Frank R; Love, Laureen A; Dahlen, Lynn R; Suttie, John W


    We studied babies (22 to 32 weeks gestational age) of mothers wishing to breast-feed. Group 1 received 1 mg of vitamin K and Group 2 received 0.5 mg of vitamin K. The Day 2 plasma levels of vitamin K were 1900 to 2600 times higher on average, and the Day 10 vitamin K levels 550 to 600 times higher on average, relative to normal adult plasma values, whether an initial prophylaxis dose of 0.5 mg or 1 mg was used. We conclude that 0.5 mg as the initial dose of vitamin K intramuscularly or intravenously would likely be more than adequate to prevent hemorrhagic disease of the newborn, and that 0.3 mg/per kg may be used for babies with birth weights below 1000 g. To decrease vitamin K intakes in this population, new preparations of total parenteral nutrition multivitamins are needed.

  14. Efficient hydrogen storage with the combination of lightweight Mg/MgH2 and nanostructures.

    Cheng, Fangyi; Tao, Zhanliang; Liang, Jing; Chen, Jun


    Efficient hydrogen storage plays a key role in realizing the incoming hydrogen economy. However, it still remains a great challenge to develop hydrogen storage media with high capacity, favourable thermodynamics, fast kinetics, controllable reversibility, long cycle life, low cost and high safety. To achieve this goal, the combination of lightweight materials and nanostructures should offer great opportunities. In this article, we review recent advances in the field of chemical hydrogen storage that couples lightweight materials and nanostructures, focusing on Mg/MgH(2)-based systems. Selective theoretical and experimental studies on Mg/MgH(2) nanostructures are overviewed, with the emphasis on illustrating the influences of nanostructures on the hydrogenation/dehydrogenation mechanisms and hydrogen storage properties such as capacity, thermodynamics and kinetics. In particular, theoretical studies have shown that the thermodynamics of Mg/MgH(2) clusters below 2 nm change more prominently as particle size decreases.

  15. Mifepristone 5 mg versus 10 mg for emergency contraception: double-blind randomized clinical trial

    Carbonell JL


    Full Text Available Josep Lluis Carbonell,1 Ramon Garcia,2 Adriana Gonzalez,2 Andres Breto,2 Carlos Sanchez2 1Mediterranea Medica Clinic, Valencia, Spain; 2Eusebio Hernandez Gynecology and Obstetrics Teaching Hospital, Havana, Cuba Purpose: To estimate the efficacy and safety of 5 mg and 10 mg mifepristone for emergency contraception up to 144 hours after unprotected coitus. Methods: This double-blind randomized clinical trial was carried out at Eusebio Hernandez Hospital (Havana, Cuba. A total of 2,418 women who requested emergency contraception after unprotected coitus received either 5 mg or 10 mg mifepristone. The variables for assessing efficacy were the pregnancies that occurred and the fraction of pregnancies that were prevented. Other variables assessed were the side effects of mifepristone, vaginal bleeding, and changes in the date of the following menstruation. Results: There were 15/1,206 (1.2% and 9/1,212 (0.7% pregnancies in the 5 mg and 10 mg group, respectively (P=0.107. There were 88% and 93% prevented pregnancies in the 5 mg and 10 mg group, respectively. The side effect profiles were similar in both groups. Delayed menstruation ≥7 days was experienced by 4.9% and 11.0% of subjects in the 5 mg and 10 mg group, respectively (P=0.001. There was a significant high failure rate for women weighing >75 kg in the 5 mg group. Conclusion: It would be advisable to use the 10 mg dose of mifepristone for emergency contraception as there was a trend suggesting that the failure rate of the larger dose was lower. Keywords: mifepristone, emergency contraception

  16. Hydrogenation Effect on Mg/Co Multilayer Thin Films

    M. K. JANGID


    Full Text Available Multilayer Mg/Co thin films have been prepared using thermal evaporation method at pressure 10-5torr. Annealing of structure has been performed in atmospheric condition at 600 K constant temperature for one hour. Hydrogenation of annealed thin films has been performed by keeping these in hydrogenation cell at different hydrogen pressures for 30 min. The UV–VIS absorption spectra of thin films have been carried out at room temperature in the wavelength range of 300–800 nm. The optical band gap was found to be increase and conductivity has been found to be decreased with hydrogen pressure. The relative resistivity varies nonlinearly with time and increases with hydrogen pressure. Raman spectra of these sample shows decreasing intensity of peaks with hydrogenation. These results suggested that multilayer Mg/Co thin films structures can be used for hydrogen storage as well as solar collector materials.

  17. Increasing nitrogen rates in rice and its effect on plant nutrient composition and nitrogen apparent recovery

    Juan Hirzel


    Full Text Available Rice (Oryza sativa L. is one of the essential foods of the human diet; advances in agronomic crop management can improve productivity and profitability as well as reduce adverse environmental impacts. Nitrogen rates in Chile are generally based on crop yield without considering other agronomic factors. The objective of this experiment was to determine the effect of increasing N rates on plant nutrient composition and N apparent recovery in rice cultivated in five different locations in Chile. The five sites located in central Chile belong to one of the following soil orders: Inceptisol, Alfisol, and Vertisol; they were cropped in field conditions with 'Zafiro-INIA' rice fertilized with 0, 80, and 160 kg N ha-1. Whole-plant total DM, macronutrient composition, and N apparent recovery efficiency (NARE were determined at grain harvest. Results indicate that all evaluated parameters, with the exception of K concentration, were affected by the soil used. Nitrogen rates only affected total DM production and P, K, and Mg concentrations in plants. Phosphorus and K response decreased when N was added to some soils, which is associated with its chemical properties. Magnesium concentration exhibited an erratic effect, but it was not affected by the N rate in most soils. Nitrogen apparent recovery efficiency was not affected by the N rate and accounted for approximately 49% and 41% for 80 and 160 kg N ha-1, respectively. Macronutrient composition was 5.1-7.7 g N, 1.3-1.8 g P, 5.4-10.8 g K, 1.68-2.57 g Ca, and 0.81-1.45 g Mg kg-1 of total DM.

  18. The reactive Mg-liquid infiltration to obtain long superconducting MgB$_{2}$ cables

    Giunchi, G


    An alternative “in situ” process to the MgB2 wire manufacturing is represented by the Reactive Mg-Liquid Infiltration (Mg-RLI) process [1], in which the precursor wire is constituted by a metallic sheath encasing a central Mg rod, surrounded by the B powders. We demonstrated that this peculiar “internal Mg” assembly is able to produce very dense superconducting material of high critical current density, with an acceptable fill factor, up to 0.28. Furthermore the Mg-RLI allows also to easily dope the MgBB2 material either by carbon or nanoSiC powders. In order to realize long cables with this technique, two different approaches may be applied. The first one relies on the assembly of thin wires, fine enough that the liquid Mg cannot freely percolate along the wire during the reaction, and the second one relies on the assembly of thick hollow wires, reacted with a continuous supply of Mg to avoid deficiency of Mg in some part of the precursor wire. Both techniques have been demonstrated feasible and the ...

  19. The Interplay of Al and Mg Speciation in Advanced Mg Battery Electrolyte Solutions.

    See, Kimberly A; Chapman, Karena W; Zhu, Lingyang; Wiaderek, Kamila M; Borkiewicz, Olaf J; Barile, Christopher J; Chupas, Peter J; Gewirth, Andrew A


    Mg batteries are an attractive alternative to Li-based energy storage due to the possibility of higher volumetric capacities with the added advantage of using sustainable materials. A promising emerging electrolyte for Mg batteries is the magnesium aluminum chloride complex (MACC) which shows high Mg electrodeposition and stripping efficiencies and relatively high anodic stabilities. As prepared, MACC is inactive with respect to Mg deposition; however, efficient Mg electrodeposition can be achieved following an electrolytic conditioning process. Through the use of Raman spectroscopy, surface enhanced Raman spectroscopy, (27)Al and (35)Cl nuclear magnetic resonance spectroscopy, and pair distribution function analysis, we explore the active vs inactive complexes in the MACC electrolyte and demonstrate the codependence of Al and Mg speciation. These techniques report on significant changes occurring in the bulk speciation of the conditioned electrolyte relative to the as-prepared solution. Analysis shows that the active Mg complex in conditioned MACC is very likely the [Mg2(μ-Cl)3·6THF](+) complex that is observed in the solid state structure. Additionally, conditioning creates free Cl(-) in the electrolyte solution, and we suggest the free Cl(-) adsorbs at the electrode surface to enhance Mg electrodeposition.

  20. Effect of Ni on Mg based hydrogen storage alloy Mg3Nd

    TONG Yanqing; OUYANG Liuzhang; ZHU Min


    Magnesium-neodymium based alloys were prepared by induction melting in an alumina crucible under protection of pure argon atmosphere. XRD patterns show that the as-melted Mg-Nd and Mg3NdNi 0.1 diffraction peaks can be excellently indexed with D03 structure (BiF3 type, space group Fm3m ). The lattice constant of Mg3Nd phase is 0.7390 nm, which is determined by XRD analysis using Cohen's extrapolation method. The reversible hydrogen storage capacity reaches 1.95wt.% for Mg3Nd and 2.68wt.% for Mg3NdNi0.1 . The desorption of hydrogen takes place at 291 ℃ for Mg3Nd and at 250 ℃ for Mg3NdNi 0.1 . The alloys could absorb hydrogen at room temperature with rapid hydriding and dehydriding kinetics after only one cycle. The enthalpy (ΔH ) and entropy (ΔS ) of Mg3Nd-H dehydriding reaction were -68.2 kJ·mol-1 H2 and -0.121 kJ·(K·mol)-1 H2 determined by using van't Hoff plot according to the pressure-composition-isotherms (P-C-I) curve measured at different temperatures. Hydrogen absorption kinetic property of Mg3NdNi 0.1 alloy was also measured at room temperature.

  1. Comparing Doping Methodologies in Mg2Si/AgMg System

    Polymeris, G. S.; Theodorakakos, A.; Mars, K.; Godlewska, E.; Lioutas, Ch. B.; Hatzikraniotis, E.; Paraskevopoulos, K. M.


    Morphological and optical characterizations for the Mg2Si samples doped with Ag are presented. Two different doping methodologies with silver, namely in situ and ex situ doping, were studied for the case of Mg2Si of self-propagating high-temperature synthesis. Electron microscopy measurements in both scanning and transmission configurations verified the presence of AgMg precipitates embedded in the Mg2Si matrix and similar results were also yielded by FTIR spectroscopy. Finally, the dependence of silver content in both forms of dopant and inter-metallic constituent is studied upon doping technology.

  2. Preparation and hydrogen sorption properties of Mg-Cu-Y-H systems

    LI Zhinian; LIU Xiaopeng; HUANG Zuo; JIANG Lijun; WANG Shumao


    Mg-xwt.%CuY (x=15, 20, 25) composites were successfully prepared by reactive mechanical alloying (RMA).X-ray diffraction (XRD) measurement shows that main phases of the as milled composites are MgH2 and Mg2Cu, and they converted into Mg and MgCu2 after dehydrogenation, respectively.Pressure-Composition-Isotherm (PCI) test shows that the composites exhibit double pressure plateau at each isothermal desorption process.The hydrogen absorption and desorption kinetics of the composites become worse with increasing x content, indicating that Mg-Cu phase has a negative effect on the hydrogen sorption properties of the composites.It is supposed that the good hydrogen sorption properties of the composites attribute to the catalyst effect of yttrium hydride distributed in Mg substrate and the particles size reduction and crystal defects formed by RMA.

  3. Effects of RE on the Microstructure of Mg-8Zn-4Al Magnesium Alloys


    The effects of RE on the microstrcture of as-cast Mg-8Zn-4Al magnesium alloys were investigated. The results show that the solidification range of Mg-8Zn-4Al-xRE alloys increases with RE additions. A binary eutectic reaction can arise and produce a new phase (Mg3Al4Zn2RE) and the temperature of phase transformation point of the new phase is 412.85C. In Mg-8Zn-4Al-1.5RE alloy, a small amount of Mg3Al4Zn2RE phase and ε phases are found besides α(Mg),ψ and τ phases. Also microstructures of Mg-8Zn-4Al alloys can be refined by addition of 1.5 % RE obviously.

  4. Homogenization of alloys in the system Al-Mg-Sc

    Drits, M. E.; Toropova, L. S.; Bykov, Yu. G.


    A reduction in homogenizing anneal temperature and a reduction in soaking time leads to an increase in yield point for alloys of the system Al-Mg-Sc. The optimum homogenizing schedule for alloys of this system is heating to 400°C and soaking for up to 10 h. This homogenizing schedule provides an alloy structure of fine coherent ScAl3-phase precipitates and dissolution of excess β-phase precipitates.

  5. Synthesis and characterization of Mn intercalated Mg-Al hydrotalcite.

    Yang, Chengxue; Liao, Libing; Lv, Guocheng; Wu, Limei; Mei, Lefu; Li, Zhaohui


    Mn intercalated hydrotalcite was prepared using a reconstruction method. And Mn intercalation was confirmed by XRD, FTIR, and thermal analyses. The different valences of Mn were present as determined by XPS. Calcination slightly promoted the isomorphic replacement of Mn(2+) and Mn(3+) for Mg(2+) and Al(3+), especially the replacement of Mn(2+) for Mg(2+) and Al(3+), and to some extent, reduced Mn intercalation. Ultrasonic treatment significantly increased Mn intercalation in permanganate form (Mn(7+)), and promoted the replacement of Mn(2+) for Mg(2+) and Al(3+). XRF analysis showed that ultrasonic treatment decreased the unbalanced layer charge of Mn intercalated hydrotalcite, while prolonged calcination increased it. These results may provide guidance on the preparation and application of Mn intercalated hydrotalcite. Extended calcination time and ultrasonic vibration increased the interlayer spacing of hydrotalcite, as a result of reduction in layer charge. As the layer charge was not completely balanced after Mn intercalation, a certain amount of CO3(2-) was re-adsorbed into the interlayer space. Mn-hydrotalcites with different layer charges, different contents of Mn with varying valences are expected to have different performances in the process of adsorption, degradation, and catalysis.

  6. Strain assisted electrocaloric effect in PbZr0.95Ti0.05O3 films on 0.7Pb(Mg1/3Nb2/3)O3-0.3PbTiO3 substrate

    Zuo, Zhenghu; Chen, Bin; Wang, Baomin; Yang, Huali; Zhan, Qingfeng; Liu, Yiwei; Wang, Junling; Li, Run-Wei


    Solid state cooling technologies based on electrocaloric, magnetocaloric and mechanocaloric effects have received much attention during the past decade. To further improve the cooling efficiency and reduce the driving field, it is desirable to combine multiple effects in a single system. Here, we report on the caloric effects induced by both electric field and strain in PbZr0.95Ti0.05O3 films deposited on 0.7Pb(Mg1/3Nb2/3)O3-0.3PbTiO3 substrate. The isothermal entropy change (ΔS) induced by the antiferroelectric-ferroelectric phase transition of PbZr0.95Ti0.05O3 films is calculated to be 6.78 J K-1 kg-1. Furthermore, the strain from 0.7Pb(Mg1/3Nb2/3)O3-0.3PbTiO3 substrate can reduce the electric field where ΔS reaches the maximum by as much as 50 kV/cm. The electrocaloric efficiency is also increased from 0.366 to 0.378 by the strain effect. The electrocaloric effect in an antiferroelectric material assisted by strain may lead to more efficient solid state cooling technology.

  7. Effect of Mg-Nb oxides addition on hydrogen sorption in MgH{sub 2}

    Rahman, M.W.; Castellero, A. [Dipartimento di Chimica IFM, NIS Centre of Excellence, Universita di Torino, Via Pietro Giuria 9, 10125 Torino (Italy); Enzo, S. [Dipartimento di Chimica, Universita di Sassari, 07100 Sassari (Italy); Livraghi, S.; Giamello, E. [Dipartimento di Chimica IFM, NIS Centre of Excellence, Universita di Torino, Via Pietro Giuria 9, 10125 Torino (Italy); Baricco, M., E-mail: [Dipartimento di Chimica IFM, NIS Centre of Excellence, Universita di Torino, Via Pietro Giuria 9, 10125 Torino (Italy)


    Highlights: > H{sub 2} sorption reactions in MgH{sub 2} with 1 mol% MgNb{sub 2}O{sub 6}, Mg{sub 4}Nb{sub 2}O{sub 9} and Mg{sub 3}Nb{sub 6}O{sub 11} have been investigated. > Ball-milled samples showed the presence of a mixture of {beta} and {gamma} allotropes of MgH{sub 2}. > The presence of Mg-Nb oxides significantly accelerates the hydrogen absorption and desorption processes. > Experimental results are discussed on the basis of thermodynamic and kinetic arguments. - Abstract: H{sub 2} absorption and desorption reactions in MgH{sub 2} promoted by ball-milling with 1 mol% MgNb{sub 2}O{sub 6}, Mg{sub 4}Nb{sub 2}O{sub 9} and Mg{sub 3}Nb{sub 6}O{sub 11} have been investigated. MgH{sub 2} was milled with the bare oxides for 12 h under a high purity Ar atmosphere. Absorption and desorption reactions in the ball-milled samples were studied by in situ X-ray diffraction (XRD) in isothermal conditions with Anton Paar XRK 900 reaction chamber. XRD patterns for absorption were recorded at 573 K under hydrogen pressure of 0.9 MPa and for desorption at 623 K in vacuum. Experimental data were analysed according to the Rietveld method. Ball-milled samples showed the presence of a mixture of {beta} and {gamma} allotropes of MgH{sub 2}, with significantly broadened diffraction peaks due to reduced crystallite size and strain, together with bare additives. The presence of Mg-Nb oxides significantly accelerates the hydrogen absorption and desorption processes. The amount of hydrogen absorbed in the presence of Mg-Nb-O phases is lower than the maximum stoichiometric capacity, because of the presence of a non-reactive MgO layer on the surface of the powders or at the grain boundaries. Experimental results are discussed on the basis of thermodynamic and kinetic arguments.

  8. Hepatic autoregulation: response of glucose production and gluconeogenesis to increased glycogenolysis.

    Staehr, Peter; Hother-Nielsen, Ole; Beck-Nielsen, Henning; Roden, Michael; Stingl, Harald; Holst, Jens J; Jones, Paul K; Chandramouli, Visvanathan; Landau, Bernard R


    The effect of increased glycogenolysis, simulated by galactose's conversion to glucose, on the contribution of gluconeogenesis (GNG) to hepatic glucose production (GP) was determined. The conversion of galactose to glucose is by the same pathway as glycogen's conversion to glucose, i.e., glucose 1-phosphate --> glucose 6-phosphate --> glucose. Healthy men (n = 7) were fasted for 44 h. At 40 h, hepatic glycogen stores were depleted. GNG then contributed approximately 90% to a GP of approximately 8 Galactose, 9 g/h, was infused over the next 4 h. The contribution of GNG to GP declined from approximately 90% to 65%, i.e., by approximately 2 The rate of galactose conversion to blood glucose, measured by labeling the infused galactose with [1-(2)H]galactose (n = 4), was also approximately 2 The 41st h GP rose by approximately 1.5 and then returned to approximately 9, while plasma glucose concentration increased from approximately 4.5 to 5.3 mM, accompanied by a rise in plasma insulin concentration. Over 50% of the galactose infused was accounted for in blood glucose and hepatic glycogen formation. Thus an increase in the rate of GP via the glycogenolytic pathway resulted in a concomitant decrease in the rate of GP via GNG. While the compensatory response to the galactose administration was not complete, since GP increased, hepatic autoregulation is operative in healthy humans during prolonged fasting.

  9. First-principles calculation of dehydrogenating properties of MgH2-V systems

    ZHOU; Dianwu; PENG; Ping; LIU; Jinshui


    Based on experimental results in which VH0.81/MgH2 interface was found during the process of mechanically milling MgH2+5at%V nanocomposite, a VH/MgH2 interface is designed and constituted in this work. A first-principles plane-wave pseudopotential method based on Density Functional Theory (DFT) has been used to investigate the vanadium alloying effects on the dehydrogenating properties of magnesium hydride, i.e., MgH2. A low absolute value of the negative heat of formation of VH/MgH2 interface compared with that of MgH2 indicates that vanadium hydrides befit to improve the dehydrogenating properties of MgH2. Based on the analysis of the density of states (DOS) and the total valence electron density distribution of MgH2 before and after V alloying, it was found that the improvement of the dehydrogenating properties of MgH2 caused by V alloying originates from the increasing of the valence electrons at Fermi level (EF) and the decreasing of the HOMO-LUMO gap (△EH-L) after V alloying. The catalysis effect of V on dehydrogenating kinetics of MgH2 may attribute to a stronger bonding between V and H atoms than that between Mg and H atoms, which leads to nucleation of the α-Mg at the VH/MgH2 interface in the MgH2-V systems easier than that in pure MgH2 phase.

  10. Properties Of MgB2/Ga Composites Prepared By Mechanical Alloying

    Yoon K.


    Full Text Available In this study, we examined the effect of Ga-doping and mechanical alloying in MgB2 on microstructural and phase evolution. A comparison was made between in-situ and ex-situ processed Mg-B-Ga samples. Densification was markedly improved by ex-situ sintering of ball-milled MgB2+Ga. The Ga-doping and ball-milling prior to sintering resulted in the formation of impurity phases such as MgO, Ga5Mg2 and Ga2O3. Lattice parameter of MgB2 increased with increasing ball-milling duration as well as by Ga-doping.

  11. Preparation of an additive-free sample with a MgH2 phase by planetary ball milling of Mg with10 wt% MgH2

    Hong, Seong-Hyeon; Song, Myoung Youp


    In order to prepare an additive-free sample with a MgH2 phase, 90 wt% Mg+10 wt% MgH2 (named Mg-10MgH2) was milled under hydrogen atmosphere in a planetary ball mill for different durations (2 h, 5 h, and 10 h). The hydrogen absorption and release properties of the prepared samples were investigated and compared with those of purchased pure MgH2 samples. Mg-10MgH2 milled for 5 h had the largest quantity of hydrogen released at 648 K for 100 min of 5.96 wt%. Mg-10MgH2 milled for 5 h released 0.11 wt% H for 10 min, 4.85 wt% H for 30 min, and 5.83 wt% H for 60 min at 648 K at the first cycle. Mg-10MgH2 milled for 5 h absorbed 5.39 wt% H for 5 min and 5.92 wt% H for 60 min at 648 K at the second cycle. Dehydriding curves were also obtained at the first cycle of Mg-10MgH2 samples milled for 5 h using Mg powder with or without sieving (200 mesh). The dehydriding curve at 648 K of a Mg-10MgH2 sample milled for 5 h in the planetary ball mill was compared with that of the sample milled for 24 h in a horizontal ball mill.

  12. Cathodoluminescence study of Mg activation in non-polar and semi-polar faces of undoped/Mg-doped GaN core-shell nanorods

    Hortelano, V.; Martínez, O.; Cuscó, R.; Artús, L.; Jiménez, J.


    Spectrally and spatially resolved cathodoluminescence (CL) measurements were carried out at 80 K on undoped/Mg-doped GaN core-shell nanorods grown by selective area growth metalorganic vapor phase epitaxy in order to investigate locally the optical activity of the Mg dopants. A study of the luminescence emission distribution over the different regions of the nanorods is presented. We have investigated the CL fingerprints of the Mg incorporation into the non-polar lateral prismatic facets and the semi-polar facets of the pyramidal tips. The amount of Mg incorporation/activation was varied by using several Mg/Ga flow ratios and post-growth annealing treatment. For lower Mg/Ga flow ratios, the annealed nanorods clearly display a donor-acceptor pair band emission peaking at 3.26-3.27 eV and up to 4 LO phonon replicas, which can be considered as a reliable indicator of effective p-type Mg doping in the nanorod shell. For higher Mg/Ga flow ratios, a substantial enhancement of the yellow luminescence emission as well as several emission subbands are observed, which suggests an increase of disorder and the presence of defects as a consequence of the excess Mg doping.

  13. Obtention of Al-Mg alloys of porous morphology; Obtencion de aleaciones Al-Mg de morfologia porosa

    Barragan V, J.; Zamora R, L.; Sandoval J, A.R.; Iturbe G, J.L. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico)


    With the objective of using it as fuel cell, a Mg{sub 25}AI alloy of porous morphology was obtained. The material it was hydrogenates at 200 C by different time. It was analyzed by Scanning Electron Microscopy SEM and X-ray diffion, XRD. Those XRD diffractographs present peaks run toward the origin, that which indicates a volume increase of the unitary cell by effect of the hydrogen absorption. (Author)

  14. MgH2+20%(w)MgTiO3复合材料的吸/放氢性能%Hydriding/Dehydriding Properties of an MgH2+20%(w) MgTiO3 Composite

    王家盛; 韩树民; 李媛; 沈娜; 张伟


    为了降低MgH2的吸放氢温度,提高其吸放氢动力学性能,本文通过球磨方法制备了MgH2+20%(w) MgTiO3复合储氢材料,并研究了其储氢性能. X射线衍射(XRD)结果表明, MgTiO3在与MgH2球磨过程中生成Mg2TiO4和TiO2,并且Mg2TiO4和TiO2在体系的吸放氢过程中保持稳定,能够对MgH2的吸放氢过程产生催化作用.程序升温脱附和吸/放氢动力学测试结果表明,添加MgTiO3后MgH2的初始放氢温度从389°C降至249°C.150°C下的吸氢量从0.977%(w)提高到2.902%(w),350°C下的放氢量从2.319%(w)提高到3.653%(w).同时, MgH2放氢反应的活化能从116 kJ∙mol-1降至95.7 kJ∙mol-1.与MgH2相比, MgH2+20%(w) MgTiO3复合材料的热力学与动力学性能均有显著提高,这主要是由于球磨和放氢过程中原位生成的TiO2和Mg2TiO4具有良好的催化活性.%With the aim of decreasing the dehydriding temperature and improving the hydriding/dehydriding kinetic properties of MgH2, we prepared MgH2+20%(w) MgTiO3 composite via bal-mil ing, and investigated the hydrogen storage properties of the composite. X-ray diffraction (XRD) results showed that the MgTiO3 decomposed into Mg2TiO4 and TiO2 during the bal-mil ing. These two resulting compounds remained stable during the hydriding/dehydriding processes, working as catalysts for the hydriding/dehydriding. Temperature-programmed-desorption (TPD) and hydriding/dehydriding kinetics tests showed that doping MgH2 with MgTiO3 lowered the onset dehydrogenation temperature of MgH2 from 389 to 249 °C, as wel as increasing the hydrogen absorption amount from 0.977%(w) to 2.902%(w) at 150 °C, and increasing the desorption amount from 2.319%(w) to 3.653%(w) at 350 °C. The MgTiO3 additive decreased the dehydriding activation energy of MgH2 from 116 to 95.7 kJ∙mol-1. The thermodynamic and kinetic performance of the MgH2+20%(w) MgTiO3 composite was significantly improved compared with pristine MgH2, which was attributed to the high catalytic

  15. Destabilization of Mg Hydride by Self-Organized Nanoclusters in the Immiscible Mg-Ti System

    Asano, Kohta; Westerwaal, Ruud J.; Anastasopol, Anca; Mooij, Lennard P A; Boelsma, Christiaan; Ngene, Peter; Schreuders, Herman; Eijt, Stephan W H; Dam, Bernard


    Mg is an attractive hydrogen storage material not only because of its high gravimetric and volumetric hydrogen capacities but also because of it low material costs. However, the hydride of MgH2 is too stable to release hydrogen under moderate conditions. We demonstrate that the formation of

  16. Energy Bands and Fermi Surface for beta-MgMh and beta-MgTl

    Skriver, Hans Lomholt


    The energy bands of ordered β′-MgHg and β′-MgTl have been calculated by the relativistic linear-muffintin-orbital method. We show how the gross features of the energy bands may be estimated from Wigner-Seitz rules. The densities of states are calculated and the heat capacities derived. The Fermi...

  17. Destabilization of Mg Hydride by Self-Organized Nanoclusters in the Immiscible Mg-Ti System

    Asano, Kohta; Westerwaal, Ruud J.; Anastasopol, Anca; Mooij, Lennard P A; Boelsma, Christiaan; Ngene, Peter; Schreuders, Herman; Eijt, Stephan W H; Dam, Bernard


    Mg is an attractive hydrogen storage material not only because of its high gravimetric and volumetric hydrogen capacities but also because of it low material costs. However, the hydride of MgH2 is too stable to release hydrogen under moderate conditions. We demonstrate that the formation of nanomete

  18. Maslinic acid added to the diet increases growth and protein-turnover rates in the white muscle of rainbow trout (Oncorhynchus mykiss).

    Fernández-Navarro, Mónica; Peragón, Juan; Amores, Victoria; De La Higuera, Manuel; Lupiáñez, José Antonio


    Maslinic acid (2-alpha, 3-beta-dihydroxiolean-12-en-28-oic acid) is a triterpenoid compound present in fruit and leaves of Olea europaea that can be used as an additive in the diet of trout. The present work investigates the effects of maslinic acid on growth, protein-turnover rates and nucleic acid concentration in trout white muscle. Five groups of 180 trout of a mean body mass of 20 g were fed for 225 days with diets containing 0, 1, 5, 25 and 250 mg of maslinic acid per kg of diet. At the end of the experiment, white-muscle weight and protein-accumulation rate of trout fed with maslinic acid were higher than in control. The total content of DNA, RNA, and protein in trout fed with 25 and 250 mg of maslinic acid kg(-1) were significantly higher than in control. The protein:DNA ratio was also slightly higher than control. In the same groups of trout, fractional (K(S)) and absolute (A(S)) protein-synthesis rates increased to more than 80% over the control values while no differences were found in the fractional protein-degradation rate (K(D)). These results, similar to previous findings in liver, show that maslinic acid can act as a growth factor when added to a standard trout diet.

  19. Eu{sup 3+} luminescence properties of Eu- and Mg-codoped AlGaN

    Kanemoto, Masayoshi [Department of Electrical and Electronics Information Engineering, Toyohashi University of Technology, 1-1 Hibarigaoka, Tempaku-cho, Toyohashi 441-8580, Aichi (Japan); Sekiguchi, Hiroto, E-mail: [Department of Electrical and Electronics Information Engineering, Toyohashi University of Technology, 1-1 Hibarigaoka, Tempaku-cho, Toyohashi 441-8580, Aichi (Japan); Yamane, Keisuke [Department of Electrical and Electronics Information Engineering, Toyohashi University of Technology, 1-1 Hibarigaoka, Tempaku-cho, Toyohashi 441-8580, Aichi (Japan); Okada, Hiroshi [Electronics-Inspired Interdisciplinary Research Institute (EIIRIS), Toyohashi University of Technology, 1-1 Hibarigaoka, Tempaku-cho, Toyohashi 441-8580, Aichi (Japan); Department of Electrical and Electronics Information Engineering, Toyohashi University of Technology, 1-1 Hibarigaoka, Tempaku-cho, Toyohashi 441-8580, Aichi (Japan); Wakahara, Akihiro [Department of Electrical and Electronics Information Engineering, Toyohashi University of Technology, 1-1 Hibarigaoka, Tempaku-cho, Toyohashi 441-8580, Aichi (Japan); Electronics-Inspired Interdisciplinary Research Institute (EIIRIS), Toyohashi University of Technology, 1-1 Hibarigaoka, Tempaku-cho, Toyohashi 441-8580, Aichi (Japan)


    We investigated the effect of Mg codoping on luminescence properties of AlGaN:Eu to improve emission through synergy effect between an increase in bandgap by AlGaN and the Mg codoping technique. The luminescence properties of AlGaN:(Eu, Mg) are strongly influenced by the Mg concentration and Al composition. Mg codoping in AlGaN was observed to contribute to increasing photoluminescence (PL) integrated intensity and to improve thermal quenching from 7.3% to 60% while the dominant optical site remained site B (622.3-nm peak) with low excitation cross section. The total concentration of optically activated Eu at 25 K was a constant at for either optical site, indicating that Mg codoping did not affect the formation of optical sites. The PL decay times at room temperature (RT) increased with Mg concentration because of suppression of the back-transfer process. For optimized Mg concentration, an increase in the Al composition contributed to the total activated Eu concentration and changed the dominant optical site from A (620.3-nm peak) to B. The activation energy E{sub a}, which is the difference in energy between the {sup 5}D{sub 0} energy level and the trap level in the host material, was estimated from temperature dependence of PL decay time. The E{sub a} for site A was larger than that for site B, suggesting that the back-transfer rate for site A was less than that for site B. - Highlights: • Eu and Mg codoped AlGaN was grown on GaN template by NH{sub 3}-MBE. • The effect of Mg codoping on optical properties of Eu doped AlGaN was investigated. • Mg codoping contributed to increase PL intensity at RT and improve thermal quenching. • An increase in the Al content affected total activated N{sub Eu} and dominant optical site.

  20. Reactive wetting of amorphous silica by molten Al-Mg alloys and their interfacial structures

    Shi, Laixin; Shen, Ping; Zhang, Dan; Jiang, Qichuan


    The reactive wetting of amorphous silica substrates by molten Al-Mg alloys over a wide composition range was studied using a dispensed sessile drop method in a flowing Ar atmosphere. The effects of the nominal Mg concentration and temperature on the wetting and interfacial microstructures were discussed. The initial contact angle for pure Al on the SiO2 surface was 115° while that for pure Mg was 35° at 1073 K. For the Al-Mg alloy drop, it decreased with increasing nominal Mg concentration. The reaction zone was characterized by layered structures, whose formation was primarily controlled by the variation in the alloy concentration due to the evaporation of Mg and the interfacial reaction from the viewpoint of thermodynamics as well as by the penetration or diffusion of Mg, Al and Si from the viewpoint of kinetics. In addition, the effects of the reaction and the evaporation of Mg on the movement of the triple line were examined. The spreading of the Al-Mg alloy on the SiO2 surface was mainly attributed to the formation of Mg2Si at the interface and the recession of the triple line to the diminishing Mg concentration in the alloy.

  1. Microstructures and properties of rapidly solidified Mg-Zn-Ca alloys


    Ternary alloys based on the Mg-Zn-Ca system were produced by twin-roll rapid solidification. The alloys were characterized by OM, SEM, HRTEM, XRD, EDS and Micro-hardness. The results show that the rapidly solidified flakes are of frnedendritic cell structures with the cell size ranging from 1 to 5 μn. The Mg-6Zn-5Ca alloy in RS and annealing (200 ℃ for 1 h) states are mainly composed of α-Mg, Mg2Ca, Ca2Mg6, Zn3 and a small quantity of Mg51Zn20, MgZn2 and Mg2Zn3. Micro-hardness increases with the increment of Ca content and age hardening occurs after aging at 200 ℃ in the flakes probably due to the precipitation strengthening of the fine precipitates Mg2Ca and Ca2Mg6, Zn3. Some phases at the grain boundary in Mg-6Zn-5Ca alloy are identified by means of HRTEM, which may be beneficial to the improvement in thermal stability of the alloy.

  2. MG132 Induced Apoptosis Pathway in HL-60 Cells and Impact of Allogeneic Mixed Lymphocyte Reaction

    Yong-ming Zhou; Wei Guo; Hao Zhou; Jin-hua Zhang; Zhi-ping Liu; Mei-xia Yu


    Objective: To investigate the proteasome inhibitor MG132-induced apoptosis pathway in HL-60 cells and the role of allogeneic mixed lymphocyte reaction.Methods: Cell apoptosis was analyzed by flow cytometry. The expressions of p21 protein, p27 protein and p53 protein in HL-60 cells treated with MG132 were measured by Western blot. The proliferation of, peripheral blood mononuclear cells (PBMNCs) after treatment with 75 Gy irradiated HL-60 cells treated with MG132 was measured with CCK-8.Results: High-dose MG132 induced apoptosis in HL-60 cells. No significant change was observed in MG132-induced apoptosis after inhibiting caspase-8 and caspase-9 pathway. The expressions of p21 protein and p27 protein increased in MG132-induced apoptosis. HL-60 cells treated with low-dose MG132 improved the proliferation of PBMNCs from healthy volunteers.Conclusion: High-dose MG132 induced apoptosis and directly killed HL-60 cells. MG132 induced apoptosis in a caspase-8- and caspase-9-independent pathway. p21 protein and p27 protein were involved in MG132-induced apoptosis in HL-60 cells. HL-60 cells treated with Low-dose MG132 improved the effect of promoting the proliferation of PBMNCs from healthy volunteers.

  3. The influence of Cr and Y on the micro structural evolution of Mg-Cr-O and Mg-Y-O thin films

    Jehanathan, N., E-mail: [Electron Microscopy for Materials Research (EMAT), University of Antwerp, Groenenborgerlaan 171, 2020 Antwerpen (Belgium); Georgieva, V. [PLASMANT Research Group, Department of Chemistry, University of Antwerp, Universiteitsplein 1, 2610 Antwerpen (Belgium); Saraiva, M.; Depla, D. [Department of Solid State Sciences, Ghent University, Krijgslaan 281/S1, 9000 Ghent (Belgium); Bogaerts, A. [PLASMANT Research Group, Department of Chemistry, University of Antwerp, Universiteitsplein 1, 2610 Antwerpen (Belgium); Van Tendeloo, G. [Electron Microscopy for Materials Research (EMAT), University of Antwerp, Groenenborgerlaan 171, 2020 Antwerpen (Belgium)


    The compositional influence of Cr and Y on the microstructure of Mg-Cr-O, and Mg-Y-O films synthesized by reactive magnetron sputtering has been investigated by transmission electron microscopy, X-ray diffraction and molecular dynamics simulations. A decrease in crystallinity is observed in these films as the M (Cr or Y) content is increased. It is found that M forms a solid solution with MgO for metal ratios up to {approx} 70% and {approx} 50% for Cr and Y respectively. Above {approx} 70% Cr metal ratio the Mg-Cr-O films are found to be completely amorphous. The Mg-Y-O films are composed of Mg(Y)O and Y{sub 2}O{sub 3} nano crystallites{sub ,} up to {approx} 50% Y metal ratio. Above this ratio, only Y{sub 2}O{sub 3} nano crystallites are found. The preferential < 111> MgO grain alignment is strongly affected by the increase in M content. For M metal ratios up to {approx} 50%, there is a selective promotion of the < 100> MgO grain alignments and a decline in the < 111> grain alignments.

  4. Microstructure and hardness of Mg-based composites reinforced with Mg2Si particles

    Mustafa Aydin; Cem Ozgür; Osman San


    Magnesium powders were mechanically alloyed with SiO2 powder particles having different particle sizes using high-energy ball milling techniques under Ar atmosphere for 1 h. The powders were consolidated with cold pressing under 560 Mpa. They were then sintered at 550℃ for 45 min under Ar atmosphere. The composites obtained on the Mg-SiO2 system were investigated using the Archimedes principle, a differential scanning calorimeter, X-ray diffraction, optic microscopy, and scanning electron microscopy. For the mechanically alloyed powders, the solid-state reaction of the synthesis of Mg2Si and MgO progressed further during sintering of the materials. The results showed that the strengthening mechanisms were dependent on dispersion hardening of fine Mg2Si and MgO particulates dispersed homogeneously in the matrix.

  5. Growth of MgO on multi-layered graphene and Mg in PVA matrix

    Marka, Sandeep K.; Mohiddon, Md. Ahamad; Prasad, Muvva D.; Srikanth, Vadali V. S. S.


    An easy and low temperature in-situ growth of MgO micro-rods on multi-layered graphene (MLG) in poly vinyl alcohol (PVA) matrix is elucidated. MLG decked with nanosized fragments of MgO and PVA are used as the starting materials to form MgO micro-rods (width = ∼1 μm and length = ∼4 μm) and MLG filled PVA composite film. Simple solution mixing, spin coating and simple drying processes are used to obtain the PVA composite. The growth mechanism of MgO micro-rods and the role of PVA in the growth of MgO micro-rods are explained on the basis of the observed morphological, structural and phase characteristics and a further controlled synthesis experiment, respectively.

  6. Low dose Mifepristone (100 mg for medical termination of pregnancy

    Shikha Seth


    Full Text Available Background: Abortion is the most common entity in the practice of obstetrics and gynaecology. Different methods and modes have been opted for until now to find an effective regimen with the least complications. We have tried the minimal dose (100 mg of Mifepristone (PO instead of the presently recommended 200 mg for medical abortion in early first trimester cases. Objectives: The objective of the study was to determine the efficacy of low dose (100 mg Mifepristone for medical termination of early pregnancy with oral Misoprostol 800 μg, 24 hours later.Design: A prospective analytical study was conducted on a population of 82 early-pregnant patients who have requested medical abortions.Method: Pregnant women of less than 56 days gestation age from their last menstrual period, requesting medical abortion were selected over a period of 14 months from January 2007 to March 2008. They were given 100 mg Mifepristone orally on Day-1, followed by 800 μg Misoprostol orally 24 hours later on Day-2, keeping the patient in the ward for at least 6 hours. Abortion interval, success rate, post-abortion bleeding and side-effects were noted. Success was defined as complete uterine evacuation without the need for surgical intervention.Results: The total success rate of this minimal dose Mifepristone regimen was 96.25%. Pain and nausea were the predominant side-effects noted. In total 72 (90% women had completely aborted within 5 hours of taking Misoprostol. Three (3.75% women only required suction aspiration, hence termed as failed medical abortion. The abortion interval increased with the gestation age. All three failures were of the more-than-42-day gestational age group. The overall mean abortion interval was 4.68 ± 5.32 hours.Conclusion: Mifepristone 100 mg, followed 24 hours later by Misoprostol 800 μg orally, is a safe and effective regimen for medical abortion.

  7. Comparative effects of dimethoate and deltamethrin on reproductive system in male mice.

    Abdallah, F Ben; Slima, A Ben; Dammak, I; Keskes-Ammar, L; Mallek, Z


    The effects of dimethoate (5, 15 and 28 mg kg(-1) day(-1)), deltamethrin (5 mg kg(-1) day(-1)) and their mixture (5 mg kg(-1) day(-1)) on male reproduction in mice were studied. The insecticides were given orally by gavage to male mice for 21 days. At the end of the treatment period, body, testes and epididymides weights and sperm parameters were determined. Alone mixture treatment has significantly decreased body weights. Dimethoate at 28 mg kg(-1) day(-1), deltamethrin at 5 mg kg(-1) day(-1) and their mixture at 5 mg kg(-1) day(-1) were associated with a significantly decreased sperm count, motility and viability and significantly increased percent morphologically abnormal spermatozoa compared with the controls. This study demonstrated the adverse effects of dimethoate at high dose, deltamethrin and their combining at 5 mg kg(-1) day(-1) on reproductive system and sperm parameters in male mice.

  8. Study on in-situ Mg2Si/Al-Si composites with different compositions

    Jing Qingxiu; Zhang Caixia; Huang Xiaodong


    Effects of chemical composition and heat treatment on microstructures and mechanical properties of in-situ Mg2Si/Al-Si composites were investigated. It was found that, in the microstructure of an Al-5.7wt% Mg2Si composite with 8.2wt% extra Si, the binary eutectic Mg2Si locates at the grain boundaries with an undeveloped Chinese script-like morphology, and the primary α-Al is formed into a cell structure due to the selective modification effect of the modifiers of mischmetal and Strontium salt; whereas in the composite with a near Al-Mg2Si eutectic composition and little extra Si content, the intercrescence eutectic Mg2Si formed with the binary eutectic a-Al grows into integrated Chinese script-like shape. As Si content increases, the eutectic Mg2Si dendrite becomes coarser in morphology but less in volum e fraction. Hardness and tensile strength of the cast Mg2Si/Al-Si composites do not increase with increasing of Mg content, but they are related to the size and morphology of the eutectic and primary Mg2Si phases. Heat treatment with optimal parameters is an effective way to improve the properties of the in-situ composites.

  9. Mg2(Si,Sn)-based thermoelectric materials and devices

    Gao, Peng

    Thermoelectric effects are phenomena found in materials that can achieve direct conversion between heat flow and electricity. One important application of thermoelectric effects is thermoelectric generators, which can generate electricity when a temperature gradient is applied. Thermoelectric generators make use of various sources of heat and it is considered a promising solution for waste heat recovery. The conversion efficiency of thermoelectric generators depends on the materials used in the devices. Significant improvement in the performance of thermoelectric materials has been made in the past few decades. However, most of the good thermoelectric materials being investigated have limitations, such as the high materials cost, high materials density and toxicity of the constituent elements. The Mg2(Si,Sn)-based materials studied in this work are promising candidates for thermoelectric generators in the mid-temperature range and have drawn increasing research interest in recent years because these materials are high performance thermoelectrics that are low cost, low-density and non-toxic. In this work, systematic studies were performed on the Mg2(Si,Sn) thermoelectric materials. Thermal phase stability was studied for different compositions of Mg2Si1-xSnx and Mg2Si0.4Sn 0.6 was used as base material for further optimization. Both n-type and p-type samples were obtained by doping the materials with different elements. Peak ZT ˜ 1.5 for the n-type and ZT ˜ 0.7 for the p-type materials were obtained, both of which are among the best reported results so far. Experimental work was also done to study the techniques to develop the Mg2Si 0.4Sn0.6 materials into working devices. Different electrode materials were tested in bonding experiment for this compound, and copper was found to be the best electrode material for Mg2Si 0.4Sn0.6. Preliminary work was done to demonstrate the possibility of fabricating a Mg2Si0.4Sn0.6-based thermoelectric generator and the result is

  10. The catalytic reactions in the Cu-Li-Mg-H high capacity hydrogen storage system.

    Braga, M H; El-Azab, A


    A family of hydrides, including the high capacity MgH2 and LiH, is reported. The disadvantages these hydrides normally display (high absorption/desorption temperatures and poor kinetics) are mitigated by Cu-hydride catalysis. This paper reports on the synthesis of novel CuLi0.08Mg1.42H4 and CuLi0.08Mg1.92H5 hydrides, which are structurally and thermodynamically characterized for the first time. The CuLi0.08Mg1.42H4 hydride structure in nanotubes is able to hold molecular H2, increasing the gravimetric and volumetric capacity of this compound. The catalytic effect these compounds show on hydride formation and decomposition of CuMg2 and Cu2Mg/MgH2, Li and LiH, Mg and MgH2 is analyzed. The Gibbs energy, decomposition temperature, and gravimetric capacity of the reactions occurring within the Cu-Li-Mg-H system are presented for the first time. First principles and phonon calculations are compared with experiments, including neutron spectroscopy. It is demonstrated that the most advantageous sample contains CuLi0.08Mg1.92 and (Li) ∼ Li2Mg3; it desorbs/absorbs hydrogen according to the reaction, 2CuLi0.08Mg1.42H4 + 2Li + 4MgH2 ↔ 2CuLi0.08Mg1.92 + Li2Mg3 + 8H2 at 114 °C (5.0 wt%) - 1 atm, falling within the proton exchange membrane fuel cell applications window. Finally the reaction 2CuLi0.08Mg1.42H4 + MgH2 ↔ 2CuLi0.08Mg1.92 + 5H2 at 15 °C (4.4 wt%) - 1 atm is found to be the main reaction of the samples containing CuLi0.08Mg1.92 that were analyzed in this study.

  11. Mg based alloys obtained by mechanical alloying

    Ordonez, S. [Univ. de Santiago de Chile (Chile). Fac. de Ingenieria; Garcia, G.; Serafini, D.; San Martin, A.


    In the present work, we studied the production of magnesium alloys, of stoichiometry 2Mg + Ni, by mechanical alloying (MA) and the behavior of the alloys under hydrogen in a Sievert`s type apparatus. The elemental powders were milled under argon atmosphere in a Spex 8000 high energy ball mill. The milled materials were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Only minimum amounts of the Mg{sub 2}Ni intermetallic compound was obtained after 22 h of milling time. Most of the material was sticked to the inner surface of the container as well as to the milling balls. Powders milled only for 12 hours transforms to the intermetallic at around 433 K. Effects of the MA on the hydrogen absorption kinetics were also studied. (orig.) 10 refs.

  12. Bulk amorphous Mg-based alloys

    Pryds, Nini


    The present paper describes the preparation and properties of bulk amorphous quarternary Mg-based alloys and the influence of additional elements on the ability of the alloy to form bulk amorphous. The main goal is to find a Mg-based alloy system which shows both high strength to weight ratio...... and a low glass transition temperature. The alloys were prepared by using a relatively simple technique, i.e. rapid cooling of the melt in a copper wedge mould. The essential structural changes that are achieved by going from the amorphous to the crystalline state through the supercooled liquid state...... are discussed in this paper. On the basis of these measurements phase diagrams of the different systems were constructed. Finally, it is demonstrated that when pressing the bulk amorphous alloy onto a metallic dies at temperatures within the supercooled liquid region, the alloy faithfully replicates the surface...

  13. Novel alginate based coatings on Mg alloys

    Sangeetha, K.; Roy, Abhijit [Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15261 (United States); Singh, Satish [Department of Chemical Engineering, University of Pittsburgh, Pittsburgh, PA 15261 (United States); Lee, Boeun [Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15261 (United States); Kumta, Prashant N., E-mail: [Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15261 (United States); Department of Chemical Engineering, University of Pittsburgh, Pittsburgh, PA 15261 (United States); Center for Craniofacial Regeneration, University of Pittsburgh, Pittsburgh, PA 15261 (United States); Center for Complex Engineered Multifunctional Materials, University of Pittsburgh, Pittsburgh, PA 15261 (United States); Department of Mechanical Engineering and Materials Science, University of Pittsburgh, Pittsburgh, PA 15261 (United States)


    Coatings on yttrium doped magnesium (Mg4Y) alloy substrates were prepared using alginate hydrogels by dip coating method to improve the surface bioactive properties of the substrate. Furthermore, composite coatings containing nano-sized calcium phosphate corresponding to hydroxyapatite (HA) phase entrapped within alginate hydrogel were also synthesized on the Mg4Y substrates. Surface characteristics of these coated substrates have been investigated using FTIR-ATR, SEM and EDS. The results show that the coatings with alginate alone are not stable in vitro; however, incorporation of NanoCaPs slightly improves the stability of these coatings. In addition, these composite coatings showed cell attachments with fibronectin incorporation. These results indicate that alginate hydrogels have the potential to be used as bioactive coating materials for different biofunctional applications.

  14. Automotive Mg Research and Development in North America

    Carpenter, Joseph A. [U.S. Department of Energy; Jackman, Jennifer [CANMET - Materials Technology Laboratory, Natural Resources of Canada; Li, Naiyi [Ford Motor Company; Osborne, Richard J. [General Motors Corporation; Powell, Bob R. [General Motors Corporation; Sklad, Philip S [ORNL


    Expanding world economic prosperity and probable peaking of conventional petroleum production in the coming decades require efforts to increase the efficiency of, and the development of alternatives to, petroleum-based fuels used in automotive transportation. North America has been aggressively pursuing both approaches for over ten years. Mainly as a result of lower prices due to global sourcing, magnesium has recently emerged as a serious candidate for lightweighting, and thus increasing the fuel efficiency of, automotive transportation. Automotive vehicles produced in North America currently use more Mg than vehicles produced elsewhere in the world, but the amounts per vehicle are very small in comparison to other materials such as steel, aluminum and plastics. The reasons, besides price, are primarily a less-developed state of technology for Mg in automotive transportation applications and lack of familiarity by the vehicle manufacturers with the material. This paper reviews some publicly-known, recent, present and future North American research and development activities in Mg for automotive applications.

  15. Electronic structure of MgB2

    P Modak; R S Rao; B K Godwal; S K Sikka


    Results of ab initio electronic structure calculations on the compound MgB2 using the FPLAPW method employing GGA for the exchange-correlation energy are presented. Total energy minimization enables us to estimate the equilibrium volume, / ratio and the bulk modulus, all of which are in excellent agreement with experiment. We obtain the mass enhancement parameter by using our calculated (F) and the experimental specific heat data. The c is found to be 24.7 K.

  16. Orientation relationships between icosahedral clusters in hexagonal MgZn2 and monoclinic Mg4Zn7 phases in Mg-Zn(-Y) alloys

    Rosalie, Julian M.; Somekawa, Hidetoshi; Singh, Alok; Mukai, Toshiji


    Intermetallic precipitates formed in heat-treated and aged Mg-Zn and Mg-Zn-Y alloys have been investigated via electron microscopy. Coarse spheroidal precipitates formed on deformation twin boundaries contained domains belonging to either the MgZn2 hexagonal Laves phase or the monoclinic Mg4Zn7 phase. Both phases are structurally related to the quasi-crystalline phase formed in Mg-Zn-Y alloys, containing icosahedrally coordinated zinc atoms arranged as a series of broad rhombohedral units. This rhombohedral arrangement was also visible in intragranular precipitates where local regions with the structures of hexagonal MgZn2 and Mg4Zn7 were found. The orientation adopted by the MgZn2 and Mg4Zn7 phases in twin-boundary and intragranular precipitates was such that the icosahedral clusters were aligned similarly. These results highlight the close structural similarities between the precipitates of the Mg-Zn-Y alloy system.

  17. Interstitial Fe in MgO

    Mølholt, T E; Gunnlaugsson, H P; Svane, A; Masenda, H; Naidoo, D; Bharuth-Ram, K; Fanciulli, M; Gislason, H P; Johnston, K; Langouche, G; Ólafsson, S; Sielemann, R; Weyer, G


    Isolated Fe-57 atoms were studied in MgO single-crystals by emission Mossbauer spectroscopy following implantation of Mn-57 decaying to Fe-57. Four Mossbauer spectral components were found corresponding to different Fe lattice positions and/or charge states. Two components represent Fe atoms substituting Mg as Fe2+ and Fe3+, respectively; a third component is due to Fe in a strongly implantation-induced disturbed region. The fourth component, which is the focus of this paper, can be assigned to Fe at an interstitial site. Comparison of its measured isomer shift with ab initio calculations suggests that the interstitial Fe is located on, or close to, the face of the rock-salt MgO structure. To harmonize such an assignment with the measured near-zero quadrupole interaction a local motion process (cage motion) of the Fe has to be stipulated. The relation of such a local motion as a starting point for long range diffusion is discussed.

  18. Using elevated CO2 to increase the biomass of a Sorghum vulgare x Sorghum vulgare var. sudanense hybrid and Trifolium pratense L. and to trigger hyperaccumulation of cesium.

    Wu, Huibin; Tang, Shirong; Zhang, Ximei; Guo, Junkang; Song, Zhengguo; Tian, Shuai; Smith, Donald L


    The most important challenge to use phytoremediation is how to improve its efficiency by increasing the accumulation of metals in plants, or by improving key plant biological traits that should enhance metal uptake. In this paper, we used open-top chambers to investigate the effects of elevated CO2 (860 microL L(-1)) on biomass and Cs uptake by a Sorghum vulgare x Sorghum vulgare var. sudanense hybrid and Trifolium pratense L. growing on soils spiked with various levels of cesium (0, 300, 1500 and 3000 mg Cs kg(-1)). The results showed that elevated CO2 not only increased aboveground biomass of the Sorghum and Trifolium species by 32-111%, and by 8-11%, respectively, compared to the ambient CO2 treatment, but also caused more accumulation of Cs by Sorghum species (up to 73%) than Trifolium species (up to 43%). It was speculated that the increase in biomass and the improvement in Cs accumulation ability at elevated CO2 could be related to lowered soil pH values, and changes in number and kind of microorganisms in the rhizospheres of the two tested species. This is the first report of a link among elevated CO2, increased biomass and hyperaccumulation of Cs by Sorghum and Trifolium species.

  19. DHEA and non-alcoholic fat liver disease: increased gene expression of peroxisome proliferation-activated receptor γ (PPARγ and fatty acid synthase (FAS

    Felipe Natali Almeida


    Full Text Available Dehydroespiandrosterone (DHEA is associated with improvements in chronic degenerative diseases, including obesity, insulin resistance, and cardiovascular diseases. Nevertheless, it is observed an increase in its concentration in individuals with liver lipid infiltration, but it is not precise if this condition emerges as a cause or a consequence. In this way, we aimed to identify gene expression alterations in lipid and glucose liver metabolism markers, as well as oxidative stress markers. For this purpose, male Wistar rats, 12-14 months old were treated with subcutaneous injections of DHEA (only dose of 10 mg kg-1; and after 7 days, hepatic gene expression by PCR real time were performed for the following genes:  G6Pase, PEPCK, FAS, PPARγ, malic enzyme, ChREBP, LXR, catalase, GPx, iNOS, NADPH oxidase subunits and PCNA. We observed a tendency of reduction in G6Pase gene expression in treated group (p = 0.08. In addition, it was identified an increase in liver PPARγ and FAS gene expressions, two markers of increased activity of lipogenic pathway. We also observed an increase in iNOS gene expression, a known inductor of systemic and hepatic insulin resistance. In conclusion, our data indicates that the treatment with DHEA can be associated with the development of liver lipid infiltration and hepatic insulin resistance.

  20. Midazolam 12 mg is moderately counteracted by 250 mg caffeine in man.

    Mattila, M J; Vainio, P; Nurminen, M L; Vanakoski, J; Seppälä, T


    Caffeine (Caf) counteracts various effects of benzodiazepines (BZDs). Since the effects of zolpidem, a short-acting atypical GABA(A)-BZD agonist, were not antagonized by Caf, we studied an interaction between Caf and midazolam (Mid) in healthy volunteers. In Study 1, 108 healthy students divided to 6 parallel groups were given Mid 12 mg (capsule) and Caf 125 and 250 mg (in decaffeinated coffee), alone and in combinations in the double-blind placebo-controlled manner. Objective and subjective tests were done before and at 45 and 90 min after intake. Ranked delta-values (changes from baseline) were analyzed by one-way contrast ANOVA and Scheffe's tests. In Study 2, six healthy subjects took Mid 15 mg (tablet) with and without Caf 300 mg. The dynamic effects were analyzed as in Study 1 and the plasma concentrations were assayed. In Study 1, learn effects after placebo (ad + 15%) were seen for letter cancellation and digit symbol substitution tests. Midazolam alone significantly (p 0.05). In conclusion, in a parallel group study, sedative effects of Mid 12 mg were only moderately antagonized by Caf 250 mg but not by Caf 125 mg. In a cross-over study, a weak interaction was found subjectively but not in objective measures.

  1. Unravelling Mg2+-RNA binding with atomistic molecular dynamics.

    Cunha, Richard A; Bussi, Giovanni


    Interaction with divalent cations is of paramount importance for RNA structural stability and function. We here report a detailed molecular dynamics study of all the possible binding sites for Mg(2+) on a RNA duplex, including both direct (inner sphere) and indirect (outer sphere) binding. In order to tackle sampling issues, we develop a modified version of bias-exchange metadynamics which allows us to simultaneously compute affinities with previously unreported statistical accuracy. Results correctly reproduce trends observed in crystallographic databases. Based on this, we simulate a carefully chosen set of models that allows us to quantify the effects of competition with monovalent cations, RNA flexibility, and RNA hybridization. Our simulations reproduce the decrease and increase of Mg(2+) affinity due to ion competition and hybridization respectively, and predict that RNA flexibility has a site dependent effect. This suggests a non trivial interplay between RNA conformational entropy and divalent cation binding.

  2. Microstructure, cold rolling, heat treatment, and mechanical properties of Mg-Li alloys

    Haibin Ji; Guangchun Yao; Hongbin Li


    The magnesium-lithium (Mg-Li) alloy exhibits two phase structures between 5.7wt% and 10.3wt% Li contents, consisting of the a (hcp) Mg-rich and the β (bee) Li-rich phases, at room temperature. In the experiment, Mg-5Li-2Zn, Mg-9Li-2Zn,Mg-16Li-2Zn, Mg-22Li-2Zn, Mg-5Li-2Zn-2Ca, Mg-9Li-2Zn-2Ca, Mg-16Li-2Zn-2Ca, and Mg-22Li-2Zn-2Ca (wt%) were melted.During the melting process, the flux, which was composed of lithium chloride (LiCI) and lithium fluoride (LiF) in the proportion of 3:1 (mass ratio) and argon gas were used to protect the alloys from oxidation. The mierostructure, mechanical properties, and cold-rolling workability of the wrought alloys were studied. The crystal grain of the alloys (adding Ga) is fine. The hardness of the studied alloys decreases with an increase in element Li. The density of the studied alloys is in the range of 1.187 to 1.617 g/cm3 The reduction of the Mg-16Li-2Zn and Mg-22Li-2Zn alloys can exceed 85% at room temperature. The Mg-9Li-2Zn-2Ca alloy was heat treated at 300℃ for 8, 12, 16, and 24 h, respectively. The optimum heat treatment of the Mg-9Li-2Zn-2Ca alloy is 300~Cx12h by metallographic observation and by studying the mechanical properties of the alloys.

  3. Effect of Adding Elements on Microstructure of Mg-3Si Alloy

    CUI Bin


    Full Text Available The microstructure of alloy Mg-3Si(mass fraction/%, same as below after successive additions with different elements of Zn, Nd, Gd and Y was observed and the microstructure evolution was investigated by scanning electron microscopy and X-ray diffraction. The results show the primary Mg2Si particles co-exist with eutectic Mg2Si particles in binary alloy Mg-Si. With minor addition of Zn element, only primary Mg2Si can be found in ternary Mg-3Si-3Zn system while eutectic Mg2Si particles disappear. In quaternary alloy Mg-2.0Nd-3.0Zn-3.0Si, the addition of Nd element can effectively refine the primary Mg2Si particles and form some Mg41Nd5 particles. After continuous adding of Gd and Y elements into quaternary system, Gd5Si3 and YSi particles increase significantly in the alloy Mg-8.0Gd-4.0Y-2.0Nd-3.0Zn-3.0Si, while volume fraction of primary Mg2Si decrease significantly. Thermo-Calc calculation predicts that the Gibbs free energy for primary particles Gd5Si3, YSi is lower, and therefore Gd, Y atom and Si are more likely to form compounds. In Mg-8Gd-4Y-2Nd-3Zn-3Si alloy, room temperature Gibbs free energy for primary particles Mg2Si, Gd5Si3, YSi is -9.56×104, -8.72×104, -2.83×104J/mol, respectively, and the mass fraction of these particles is 8.07%, 5.27%, 1.40% respectively.

  4. Zolpidem 10 mg given at daytime is not antagonized by 300 mg caffeine in man.

    Mattila, M J; Nurminen, M L; Vainio, P; Vanakoski, J


    Caffeine counteracts various effects of traditional benzodiazepines (BZDs). As zolpidem, a short-acting hypnotic, is an atypical GABAA-BZD agonist, we investigated when caffeine would counteract the effects of zolpidem as well. In daytime study I, zolpidem 10 mg (capsule) and caffeine 150 or 300 mg (in decaffeinated coffee) were given, alone and in combinations, to parallel groups (n = 15-17) of healthy students in double-blind and placebo-controlled manner. Objective and subjective tests were done before and 45 min and 90 min after intake. Ranked delta values (changes from baseline) were analysed by one-way contrast ANOVA and Scheffe's tests. In daytime study II, four healthy subjects took zolpidem 10 mg alone, and together with blinded caffeine 250 mg or (at -45 min) erythromycin 750 mg. Objective and subjective effects were measured and plasma zolpidem concentrations assayed at baseline and 45 min and 90 min after zolpidem intake. In study I, practice effects after placebo (ad + 30%) were seen for letter cancellation and digit symbol substitution but not for flicker fusion tests. Zolpidem alone significantly impaired (P effects of zolpidem and either dose of caffeine matched those measured after zolpidem alone. Zolpidem + caffeine 300 mg was not stronger than zolpidem + caffeine 150 mg in impairing immediate memory and causing subjective sedation. In study II, zolpidem caused objective and subjective sedation; neither caffeine nor erythromycin modulated the effects of zolpidem or plasma zolpidem concentrations. The sedative effects of 10 mg of zolpidem are not antagonized by 150-300 mg of caffeine in pharmacodynamic or pharmacokinetic terms.

  5. Effect of reaction time and (Ca+Mg)/Al molar ratios on crystallinity of Ca-Mg-Al layered double Hydroxide

    Heraldy, E.; Nugrahaningtyas, K. D.; Sanjaya, F. B.; Darojat, A. A.; Handayani, D. S.; Hidayat, Y.


    Ca-Mg-Al Layered Double Hydroxides (Ca-Mg-Al-LDH) compounds were successfully synthesized from brine water and AlCl3.6H2O as the starting materials by coprecipitation method. The product result was characterized by X-ray powder diffraction (XRD) and Fourier transform infrared (FT-IR). The effects of the reaction time and the molar ratios of the raw material on the crystallinity of Ca-Mg-Al-LDH were examining. Results show that increasing reaction time (30; 60 and 90 min.) could improve the crystallinity and monodispersity of layered double hydroxide compounds particles. The well-defined Ca-Mg- Al-LDH could be prepared with (Ca+Mg)/Al molar ratios 0.5.

  6. Effect of CaO composition on oxidation and burning behaviors of AM50 Mg alloy

    Jin-Kyu LEE; Shae K. KIM


    Oxidation and burning behaviors were studied for CaO added AM50 Mg composites which were manufactured by conventional melting and casting processes without SF6 protective gas. CaO added AM50 Mg composites show the stable oxidation resistance. while AM50 Mg alloys show the poor oxidation resistance. The effects of CaO addition on the burning resistance under ambient, nitrogen and dry air atmospheres were examined for CaO added AM50 Mg composites. With increasing CaO addition, the burning temperature increases under ambient, nitrogen and dry air atmospheres. The burning temperatures of small test specimen under all conditions greatly increase even by 0.3% CaO (mass fraction) addition into AM50 Mg alloys.

  7. Recovery of SO2 and MgO from By-Products of MgO Wet Flue Gas Desulfurization.

    Yan, Liyun; Lu, Xiaofeng; Wang, Quanhai; Guo, Qiang


    An industrial demonstration unit using natural gas as a heat source was built to calcine the by-products of MgO wet flue gas desulfurization from power plants; influencing factors on the SO2 content in calciner gas were comprehensively analyzed; and an advantageous recycling condition of MgO and SO2 from by-products was summarized. Results showed that the SO2 content in the calciner gas was increased by more than 10 times under a lower excess air coefficient, a higher feed rate, a lower crystal water in by-products, and a higher feed port position. For the tests conducted under the excess air coefficient above and below one, the effect of the furnace temperature on the SO2 content in the calciner gas was reversed. Results of activity analysis indicate that particles of MgO generated under the calcination temperature of 900-1,000°C had a high activity. In contrast, due to the slight sintering, MgO generated under the calcination temperature of 1,100°C had a low activity. To recycle SO2 as well as MgO, a temperature range of 900-927°C for TE103 is proposed. These studies will prompt the desulfurization market diversification, reduce the sulfur's dependence on imports for making sulfuric acid, be meaningful to balance the usage of the natural resource in China, and be regarded as a reference for the development of this technology for other similar developing countries.

  8. Forging of Mg-alloys AZ31 and AZ80

    Viehweger, B.; Karabet, A.; Duering, M. [Brandenburg University of Technology, Interdisciplinary Research Centre for Lightweight Materials ' ' Panta Rhei' ' , Konrad-Wachsmann-Allee 17, 03046 Cottbus (Germany); Schaeffer, L. [Universidade Federal do Rio Grande do Sul, Porto Alegre (Brazil)


    Mg-wrought alloys recently became an engineer material of constantly increasing interest. The mechanical properties of extruded Mg-feedstock of the alloys AZ80 and AZ31 indicate their suitability for automotive applications in form of high-quality forgings. Therefore a detailed knowledge about the forming behaviour is of particular importance. In order to compare mechanical properties of available Mg-feedstock qualities compression tests at room temperature have been carried out by applying batches of AZ31- and AZ80-feedstock. Cylindrical specimens were made out of received continuously casted as well as extruded AZ31- and AZ80 - rods. A quantitative analysis of Mg-feedstock's microstructure has been carried out. The characterization of the deformability of applied Mg-feedstock under hot working conditions could be performed by means of uniaxial plain strain upsetting tests at temperatures between 300 and 450 C as well as logarithmic strain rates of 10{sup -1}, 1 and 10s{sup -1}. It is shown that the chosen parameter range ensures an enhanced deformability of continuously as well as extruded Mg-feedstock. The subsequently carried out determination of microstructural evolution could be related to obtained flow stress curves of applied batches of Mg-feedstock. Furthermore, FVM/FEM-systems have been employed in order to design a simplified geometry of heated forging dies suitable for forging tests. The tests have been carried out by means of a hydraulic press. During the tests their punch velocity has been varied between 1 and 40 mm/s. Hence numerically simulated results could be confirmed by practical tests. Exemplary forgings of a simplified shape were made out of all applied batches of Mg-feedstock. No remarkable failures have been detected. (Abstract Copyright [2005], Wiley Periodicals, Inc.) [German] Das Interesse an Mg-Knetlegierungen als Konstruktionswerkstoff fuer automobile Anwendung ist in juengster Zeit stark gewachsen. Daher ist eine detaillierte

  9. Electronic structure of ferromagnet-insulator interfaces: Fe/MgO and Co/MgO

    Mueller, M.


    In this thesis the electronic structure of Fe/MgO{sub x} and Co/MgO{sub x} ferromagnet-insulator interfaces, representing material systems which are widely used in magnetic tunnel junctions, is studied by means of spin- and angle-resolved photoemission spectroscopy. The photoemission studies focus particularly on the response of the ferromagnetic electronic system in contact with MgO of varying stoichiometries, as this reflects the mechanisms of metal-oxide bonding at real ferromagnet-insulator interfaces. The correlation between chemical bonding and electronic structure formation is analyzed by combining information from core- and valence-band photoemission spectroscopy. The spectral features are compared to band structure calculations, which are performed using the SPR-KKR method. The Fe/MgO and Co/MgO systems are prepared by molecular beam epitaxy under ultrahigh vacuum conditions on well-defined (4 x 6) GaAs(001) substrates. A structural analysis by means of low-energy electron diffraction (LEED) reveals their body-centered cubic crystalline structure, whereas the chemical characterization by Auger electron spectroscopy is used to quantify the chemical environment at the sample surfaces. The magnetic analysis, using the magneto-optical Kerr effect, reveals the uniaxial anisotropy of the ferromagnetic layers. A crucial parameter is given by the MgO degree of oxidation, which is addressed by means of core-level spectroscopy and quantified by suitable fitting procedures of the Mg 2p core level. The results of the photoemission experiments show, that the electronic structure of the Fe/MgO and Co/MgO ferromagnet/insulator interfaces and, consequently, the interfacial spin polarization are sensitively controlled by the interface chemistry. In particular, three distinct scenarios are identified: the nearly stoichiometric, the oxygen-deficient and the over-oxidized ferromagnet/MgO interface. Each case is defined by innate characteristics of the electronic structure at

  10. FeII/MgII, [Fe/Mg] Ratios and High-z Quasars

    Korista, K; Corbin, M R; Freudling, W; Korista, Kirk; Kodituwakku, Nalaka; Corbin, Michael; Freudling, Wolfram


    It has been suggested in the literature that the (Fe/alpha) abundance ratio may be used as a chronometer, due to a delay in this ratio reaching its solar value as predicted by galactic chemical evolution models. Using grids of photoionization models along a sequence of the (Fe/Mg) abundance ratio vs.\\ metallicity with time in a giant elliptical starburst scenario, we investigate the relationship between the (Fe/Mg) abundance ratio and the FeII/MgII emission line flux ratio under the assumption that these lines originate in photoionized clouds within the broad emission line regions of quasars.

  11. Safety and tolerability of donepezil 23 mg in moderate to severe Alzheimer's disease

    Zou Heng


    Full Text Available Abstract Background Donepezil 23 mg/d, recently approved in the United States for treatment of moderate to severe Alzheimer's disease (AD, was developed to address the need for an additional treatment option for patients with advanced AD. This report, based on a pivotal phase 3 study, presents a detailed analysis of the safety and tolerability of increasing donepezil to 23 mg/d compared with continuing 10 mg/d. Method Safety analyses comprised examination of the incidence, severity, and timing of treatment-emergent adverse events (AEs and their relationship to treatment initiation; changes in weight, electrocardiogram, vital signs, and laboratory parameters; and the incidence of premature study discontinuation. The analysis population (n = 1434 included all randomized patients who took at least 1 dose of study drug and had a postbaseline safety assessment. To further examine the effect of transition from a lower to a higher donepezil dose, a pooled analysis of safety data from 2 phase 3 trials of donepezil 5 mg/d and 10 mg/d was also performed. Results The safety population comprised 1434 patients: donepezil 23 mg/d (n = 963; donepezil 10 mg/d (n = 471; completion rates were 71.1% and 84.7%, respectively. The most common AEs were nausea, vomiting, and diarrhea (donepezil 23 mg/d: 11.8%, 9.2%, 8.3%; donepezil 10 mg/d: 3.4%, 2.5%, 5.3%, respectively. AEs that contributed most to early discontinuations were vomiting (2.9% of patients in the 23 mg/d group and 0.4% in the 10 mg/d group, nausea (1.9% and 0.4%, diarrhea (1.7% and 0.4%, and dizziness (1.1% and 0.0%. The percentages of patients with AEs in the 23 mg/d group, as well as the timing, type, and severity of these AEs, were similar to those seen in previous donepezil trials with titration from 5 to 10 mg/d. Serious AEs were uncommon (23 mg/d, 8.3%; 10 mg/d, 9.6%. Discussion The 23 mg/d dose of donepezil was associated with typical cholinergic AEs, particularly gastrointestinal-related AEs

  12. Interplay of Mg2+, ADP, and ATP in the cytosol and mitochondria: unravelling the role of Mg2+ in cell respiration.

    Gout, Elisabeth; Rébeillé, Fabrice; Douce, Roland; Bligny, Richard


    In animal and plant cells, the ATP/ADP ratio and/or energy charge are generally considered key parameters regulating metabolism and respiration. The major alternative issue of whether the cytosolic and mitochondrial concentrations of ADP and ATP directly mediate cell respiration remains unclear, however. In addition, because only free nucleotides are exchanged by the mitochondrial ADP/ATP carrier, whereas MgADP is the substrate of ATP synthase (EC, the cytosolic and mitochondrial Mg(2+) concentrations must be considered as well. Here we developed in vivo/in vitro techniques using (31)P-NMR spectroscopy to simultaneously measure these key components in subcellular compartments. We show that heterotrophic sycamore (Acer pseudoplatanus L.) cells incubated in various nutrient media contain low, stable cytosolic ADP and Mg(2+) concentrations, unlike ATP. ADP is mainly free in the cytosol, but complexed by Mg(2+) in the mitochondrial matrix, where [Mg(2+)] is tenfold higher. In contrast, owing to a much higher affinity for Mg(2+), ATP is mostly complexed by Mg(2+) in both compartments. Mg(2+) starvation used to alter cytosolic and mitochondrial [Mg(2+)] reversibly increases free nucleotide concentration in the cytosol and matrix, enhances ADP at the expense of ATP, decreases coupled respiration, and stops cell growth. We conclude that the cytosolic ADP concentration, and not ATP, ATP/ADP ratio, or energy charge, controls the respiration of plant cells. The Mg(2+) concentration, remarkably constant and low in the cytosol and tenfold higher in the matrix, mediates ADP/ATP exchange between the cytosol and matrix, [MgADP]-dependent mitochondrial ATP synthase activity, and cytosolic free ADP homeostasis.

  13. Hg Substitution Effect on Superconductivity and Crystal Structure of MgB2

    Ya-Jing Cui; Yong-Liang Chen; Ye Yang; Yong Zhang; Cui-Hua Cheng; Yong Zhao


    Polycrystalline Mg1-xHgxB2 samples with x=0, 1%, 2.5%, 5%, 7.5%, and 10% have been synthe- sized by solid-state reaction. Different from the substitu- tion effect of Al, C, Li, etc. on crystal structure of MgB2, Hg substitution for Mg results in an increase of the lattice constant in both a and c directions. The super- conductivity of MgB2 is also suppressed by Hg substi- tution. The observed suppression of super- conductivity by Hg substitution is discussed in terms of the interband impurity scattering effect in two-band superconductors.

  14. Modern and Cenozoic records of seawater magnesium from foraminiferal Mg isotopes

    Pogge von Strandmann, P. A. E.; Forshaw, J.; Schmidt, D. N.


    Magnesium is an element critically involved in the carbon cycle, because weathering of Ca-Mg silicates removes atmospheric CO2 into rivers, and formation of Ca-Mg carbonates in the oceans removes carbon from the ocean-atmosphere system. Hence the Mg cycle holds the potential to provide valuable insights into Cenozoic climate-system history, and the shift during this time from a greenhouse to icehouse state. We present Mg isotope ratios for the past 40 Myr using planktic foraminifers as an archive. Modern foraminifera, which discriminate against elemental and isotopically heavy Mg during calcification, show no correlation between the Mg isotope composition (δ26Mg, relative to DSM-3) and temperature, Mg / Ca or other parameters such as carbonate saturation (ΔCO3). However, inter-species isotopic differences imply that only well-calibrated single species should be used for reconstruction of past seawater. Seawater δ26Mg inferred from the foraminiferal record decreased from ~0‰ at 15 Ma, to -0.83‰ at the present day, which coincides with increases in seawater lithium and oxygen isotope ratios. It strongly suggests that neither Mg concentrations nor isotope ratios are at steady state in modern oceans, given its ~10 Myr residence time. From these data, we have developed a dynamic box model to understand and constrain changes in Mg sources to the oceans (rivers) and Mg sinks (dolomitisation and hydrothermal alteration). Our estimates of seawater Mg concentrations through time are similar to those independently determined by pore waters and fluid inclusions. Modelling suggests that dolomite formation and the riverine Mg flux are the primary controls on the δ26Mg of seawater, while hydrothermal Mg removal and the δ26Mg of rivers are more minor controls. Using Mg riverine flux and isotope ratios inferred from the 87Sr / 86Sr record, the modelled Mg removal by dolomite formation shows minima in the Oligocene and at the present day (with decreasing trends from 15 Ma

  15. A first-principles study of the thermodynamic and electronic properties of Mg and MgH2 nanowires.

    Wu, Xinxing; Zhang, Ruiqi; Yang, Jinlong


    In this article, we studied the thermodynamic and electronic properties of Mg and MgH2 nanowires with different diameters, and elucidated why MgH2 nanowires are good hydrogen storage materials through first-principles calculations. Previous experiments have shown that the orientation relationship between Mg and MgH2 nanowires is the Mg[0001] direction parallel to the MgH2[110] direction. In our calculations, Mg nanowires oriented along the [0001] direction and MgH2 nanowires oriented along the [110] direction were built from bulk Mg and MgH2 crystals, respectively. We found that as the diameters of Mg and MgH2 nanowires decrease, Mg and MgH2 nanowires become more unstable, and the hydrogen desorption energies and temperatures of MgH2 nanowires decrease. That is, the thinner the MgH2 nanowires get, the more dramatically hydrogen desorption temperatures (Td) will decrease. Meanwhile, we also found that when the diameters of MgH2 nanowires are larger than 1.94 nm, the Td almost maintain the same value at about 440 K, only about 40 K lower than that of bulk MgH2 crystal; if the diameters are less than 1.94 nm, the Td reduce very quickly. In particular, compared with bulk MgH2 crystal, the Td of the thinnest MgH2 nanowire with a diameter of 0.63 nm can be reduced by 164 K. In addition, the electronic structure calculations showed that Mg nanowires are metals, while MgH2 nanowires are semiconductors. In particular, our results showed that the electronic structures of MgH2 nanowires are influenced by the surface effect and quantum size effect. That is to say, the band gaps of MgH2 nanowires are controlled by surface electronic states and the size of MgH2 nanowires.

  16. Yohimbine increases human salivary secretion.

    Chatelut, E; Rispail, Y; Berlan, M; Montastruc, J L


    The effect of oral yohimbine (14 mg) on salivary secretion was evaluated in healthy volunteers. Yohimbine significantly increased salivary secretion when compared with placebo. This effect was significant from 60 min until 180 min after administration under our experimental conditions. Yohimbine (or alpha 2-adrenoceptor blocking agents) could have a potential interest in the treatment of dry mouths. PMID:2789932

  17. Proteome of Salmonella enterica serotype Tyhimurium Grown in Low Mg2+/pH Medium

    Shi, Liang; Ansong, Charles; Smallwood, Heather S.; Rommereim, Leah M.; McDermott, Jason E.; Brewer, Heather M.; Norbeck, Angela D.; Taylor, Ronald C.; Gustin, Jean K.; Heffron, Fred; Smith, Richard D.; Adkins, Joshua N.


    To determine the impact of a low Mg2+/pH defined growth medium (MgM) on the proteome of Salmonella enterica serotype Typhimurium, we cultured S. Typhimurium cells in the medium under two different conditions termed MgM Shock and MgM Dilution and then comparatively analyzed the bacterial cells harvested from these conditions by a global proteomic approach. Proteomic results showed that MgM Shock and MgM Dilution differentially affected the S. Typhimurium proteome. MgM Shock induced a group of proteins whose induction usually occurred at low O2 level, while MgM Dilution induced those related to the type III secretion system (T3SS) of Salmonella Pathogenicity Island 2 (SPI2) and those involved in thiamine or biotin biosynthesis. The metabolic state of the S. Typhimurium cells grown under MgM Shock condition also differed significantly from that under MgM Dilution condition. Western blot analysis not only confirmed the proteomic results, but also showed that the abundances of SPI2-T3SS proteins SsaQ and SseE and biotin biosynthesis proteins BioB and BioD increased after S. Typhimurium infection of RAW 264.7 macrophages. Deletion of the gene encoding BioB reduced the bacterial ability to replicate inside the macrophages, suggesting a biotin-limited environment encountered by S. Typhimurium within RAW 264.7 macrophages.

  18. Effective nanoconfinement of 2LiBH4-MgH2 via simply MgH2 premilling for reversible hydrogen storages

    Utke, Rapee Gosalawit; Thiangviriya, Sophida; Javadian, Payam


    MgH2. Significant confinement of both LiBH4 and MgH2 in CAS, confirmed by SEM-EDS mapping results, is achieved due to MgH2 premilling. Due to effective nanoconfinement, enhancement of CAS:hydride composite weight ratio to 1:1, resulting in increase of hydrogen storage capacity, is possible...... are accomplished after MgH2 premilling. Three hydrogen release (T = 320 degrees C, P(H-2) = 3-4 bar) and uptake (T = 320-325 degrees C, P(H-2) = 84 bar) cycles of nanoconfined 2LiBH(4)-premilled MgH2 reveal up to 4.96 wt. % H-2 (10 Wt. % H-2 with respect to hydride composite content), while the 1st desorption......To improve nanoconfinement of LiBH4 and MgH2 in carbon aerogel scaffold (CAS), particle size reduction of MgH2 by premilling technique before melt infiltration is proposed. MgH2 is premilled for 5 h prior to milling with LiBH4 and nanoconfinement in CAS to obtained nanoconfined 2LiBH(4)-premilled...

  19. Microstructure and superconducting properties of nanocarbon-doped internal Mg diffusion-processed MgB2 wires fabricated using different boron powders

    Xu, Da; Wang, Dongliang; Li, Chen; Yuan, Pusheng; Zhang, Xianping; Yao, Chao; Dong, Chiheng; Huang, He; Ma, Yanwei; Oguro, Hidetoshi; Awaji, Satoshi; Watanabe, Kazuo


    MgB2/Nb/Monel monofilament wires were fabricated using four different boron powders by an internal Mg diffusion (IMD) process. The microstructure, morphology and the critical current density (J c) of the used boron powders and the formative MgB2 layers were analyzed and compared. It was found that the purity and particle size of the boron powder influence the superconducting properties of MgB2 wires; further that the optimized heat-treatment condition also depends on the quality of the boron powder. The highest J c was obtained in the MgB2 layer made using amorphous boron (AB) powder, although a certain amount of voids existed in the superconducting layer. The IMD-processed MgB2 layer fabricated using high-purity boron (HB) powder had also a high J c compared with the powder-in-tube (PIT) process and a few unreacted boron particles remained in it. MgB2 wire fabricated using low-purity boron (LB) powder had a high cost-performance ratio compared with the others, which is expected to allow the fabrication of large-scale and low-cost superconducting wires for practical application. However, the enhancement of the J c was not found in the MgB2 layer manufactured using the ball-milled LB (MLB) powder as expected due to the increased percentage of impurity.

  20. Efficacy and tolerability of rizatriptan 10 mg compared with sumatriptan 100 mg: an evidence-based analysis.

    Göbel, Hartmut


    Acute migraine attacks have a strong impact on quality of life and require immediate therapeutic intervention to achieve rapid pain relief. The introduction of triptans into the market in 1993 has increased the therapeutic options in migraine patients considerably. The seven currently available triptans show many similar characteristics but there are also some clinically relevant pharmacological differences. Rizatriptan 10 mg has demonstrated, in a head-to-head study, higher response rates and a more rapid onset of action than sumatriptan 100 mg, together with a favorable tolerability profile. Meta-analyses of double-blind placebo-controlled studies confirmed the superior efficacy of rizatriptan. Owing to the limited efficacy of sumatriptan, a more effective triptan treatment is needed in the majority of patients with acute migraine attacks.

  1. Microstructural evolution of Mg-7Al-2Sn Mg alloy during multi-directional impact forging

    M.G. Jiang


    Full Text Available Multi-directional impact forging (MDIF was applied to a Mg-7Al-2Sn (wt.% Mg alloy to investigate its effect on the microstructural evolution. MDIF process exhibited high grain refinement efficiency. After MDIF 200 passes, the grain size drastically decreased to 20 µm from the initial coarse grains of ~500 µm due to dynamic recrystallization (DRX. Meanwhile, original grain boundaries remained during MDIF and large numbers of fine spherical β-Mg17Al12 particles dynamically precipitated along the original grain boundaries with high Al concentration, acting as effective pinning obstacles for the suppression of DRXed grain growth. Besides, micro-cracks nucleated during MDIF and propagated along the interface between the remained globular or cubic Al-Mn particles and Mg matrix.

  2. Proton resonance elastic scattering of $^{30}$Mg for single particle structure of $^{31}$Mg

    The single particle structure of $^{31}$Mg, which is located in the so-called “island of inversion”, will be studied through measuring Isobaric Analog Resonances (IARs) of bound states of $^{31}$Mg. They are located in the high excitation energy of $^{31}$Al. We are going to determine the spectroscopic factors and angular momenta of the parent states by measuring the excitation function of the proton resonance elastic scattering around 0 degrees in the laboratory frame with around 3 MeV/nucleon $^{30}$Mg beam. The present study will reveal the shell evolution around $^{32}$Mg. In addition, the spectroscopic factor of the (7/2)$^{−}$ state which was not yet determined experimentally, may allow one to study the shape coexistence in this nucleus.

  3. Evolution of Mg-5Al-0.4Mn microstructure after rare earth elements addition

    A. Żydek


    Full Text Available Mg-5Al-0.4Mn-xRE (x = 0, 1, 2, 3 wt.% magnesium alloys were prepared successfully by casting method. The microstructure wasinvestigated by light microscopy. The influence of rare earth (RE elements on the area fraction of eutectic was analysed. The obtainedresults revealed that the as-cast Mg-5Al-0.4Mn alloy consist of α - Mg matrix and eutectic α + γ (where γ is Mg17Al12. However, whilerare earth elements were added to the Mg-Al type alloy, Al11RE3 precipitates were formed. The amount of the Al11RE3 precipitatesincreased with increasing addition of RE, but the amount of γ - Mg17Al12 decreased.

  4. Assessment of pulmonary toxicity of MgO nanoparticles in rats.

    Gelli, Kiranmai; Porika, Mahendar; Anreddy, Rama Narsimha Reddy


    In this study, we have evaluated the pulmonary toxicity of MgO nanoparticles (MgO NPs) in rats following their exposure. NPs in phosphate buffered saline + 1% Tween 80 were exposed via intratracheal instillation at a doses of 1 mg/kg or 5 mg/kg into rat lungs and evaluated for various tissue damage markers like alkaline phosphatase (ALP) and lactate dehydrogenase (LDH) in bronchoalveolar lavage (BAL) fluid and histopathology of lungs at 1, 7, and 30 days of post-exposure intervals. A dose-dependant increase in ALP and LDH activity was observed in BAL fluids of rat lungs than sham control at all post-exposure periods (P MgO NPs. In conclusion, MgO NPs exposure produced a dose-dependent pulmonary toxicity in rats and was comparable with that of Quartz particles.

  5. Promising gaseous and electrochemical hydrogen storage properties of porous Mg-Pd films under mild conditions.

    Xin, Gongbiao; Yuan, Huiping; Jiang, Lijun; Wang, Shumao; Liu, Xiaopeng; Li, Xingguo


    In this paper, the gaseous and electrochemical hydrogen storage properties of 200 nm Mg-Pd thin films with different morphologies have been investigated. The results show that Mg-Pd films become porous with the increase of substrate temperature. Porous Mg-Pd films exhibit superior gaseous and electrochemical hydrogen storage behaviors under mild conditions, including rapid hydrogen sorption kinetics, a large hydrogen storage amount, high electrochemical discharge capacity, and a fast hydrogen diffusion rate. The excellent behaviors of porous Mg-Pd films might be ascribed to the significantly shortened hydrogen diffusion paths and the large contact areas between the hydrogen gas and the solid Mg phases, which are elucidative for the development and applications of thick Mg-Pd films.

  6. Effective modification of MgO with surface transition metal oxides for NF3 decomposition

    Yanan Wang; Xiufeng Xu; Pei Sheng; Hongguang Li; Tingting Wang; Youfen Huang; Fangshu Liu


    NF3 decomposition over transition metal oxides coated MgO reagents in the absence of water is investigated.The results show that NF3 can be decomposed completely over pure MgO but the time of NF3 steady full conversion kept as short as 80 min,while the reactivities of coated MgO reagents were remarkably enhanced by transition metal oxides,for example the time of NF3 complete conversion over 12%Fe/MgO extended to 380 min.It is suggested that not only an increase in surface area but also a significant enhancement in the fluorination of MgO substrate caused by the surface transition metal oxides result in an improved reactivity of coated MgO reagents for NF3 decomposition.

  7. Microstructure and Raman spectra of Ag-MgF2 cermet films

    Shouhua Shi(史守华); Zhuoliang Cao(曹卓良); Zhaoqi Sun(孙兆奇)


    Ag-MgF2 cermet films with different Ag fractions were prepared by vacuum evaporation. The microstruc-ture of the films was examined by Raman scattering technique. The surface-enhanced Raman spectrumfor MgF2 molecules in the cermet film strongly suggests the existence of Ag nanoparticles dispersed inMgF2 matrix. The intensities of the Raman spectra of Ag-MgF2 cermet films increase with Ag fraction.The enhancement of Raman scattering disappears when Ag content reaches wt.20%. The analyses withthe transmission electron microscopy showed that Ag-MgF2 cermet films are mainly composed of amor-phous MgF2 matrix with embedded faced-center-cubic Ag nanoparticles. It suggests that the percolationthreshold should be around wt.20% of Ag content.

  8. Thermodynamic Property Study of Nanostructured Mg-H, Mg-Ni-H, and Mg-Cu-H Systems by High Pressure DSC Method

    Huaiyu Shao


    Full Text Available Mg, Ni, and Cu nanoparticles were synthesized by hydrogen plasma metal reaction method. Preparation of Mg2Ni and Mg2Cu alloys from these Mg, Ni, and Cu nanoparticles has been successfully achieved in convenient conditions. High pressure differential scanning calorimetry (DSC technique in hydrogen atmosphere was applied to study the synthesis and thermodynamic properties of the hydrogen absorption/desorption processes of nanostructured Mg-H, Mg-Ni-H, and Mg-Cu-H systems. Van’t Hoff equation of Mg-Ni-H system as well as formation enthalpy and entropy of Mg2NiH4 was obtained by high pressure DSC method. The results agree with the ones by pressure-composition isotherm (PCT methods in our previous work and the ones in literature.

  9. Magnesium homeostasis in cardiac myocytes of Mg-deficient rats.

    Michiko Tashiro

    Full Text Available To study possible modulation of Mg(2+ transport in low Mg(2+ conditions, we fed either a Mg-deficient diet or a Mg-containing diet (control to Wistar rats for 1-6 weeks. Total Mg concentrations in serum and cardiac ventricular tissues were measured by atomic absorption spectroscopy. Intracellular free Mg(2+ concentration ([Mg(2+]i of ventricular myocytes was measured with the fluorescent indicator furaptra. Mg(2+ transport rates, rates of Mg(2+ influx and Mg(2+ efflux, were estimated from the rates of change in [Mg(2+]i during Mg loading/depletion and recovery procedures. In Mg-deficient rats, the serum total Mg concentration (0.29±0.026 mM was significantly lower than in control rats (0.86±0.072 mM after 4-6 weeks of Mg deficiency. However, neither total Mg concentration in ventricular tissues nor [Mg(2+]i of ventricular myocytes was significantly different between Mg-deficient rats and control rats. The rates of Mg(2+ influx and efflux were not significantly different in both groups. In addition, quantitative RT-PCR revealed that Mg deficiency did not substantially change mRNA expression levels of known Mg(2+ channels/transporters (TRPM6, TRPM7, MagT1, SLC41A1 and ACDP2 in heart and kidney tissues. These results suggest that [Mg(2+]i as well as the total Mg content of cardiac myocytes, was well maintained even under chronic hypomagnesemia without persistent modulation in function and expression of major Mg(2+ channels/transporters in the heart.

  10. Antibacterial activities of magnesium oxide (MgO) nanoparticles against foodborne pathogens

    Jin, Tony; He, Yiping


    The antibacterial activities of magnesium oxide nanoparticles (MgO NP) alone or in combination with other antimicrobials (nisin and ZnO NP) against Escherichia coli O157:H7 and Salmonella Stanley were investigated. The results show that MgO NP have strong bactericidal activity against the pathogens, achieving more than 7 log reductions in bacterial counts. The antibacterial activity of MgO NP increased as the concentrations of MgO increased. A synergistic effect of MgO in combination with nisin was observed as well. However, the addition of ZnO NP to MgO NP did not enhance the antibacterial activity of MgO against both pathogens. Scanning electron microscopy was used to characterize the morphological changes of E. coli O157:H7 before and after antimicrobial treatments. It was revealed that MgO NP treatments distort and damage the cell membrane, resulting in a leakage of intracellular contents and eventually the death of bacterial cells. These results suggest that MgO NP alone or in combination with nisin could potentially be used as an effective antibacterial agent to enhance food safety.

  11. Caffeine ingestion after rapid weight loss in judo athletes reduces perceived effort and increases plasma lactate concentration without improving performance.

    Lopes-Silva, Joao P; Felippe, Leandro J C; Silva-Cavalcante, Marcos D; Bertuzzi, Romulo; Lima-Silva, Adriano E


    The objective of this study was to examine the effect of caffeine on judo performance, perceived exertion, and plasma lactate response when ingested during recovery from a 5-day weight loss period. Six judokas performed two cycles of a 5-day rapid weight loss procedure to reduce their body weight by ~5%. After weigh-in, subjects re-fed and rehydrated over a 4-h recovery period. In the third hour of this "loading period", subjects ingested a capsule containing either caffeine (6 mg·kg-1) or placebo. One hour later, participants performed three bouts of a judo fitness test with 5-min recovery periods. Perceived exertion and plasma lactate were measured before and immediately after each test bout. Body weight was reduced in both caffeine and placebo conditions after the weight loss period (-3.9% ± 1.6% and -4.0% ± 2.3% from control, respectively, p caffeine or placebo groups. However, plasma lactate was systemically higher and perceived exertion lower in the subjects who ingested caffeine compared to either the control or placebo subjects (p caffeine did not improve performance during the judo fitness test after a 5-day weight loss period, but reduced perceived exertion and increased plasma lactate.

  12. Porous Ceramic Composite ZrO2(MgO)-MgO for Osteoimplantology

    Buyakov, A. S.; Kulkov, S. N.


    Pore and crystalline structure, biocompatibility of ceramic composite ZrO2(MgO)-MgO were studied. The main mechanical characteristics were determined and it has been shown that compression strength directly depends on microstresses obtained from X-ray data. In-vitro studies of mesenchymal stromal stem cells (MMSC), cultivated on material surface are shown that cell proliferation and differentiation of MMSC goes throw osteogenic type.

  13. Flunarizine in migraine prophylaxis: efficacy and tolerability of 5 mg and 10 mg dose levels.

    Centonze, V; Magrone, D; Vino, M; Caporaletti, P; Attolini, E; Campanale, G; Albano, O


    The use of flunarizine, a drug which has proven its efficacy in migraine, is often associated with important side effects. The aim of this paper has been to check their incidence at different dose levels (5 mg vs 10 mg). Our data confirm the occurrence of important side effects (in particular weight gain); on the other hand, they emphasize the dose-dependency of the side effects.

  14. Enhanced mechanical properties of an Al–Si–Cu–Mg alloy at 300 °C: Effects of Mg and the Q-precipitate phase

    Farkoosh, A.R., E-mail:; Pekguleryuz, M., E-mail:


    Strategies to improve the strength of Al–Si alloys at elevated temperatures can follow two routes: (i) improving the age-hardening behavior and/or (ii) producing effective dispersoid strengthening. In this study, the influence of Mg (in the range of 0.3–0.7 wt%) on the precipitation characteristics and mechanical properties of the Al–7Si–0.5Cu–(Mg) alloy was investigated. Thermodynamic calculations were performed via the CALPHAD method which showed that Q-Al{sub 5}Mg{sub 8}Cu{sub 2}Si{sub 6} is the main thermodynamically stable precipitate at 300 °C. The calculations were validated by transmission electron microscopy and differential scanning calorimetry analyses. Increasing the Mg level from 0.3 wt% to the maximum solubility limit of ∼0.5 wt% increased the amount of the Q-Al{sub 5}Mg{sub 8}Cu{sub 2}Si{sub 6} precipitates at 300 °C by ∼60 wt% and significantly improved the tensile strength and creep resistance at the expense of some ductility. Mg in excess of the solubility limit was seen to remain within the microstructure in the form of the large π-Al{sub 8}FeMg{sub 3}Si{sub 6} and β-Mg{sub 2}Si intermetallics after solution treatment at 530 °C. Cracking of the brittle π-Al{sub 8}FeMg{sub 3}Si{sub 6} intermetallics during deformation was accounted for the decreased ductility of the alloys at high Mg levels. It is concluded that the Mg level can be increased to 0.5 wt% in the A–7Si–0.5Cu alloys to improve strength. However, for elevated temperature applications in which both strength and ductility are required (e.g. Diesel engine), modification of the π-Al{sub 8}FeMg{sub 3}Si{sub 6} intermetallics would be required to improve the ductility of the alloys with high Mg contents.

  15. Laser cooling of MgCl and MgBr in theoretical approach

    Wan, Mingjie; Shao, Juxiang; Huang, Duohui; Yang, Junsheng; Cao, Qilong; Jin, Chengguo; Wang, Fanhou, E-mail: [Computational Physics Key Laboratory of Sichuan Province, Yibin University, Yibin 644007 (China); Gao, Yufeng [Institute of Atomic and Molecular Physics, Sichuan University, Chengdu 610065 (China)


    Ab initio calculations for three low-lying electronic states (X{sup 2}Σ{sup +}, A{sup 2}Π, and 2{sup 2}Π) of MgCl and MgBr molecules, including spin-orbit coupling, are performed using multi-reference configuration interaction plus Davidson correction method. The calculations involve all-electronic basis sets and Douglas–Kroll scalar relativistic correction. Spectroscopic parameters well agree with available theoretical and experimental data. Highly diagonally distributed Franck-Condon factors f{sub 00} for A{sup 2}Π{sub 3/2,1/2} (υ′ = 0) → X{sup 2}Σ{sup +}{sub 1/2} (υ″ = 0) are determined for both MgCl and MgBr molecules. Suitable radiative lifetimes τ of A{sup 2}Π{sub 3/2,1/2} (υ′ = 0) states for rapid laser cooling are also obtained. The proposed laser drives A{sup 2}Π{sub 3/2} (υ′ = 0) → X{sup 2}Σ{sup +}{sub 1/2} (υ″ = 0) transition by using three wavelengths (main pump laser λ{sub 00}; two repumping lasers λ{sub 10} and λ{sub 21}). These results indicate the probability of laser cooling MgCl and MgBr molecules.

  16. Fabrication of all-MgB Josephson junctions using MgO insulator layer

    Oba, T. [Graduate School of Engineering, Iwate University, 4-3-5, Ueda, Morioka 020-8551 (Japan); Goto, S. [Lightom, 95-2 Sugo, Takizawa 020-0173 (Japan); Sasaki, S.; Nakanishi, Y.; Fujino, T. [Graduate School of Engineering, Iwate University, 4-3-5, Ueda, Morioka 020-8551 (Japan); Harada, Y. [JST Satellite Iwate, Japan Science and Technology Agency, 3-35-2 Iiokashinden, Morioka, Iwate 020-0852 (Japan); Nakamura, M. [Graduate School of Engineering, Iwate University, 4-3-5, Ueda, Morioka 020-8551 (Japan); Saito, A. [Department of Electrical Engineering, Yamagata University, 4-3-16, Jonan, Yonezawa, Yamagata 992-8510 (Japan); Yoshizawa, M. [Graduate School of Engineering, Iwate University, 4-3-5, Ueda, Morioka 020-8551 (Japan)], E-mail:


    We report on the fabrication and properties of all-MgB{sub 2} tunnel junctions with an MgO barrier. Superconductor-insulator-superconductor (SIS) junctions were fabricated on C-plane sapphire substrates. MgB{sub 2} films were grown in an ultra-high vacuum in the 10{sup -9} Torr range. The MgO insulating layer was evaporated using an electron-beam gun. SIS junctions of 30 {mu}m in diameter were fabricated by standard photolithography and Ar ion milling techniques. The critical temperature (T{sub C}) of the lower MgB{sub 2} layer after the SIS junction fabrication process was 36.7 K, which remained the same as that of the bare MgB{sub 2} film. We observed tunneling behavior in the current-voltage (I-V) characteristics of the present junctions. A superconducting gap was clearly observed at around 2.7 mV (=2{delta})

  17. Preference for rizatriptan 10-mg wafer vs. eletriptan 40-mg tablet for acute treatment of migraine.

    Láinez, M J A; Evers, S; Kinge, E; Allais, G; Allen, C; Rao, N A; Massaad, R; Lis, K


    Preference is a composite, patient-oriented endpoint incorporating efficacy, tolerability, formulation, and convenience of medications. The objective of this study was to compare patient preference for rizatriptan 10-mg wafer vs. eletriptan 40-mg tablet for acute treatment of migraine. In this multicentre, open-label, two-period, crossover study, out-patients were randomly assigned to treat the first of two moderate to severe migraines with rizatriptan or eletriptan and the second with the alternate therapy. Patients completed diary assessments at baseline and up to 24 h after taking study medication. At the last visit, patients completed a psychometrically validated preference questionnaire. A total of 372 patients (mean age 38 years, 85% female) treated two migraine attacks, and 342 patients (92%) expressed a preference for treatment. Significantly more (P rizatriptan 10-mg wafer [61.1%; 95% confidence interval (CI) 55.7, 66.3] to eletriptan 40-mg tablet (38.9%; 95% CI 33.7, 44.3). The most common reason given for preference of either treatment was speed of headache relief. At 2 h, 80% and 69% of patients reported that rizatriptan and eletriptan, respectively, was convenient or very convenient to take (mean convenience score 1.99 vs. 2.31, respectively; P rizatriptan 10-mg wafer to the eletriptan 40-mg tablet for acute treatment of migraine. The single most important reason for preference was speed of relief, consistent with results from previous preference studies.

  18. Laser cooling of MgCl and MgBr in theoretical approach.

    Wan, Mingjie; Shao, Juxiang; Gao, Yufeng; Huang, Duohui; Yang, Junsheng; Cao, Qilong; Jin, Chengguo; Wang, Fanhou


    Ab initio calculations for three low-lying electronic states (X(2)Σ(+), A(2)Π, and 2(2)Π) of MgCl and MgBr molecules, including spin-orbit coupling, are performed using multi-reference configuration interaction plus Davidson correction method. The calculations involve all-electronic basis sets and Douglas-Kroll scalar relativistic correction. Spectroscopic parameters well agree with available theoretical and experimental data. Highly diagonally distributed Franck-Condon factors f00 for A(2)Π3/2,1/2 (υ' = 0) → X(2)Σ(+) 1/2 (υ″ = 0) are determined for both MgCl and MgBr molecules. Suitable radiative lifetimes τ of A(2)Π3/2,1/2 (υ' = 0) states for rapid laser cooling are also obtained. The proposed laser drives A(2)Π3/2 (υ' = 0) → X(2)Σ(+) 1/2 (υ″ = 0) transition by using three wavelengths (main pump laser λ00; two repumping lasers λ10 and λ21). These results indicate the probability of laser cooling MgCl and MgBr molecules.

  19. Raman scattering study of α-MgH2 and γ-MgH2

    Kuzovnikov, M. A.; Efimchenko, V. S.; Filatov, E. V.; Maksimov, A. A.; Tartakovskii, I. I.; Ramirez-Cuesta, A. J.


    Two modifications of MgH2 have been studied by Raman spectroscopy: α-MgH2 with the P42/mnm space group and γ-MgH2 with the Pbcn space group. The latter was prepared from α-MgH2 by exposing it to a pressure of 5.6 GPa at 470 °C for 1.5 h. A comparison of the experimental spectra with ab-initio calculations allowed identification of a few phonon modes. A broad feature in the Raman spectrum of α-MgH2 in the range 1470-1790 cm-1 was identified as the B2g phonon mode. A Raman spectrum of γ-MgH2 consists of five discernible peaks at 186 cm-1, 313 cm-1, 509 cm-1, 660 cm-1, 706 cm-1 and of three broad features in the regions 890-980 cm-1, 1010-1220 cm-1 and 1240-1430 cm-1. The peaks are identified as the 1Ag (186 cm-1), 3B3g (509 cm-1), 2Ag (660 cm-1) and 3B1g (706 cm-1) phonon modes.

  20. Corrosion characteristics of Al-Si-Mg/SiC{sub p} composites with varying Si/Mg molar ratio in neutral chloride solutions

    Escalera-Lozano, R.; Pech-Canul, M.I. [Cinvestav Saltillo (Mexico); Pech-Canul, M.A.; Quintana, P. [Departamento de Fisica Aplicada, Merida, Yuc. (Mexico)


    The corrosion resistance of Al-Mg-Si/SiC{sub p} composites produced by the pressureless infiltration method [using SiC{sub p} preforms with 50% porosity containing rice hull ash (RHA) and four custom-made alloys with varying Si/Mg molar ratio] was evaluated in neutral 0.1 M NaCl solutions. The deleterious phase Al{sub 4}C{sub 3} was successfully suppressed in composites with Si/Mg molar ratios of 0.89 and 1.05, but not in those with lower Si/Mg molar ratios (0.12 and 0.49). Results of cyclic polarizations in deareated 0.1 M NaCl solutions showed that with increasing Si/Mg molar ratio, passive current density increased but pitting susceptibility decreased both for reinforced and unreinforced alloys. Immersion tests in aerated 0.1 M NaCl showed that for composites with Si/Mg molar ratios of 0.12 and 0.49 chemical degradation by hydrolysis of Al{sub 4}C{sub 3} was followed by intense anodic dissolution at the matrix-reinforcement interface, while composites corresponding to Si/Mg molar ratios of 0.89 and 1.05 did not exhibit intense localized attack. Possible reasons for the improvement in resistance to localized corrosion are discussed. (Abstract Copyright [2009], Wiley Periodicals, Inc.)

  1. Comparison of Efficiencies and Mechanisms of Catalytic Ozonation of Recalcitrant Petroleum Refinery Wastewater by Ce, Mg, and Ce-Mg Oxides Loaded Al2O3

    Chunmao Chen


    Full Text Available The use of catalytic ozonation processes (COPs for the advanced treatment of recalcitrant petroleum refinery wastewater (RPRW is rapidly expanding. In this study, magnesium (Mg, cerium (Ce, and Mg-Ce oxide-loaded alumina (Al2O3 were developed as cost efficient catalysts for ozonation treatment of RPRW, having performance metrics that meet new discharge standards. Interactions between the metal oxides and the Al2O3 support influence the catalytic properties, as well as the efficiency and mechanism. Mg-Ce/Al2O3 (Mg-Ce/Al2O3-COP reduced the chemical oxygen demand by 4.7%, 4.1%, 6.0%, and 17.5% relative to Mg/Al2O3-COP, Ce/Al2O3-COP, Al2O3-COP, and single ozonation, respectively. The loaded composite metal oxides significantly increased the hydroxyl radical-mediated oxidation. Surface hydroxyl groups (–OHs are the dominant catalytic active sites on Al2O3. These active surface –OHs along with the deposited metal oxides (Mg2+ and/or Ce4+ increased the catalytic activity. The Mg-Ce/Al2O3 catalyst can be economically produced, has high efficiency, and is stable under acidic and alkaline conditions.

  2. Dehydrogenation kinetics of air-exposed MgH2/Mg2Cu and MgH2/MgCu2 studied with in situ X-ray powder diffraction

    Andreasen, A.; Sørensen, M.B.; Burkarl, R.


    The dehydrogenation kinetics of air exposed samples of MgH2/Mg2Cu and MgH2/MgCu2 have been studied with in situ time resolved X-ray powder diffraction. The X-ray setup enabled the recording of full diffraction patterns within 150 s, thereby allowing the study of structural changes combined...... sample was found to be 108 kJ/mol and 160 kJ/mol, respectively. Furthermore, substantially improved dehydrogenation kinetics of MgH2 and resistance towards oxidation of Mg due to the presence of Mg2Cu/MgCu2 are discussed in relation to previous work....

  3. Sodium transport through the amiloride-sensitive Na-Mg pathway of hamster red cells.

    Xu, W; Willis, J S


    Previous work showed that in hamster red cells the amiloride-sensitive (AS) Na+ influx of 0.8 mmol/liter cells/hr is not mediated by Na-H exchange as in other red cells, but depends upon intracellular Mg2+ and can be increased by 40-fold by loading cells with Mg2+ to 10 mM. The purpose of this study was to verify the connection of AS Na+ influx with Na-dependent, amiloride-sensitive Mg2+ efflux and to utilize AS Na+ influx to explore that pathway. Determination of unidirectional influx of Na+ and net loss of Mg2+ in parallel sets of cells showed that activation by extracellular [Na+] follows a simple Michaelis-Menten relationship for both processes with a Km of 105-107 mM and that activation of both processes is sigmoidally dependent upon cytoplasmic [Mg2+] with a [Mg2+]0.5 of 2.1-2.3 mM and a Hill coefficient of 1.8. Comparison of Vmax for both sets of experiments indicated a stoichiometry of 2 Na:1 Mg. Amiloride inhibits Na+ influx and Mg2+ extrusion in parallel (Ki = 0.3 mM). Like Mg2+ extrusion, amiloride-sensitive Na+ influx shows an absolute requirement for cytoplasmic ATP and is increased by cell swelling. Hence, amiloride-sensitive Na+ influx in hamster red cells appears to be through the Na-Mg exchange pathway. There was no amiloride-sensitive Na+ efflux in hamster red cells loaded with Na+ and incubated with high [Mg2+] in the medium with or without external Na+, nor with ATP depletion. Hence, this is not a simple Na-Mg exchange carrier.

  4. Effect of heat treatment on the microstructures and damping properties of biomedical Mg-Zr alloy

    Tsai, Ming-Hung [Department of Mechanical Engineering and Graduate Institute of Mechanical and Precision Engineering, National Kaoshiung University of Applied Sciences, Kaoshiung 807, Taiwan (China); Department of Dentistry, Chang Yin dental clinic, No.46-1, Yangming St., Banqiao City, Taipei County 220, Taiwan (China); Research Center for Biomedical Devices, Taipei Medical University, Taipei 110, Taiwan (China); Chen, May-Show [Research Center for Biomedical Devices, Taipei Medical University, Taipei 110, Taiwan (China); School of Oral Hygiene, College of Oral Medicine, Taipei Medical University, Taipei 110, Taiwan (China); Department of Dentistry, Taipei Medical University Hospital, Taipei 110, Taiwan (China); Lin, Ling-Hung [Department of Dentistry, Taipei Medical University Hospital, Taipei 110, Taiwan (China); School of Dentistry, College of Oral Medicine, Taipei Medical University, Taipei 110, Taiwan (China); Lin, Ming-Hong [Department of Mechanical Engineering and Graduate Institute of Mechanical and Precision Engineering, National Kaoshiung University of Applied Sciences, Kaoshiung 807, Taiwan (China); Wu, Ching-Zong, E-mail: [Department of Dentistry, Taipei Medical University Hospital, Taipei 110, Taiwan (China); School of Dentistry, College of Oral Medicine, Taipei Medical University, Taipei 110, Taiwan (China); Ou, Keng-Liang, E-mail: [Research Center for Biomedical Devices, Taipei Medical University, Taipei 110, Taiwan (China); Graduated Institute of Biomedical Materials and Engineering, Taipei Medical University, Taipei 110, Taiwan (China); Research Center for Biomedical Implants and Microsurgery Devices, Taipei Medical University, Taipei 110, Taiwan (China); Yu, Chih-Hua [Research Center for Biomedical Devices, Taipei Medical University, Taipei 110, Taiwan (China); Research Center for Biomedical Implants and Microsurgery Devices, Taipei Medical University, Taipei 110, Taiwan (China)


    Research highlights: > When the as-quenched Mg-1Zr alloy was aged at temperatures ranging from 200 deg. C to 500 deg. C, a microstructural transformation sequence was found to be {alpha}-Mg {yields} ({alpha}-Mg + twin{sub dense}) {yields} ({alpha}-Mg + twin{sub loose}) {yields} ({alpha}-Mg + {alpha}-Zr). > As the as-quenched Mg-1Zr alloy was subjected to aging treatment at 300 deg. C for 16 h, it exhibited the maximum damping properties. > The twin structure plays a crucial role in increasing the damping capacity of the Mg-1Zr alloy. - Abstract: In this study, we elucidated the effect of heat treatment on the microstructures and damping properties of the biomedical Mg-1 wt% Zr (K1) alloy by optical microscopy, transmission electron microscopy, energy-dispersive X-ray spectrometry, and experimental model analysis. The following microstructural transformation occurred when the as-quenched (AQ, i.e., solution heat treated and quenched) K1 alloy was subjected to aging treatment in the temperature range 200-500 deg. C: {alpha}-Mg {yields} ({alpha}-Mg + twin{sub dense}) {yields} ({alpha}-Mg + twin{sub loose}) {yields} ({alpha}-Mg + {alpha}-Zr). This microstructural transformation was accompanied by variations in the damping capacity. The damping properties of the AQ K1 alloy subjected to aging treatment at 300 deg. C for 16 h were the best among those of the alloys investigated in the present study. The presence of twin structures in the alloy matrix was thought to play a crucial role in increasing the damping capacity of the K1 alloy. Hence, we state that a combination of solution treatment and aging is an effective means of improving the damping capacity of biomedical K1 alloys.

  5. Reliability enhancement due to in-situ post-oxidation of sputtered MgO barrier in double MgO barrier magnetic tunnel junction

    Yoshida, Chikako; Noshiro, Hideyuki; Yamazaki, Yuichi; Sugii, Toshihiro


    We have investigated the effects of in-situ post-oxidation (PO) of a sputtered MgO barrier in a double-MgO-barrier magnetic tunnel junction (MTJ) and found that the short error rate was significantly reduced, the magnetoresistance (MR) ratio was increased approximately 18%, and the endurance lifetime was extend. In addition, we found that the distribution of breakdown number (a measure of endurance) exhibits trimodal characteristics, which indicates competition between extrinsic and intrinsic failures. This improvement in reliability might be related to the suppression of Fe and Co diffusion to the MgO barrier, as revealed by electron energy-loss spectroscopy (EELS) analysis.

  6. Wear Behavior of Al-Mg2Si Cast In-situ Composite: Effect of Mg2Si Different Volume Fractions

    Ghiasinejad, J.; Emamy, M.; Ghorbani, M. R.; Malekan, A.


    Al-Mg2Si in situ composites are great candidates for automobile brake discs due to their low density, reasonably high young's modulus and low thermal expansion coefficient. Thus, understanding wear properties of this composite is of a great importance. In this study wear behavior of an in-situ Al-Mg2Si composite, prepared from a simple casting route, has been investigated using a pin-on-disc configuration concerning the effect of Mg2Si volume fractions, 15, 20 and 25% respectively. It was found that the weight loss increases with increase in reinforce volume fraction which can be due to a coarse morphology of primary Mg2Si particles. It was found that the variations of weight loss with sliding distance comprise different regimes of which the mechanisms are discussed.


    Z.M. Zhang; C.J. Xu; X.F. Guo


    An icosahedral Mg3 YZn6 quasicrystalline phase can be produced in Mg-Zn-Y system alloys when a proper amount of Zn and Y is contained, and it is feasible to prepare the quasicrystal phase-reinforced low-density magnesium alloy. In this article, phase constituents and the effect of reciprocating extrusion on microstructures and properties of the as-cast Mg-6.4Zn-1.1 Y alloy are analyzed. The microstructure of the as-cast Mg-6.4Zn-1.1 Y alloy consists of the a-Mg solid solution, icosahedral Mg3 YZn6 quasicrystal, and Mg3 Y2Zn3 and MgZn2 compounds. After the alloy was reciprocatingly extruded for four passes, grains were refined, Mg3 Y2 Zn3 and MgZn2 phases dissolved into the matrix, whereas, Mg3YZn6 precipitated and distributed uniformly. The alloy possesses the best performance at this state; the tensile strength, yield strength, and elongation are 323.4 MPa, 258.2 MPa, and 19.7%, respectively. In comparison with that of the as-cast alloy, the tensile strength, yield strength, and elongation of the reciprocatingly extruded alloy increase by 258.3%, 397.5%, and 18 times, respectively. It is concluded that reciprocating extrusion can substantially improve the properties of the as-cast Mg-6.4Zn-1.1 Y alloy, particularly for elongation. The high performance of the Mg-6.4Zn-1.1 Y alloy after reciprocating extrusion can be attributed to dispersion strengthening and grain-refined microstructures.

  8. Single-dose rasburicase 6 mg in the management of tumor lysis syndrome in adults.

    McDonnell, Anne M; Lenz, Kristi L; Frei-Lahr, Debra A; Hayslip, John; Hall, Philip D


    Rasburicase is currently approved at a dosage of 0.15-0.2 mg/kg once/day for 5 days in pediatric patients with cancer to lower plasma uric acid concentrations and manage tumor lysis syndrome (TLS). Information on rasburicase dosing in adults is limited, with some data on using rasburicase as a single dose instead of multiple daily doses. Therefore, we evaluated the efficacy of a single dose of rasburicase for preventing or managing TLS in adults. We collected retrospective data for 11 adults with hematologic malignancies who received a single 6-mg dose of rasburicase. All patients received intravenous hydration with urinary alkalinization and allopurinol; however, due to adverse reactions, two patients received short courses of allopurinol. Only patients at high risk for TLS (e.g., large tumor burden, increasing uric acid concentration) or those with TLS received rasburicase. The single dose of rasburicase 6 mg resulted in a median 0.0773-mg/kg dose (range 0.0232-0.1361 mg/kg). The single 6-mg dose rapidly lowered uric acid concentrations in 10 of the 11 patients. The median uric acid concentration of 11.7 mg/dl (range 7.4-17.4 mg/dl) declined to 2.0 mg/dl (range 0.5-15.4 mg/dl) within a day after rasburicase administration (p=0.022). In these 10 patients, uric acid concentrations remained low despite subsequent chemotherapy, and none required additional rasburicase doses. The only patient who did not respond to the single 6-mg rasburicase dose was a morbidly obese man (259 kg, body mass index 87 kg/m2) who subsequently responded to an additional dose of rasburicase 12 mg. These results warrant further investigation of a single 6-mg dose of rasburicase in adults with TLS or at high-risk for developing TLS.

  9. MgB sub 2 superconductor: a review

    Mollah, S; Chaudhuri, B K


    Synthesis, structure and properties of the most intensively studied newly discovered intermetallic binary superconductor MgB sub 2 have been reviewed up to October, 2002. It has a hexagonal unit cell with cell parameters a approx 3.1432 A and c approx 3.5193 A. MgB sub 2 bulk samples synthesized under high pressure (approx 3.5 GPa) and high temperature (approx 1000 degC) has density approx 2.63 g/cm sup 3. The normal state carriers of MgB sub 2 are holes which have been established from the positive thermoelectric power and Hall coefficient measurements. The external pressure decreases the critical temperature (T sub c) with dT sub c /dP in the range of -1 to -2 K/GPa. The T sub c decreases rapidly by the doping of Mn, Li, Co, C, Al, Ni and Fe but increases slightly by Zn doping. However, no significant change of T sub c is observed by the doping of Si and Be. It is further noticed that the anisotropic ratio gamma(= H sub c sub 2 sup a sup b /H sub c sub 2 sup c) approx 1-5 with lower critical field (H sub c ...

  10. Direct observation of increasing CO2 in the Weddell Gyre along the Prime Meridian during 1973-2008

    van Heuven, Steven M. A. C.; Hoppema, Mario; Huhn, Oliver; Slagter, Hans A.; de Baar, Hein J. W.


    The World Ocean takes up a large portion of the anthropogenic CO2 emitted into the atmosphere. Determining the resulting increase in dissolved inorganic carbon (C-T, expressed in mu mol kg(-1)) is challenging, particularly in the sub-surface and deep Southern Ocean where the time rate of change of

  11. Direct observation of increasing CO2 in the Weddell Gyre along the Prime Meridian during 1973-2008

    van Heuven, Steven M. A. C.; Hoppema, Mario; Huhn, Oliver; Slagter, Hans A.; de Baar, Hein J. W.


    The World Ocean takes up a large portion of the anthropogenic CO2 emitted into the atmosphere. Determining the resulting increase in dissolved inorganic carbon (C-T, expressed in mu mol kg(-1)) is challenging, particularly in the sub-surface and deep Southern Ocean where the time rate of change of C

  12. Thermoelectric properties of Al-doped Mg2Si thin films deposited by magnetron sputtering

    Chen, Zhi-jian; Zhou, Bai-yang; Li, Jian-xin; Wen, Cui-lian


    The Al-doped Mg2Si thin films were fabricated by two-target alternative magnetron sputtering technique, and the influences of different Al doping contents on the thermoelectric properties of Al-doped Mg2Si thin films were investigated. The compositions, crystal structures, electronic transport properties and thermoelectric properties of the thin films were examined using energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), Hall coefficient measurement and Seebeck coefficient measurement system, respectively. The EDS results show that the thin films doped with Al target sputtering power of 30 W, 60 W and 90 W have the Al content of 0.68 at.%, 1.56 at.% and 2.85 at.%, respectively. XRD results indicate that the diffraction peaks of Mg2Si become stronger with increasing Al dopant. The results of Hall coefficient measurement and Seebeck coefficient measurement system reveal that all the samples are n-type. The conductivities of Al-doped Mg2Si thin films are significantly greater than that of undoped Mg2Si thin film, and increase with increasing Al doping content. With the increase of temperature, the absolute value of the Seebeck coefficients of Mg2Si base thin films increase firstly and then decrease. The maximum power factor obtained is 3.8 mW m-1 k-2 for 1.56 at.% Al-doped Mg2Si thin film at 573 K.

  13. Modern and Cenozoic records of magnesium behaviour from foraminiferal Mg isotopes

    P. A. E. Pogge von Strandmann


    Full Text Available Magnesium is an element critically involved in the carbon cycle, because weathering of Ca–Mg silicates removes atmospheric CO2 into rivers, and formation of Ca–Mg carbonates in the oceans removes carbon from the ocean–atmosphere system. Hence the Mg cycle holds the potential to provide valuable insights into Cenozoic climate-system history, and the shift during this time from a greenhouse to icehouse state. We present Mg isotope ratios for the past 40 Myr using planktic foraminifers as an archive. Modern foraminifera, which discriminate against elemental and isotopically heavy Mg during calcification, show no correlation between the Mg isotope composition (δ26Mg and temperature, Mg / Ca or other parameters such as carbonate saturation (Δ CO3. However, inter-species isotopic differences imply that only well-calibrated single species should be used for reconstruction of past seawater. Seawater δ26Mg inferred from the foraminiferal record decreased from ~ 0‰ at 15 Ma, to −0.83‰ at the present day, which coincides with increases in seawater lithium and oxygen isotope ratios. It strongly suggests that neither Mg concentrations nor isotope ratios are at steady-state in modern oceans, given its ~ 10 Myr residence time. From these data, we have developed a dynamic box model to understand and constrain changes in Mg sources to the oceans (rivers and Mg sinks (dolomitisation and hydrothermal alteration. Our estimates of seawater Mg concentrations through time are similar to those independently determined by pore waters and fluid inclusions. Modelling suggests that dolomite formation and the riverine Mg flux are the primary controls on the δ26Mg of seawater, while hydrothermal Mg removal and the δ26Mg of rivers are more minor controls. Using riverine flux and isotope ratios inferred from the 87Sr / 86Sr record, the modelled Mg removal by dolomite formation shows minima in the Oligocene and at the present day (with decreasing trends from 15

  14. Materials science of Mg-Ni-based new hydrides

    Orimo, S.; Fujii, H. [Hiroshima Univ. (Japan). Faculty of Integrated Arts and Sciences


    One of the advantageous functional properties of Mg alloys (or compounds) is to exhibit the reversible hydriding reaction. In this paper, we present our systematic studies regarding the relationship between nanometer- or atomistic-scale structures and the specific hydriding properties of the Mg-Ni binary system, such as(1) nanostructured (n)-Mg{sub 2}Ni, (2) a mixture of n-Mg{sub 2}Ni and amorphous (a)-MgNi,(3) pure a-MgNi, and(4) n-MgNi{sub 2}. Further studies on(5) an a-MgNi-based system for clarifying the effect of the short-range ordering on the structural and hydriding properties and(6) a MgNi{sub 2}-based system for synthesizing the new Laves phase structure are also presented. The materials science of Mg-Ni-based new hydrides will provide indispensable knowledge for practically developing the Mg alloys as hydrogen-storage materials. (orig.)

  15. Factors Influencing MgO Content of RE-Mg Nodularizing Alloy%REMg球化剂中MgO含量的影响因素

    杨宇鹏; 肖勇


    The effect of Mg in nodularizing alloy was introduced.When the total content of Mg was constant,the formation of MgO reduced the content of the effective Mg that would influence the nodularizing capability of the nodualrizing alloy.The source of MgO in nodularizing alloy was analyzed as follows:the MgO formed during the melting process of the nodularizing alloy and the MgO formed during the analysis sample preparing process.It was pointed out after analyzing two cases:(1) the MgO content of nodularizing alloy is the main factor influencing its nodularzing capability,therefore the MgO content should be reduced by improving its melting process; (2)In order to ensure the veracity of MgO content test it's necessary to use correct sample preparing method.%介绍了Mg在球化剂中的作用.当w(Mg总)一定时,MgO的生成降低了w(Mg有效)的含量,影响到球化剂的球化能力.分析了球化剂中MgO的来源:球化剂熔炼过程中产生MgO、在制取分析样品过程中产生MgO.通过2个案例的分析,指出:(1)球化剂中MgO含量的高低是影响其球化能力的主要因素,应通过改进熔炼工艺来降低w(MgO)量;(2)为确保球化剂中w(MgO)量检测的准确性,应采用正确的样品制备方法.

  16. メカニカルグラインディング(MG)処理したNiO特性評価

    井上, 左知男; 渡辺, 国昭; Abe, Takayuki


    Atomization, crystallinity, and electrochemical characteristics of powdery NiO treated by mechanical grinding (MG) were examined. XRD analysis and TEM observations showed that MG generated rapid atomization of NiO particles in the initial stage of treatment up to 20 h and further MG resulted in general atomization. Electrochemical measurements showed that the specific capacitance of treated NiO increased with increase in MG time. After 190 h of MG treatment, the specific capacitance was ca. 6...

  17. Dielectric properties of nanocrystalline Co-Mg ferrites

    Sharma, Jyoti, E-mail: [Department of Physics, University of Rajasthan, Jaipur (India); Sharma, Neha [Department of Physics, VEC Lakhanpur, Sarguja University, Ambikapur (C.G.) (India); Parashar, Jyoti; Saxena, V.K.; Bhatnagar, D. [Department of Physics, University of Rajasthan, Jaipur (India); Sharma, K.B. [Department of Physics, S. S. Jain Subodh P. G. College, Jaipur (India)


    Nanocrystalline powder samples with chemical formula Co{sub x}Mg{sub 1−x}Fe{sub 2}O{sub 4} (x = 0, 0.2, 0.4, 0.6, 0.8 and 1.0) have been synthesized by sol–gel auto combustion method using citric acid as fuel agent. The rietveld refinement study of x-ray diffraction patterns confirmed the spinel single phase formation for all samples. Dielectric constant (ε′), dielectric loss tangent (tan δ) and AC conductivity of Co{sub x}Mg{sub 1−x}Fe{sub 2}O{sub 4} ferrite nanoparticles have been measured at room temperature in the frequency range from 1000 Hz to 120 MHz. The dielectric dispersion observed at lower frequency region is attributed to Maxwell–Wagner two layer model, which is in agreement with Koops phenomenological theory. The observed results have been explained by polarization which is attributed to the electron exchange between Fe{sup 2+} and Fe{sup 3+} ions. The temperature variation of ε′ and tanδ for some particular frequencies were studied. The rapid increase in ε′ and tan δ has been explained using thermally activated electron exchange between Fe{sup 2+} ↔ Fe{sup 3+} and Co{sup 2+} ↔ Co{sup 3+} ions at adjacent octahedral sites. The role of interfacial polarization has been focused to explain the high dispersion in ε′ and tanδ with temperature observed at low frequencies. - Graphical abstract: (a) TEM image of Co{sub 0.4}Mg{sub 0.6}Fe{sub 2}O{sub 4} shows the nano size of the synthesized ferrite particles and (b) Dielectric constant behavior with frequency of Co{sub x}Mg{sub 1−x}Fe{sub 2}O{sub 4} ferrite.

  18. Room temperature ferromagnetism in Mg-doped ZnO nanoparticles

    Singh, Jaspal, E-mail:; Vashihth, A. [Department of Applied Sciences, Chandigarh University, Gharuan, Mohali-140413 (India); Gill, Pritampal Singh; Verma, N. K. [Nano Research Lab, School of Physics and Materials Science, Thapar University, Patiala-147 004 (India)


    Zn{sub 1-x}Mg{sub x}O (x = 0, 0,10) nanoparticles were successfully synthesized using sol-gel method. X-ray diffraction (XRD) confirms that the synthesized nanoparticles possess wurtzite phase having hexagonal structure. Morphological analysis was carried out using transmission electron microscopy (TEM) which depicts the spherical morphology of ZnO nanoparticles. Energy dispersive spectroscopy (EDS) showed the presence of Mg in ZnO nanoparticles. Electron spin resonance (ESR) signal was found to be decreasing with increasing of Mg-doping concentration. The room temperature ferromagnetism was observed in undoped and Mg-doped ZnO nanoparticles. The increase of Mg-doping concentration resulted in decrease of saturation magnetization value which could be attributed to decrease of oxygen vacancies present in host nanoparticles.

  19. Synthesis, characterization and antibacterial property of ZnO:Mg nanoparticles

    Kompany, A.; Madahi, P.; Shahtahmasbi, N.; Mashreghi, M.


    Sol-gel method was successfully used for the synthesis of ZnO nanoparticles (NPs) doped with different concentrations of Mg and the structural, optical and antibacterial properties of the nanoparticles were studied. The synthesized ZnO:Mg powders were characterized using x-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transformation Infrared (FTIR) and UV-Vis spectroscopy. It was revealed that the samples have hexagonal Wurtzite structure, and the phase segregation takes place for 15% Mg content. TEM images show that the average size of the particles is about 50 nm. Also, the antibacterial activities of the nanoparticles were tested against Escherichia coli (Gram negative) cultures. ZnO:Mg nanofluid showed good antibacterial activity which increases with the increase of NPs concentration, and decreases slightly with the amount of Mg.

  20. Photosynthetic capacity, nutrient status, and growth of maize (Zea mays L.) upon MgSO4 leaf-application.

    Jezek, Mareike; Geilfus, Christoph-Martin; Bayer, Anne; Mühling, Karl-Hermann


    The major plant nutrient magnesium (Mg) is involved in numerous physiological processes and its deficiency can severely reduce the yield and quality of crops. Since Mg availability in soil and uptake into the plant is often limited by unfavorable soil or climatic conditions, application of Mg onto leaves, the site with highest physiological Mg demand, might be a reasonable alternative fertilization strategy. This study aimed to investigate, if MgSO4 leaf-application in practically relevant amounts can efficiently alleviate the effects of Mg starvation in maize, namely reduced photosynthesis capacity, disturbed ion homeostasis and growth depression. Results clearly demonstrated that Mg deficiency could be mitigated by MgSO4 leaf-application as efficiently as by resupply of MgSO4 via the roots in vegetative maize plants. Significant increases in SPAD values and net rate of CO2-assimilation as well as enhanced shoot biomass have been achieved. Ion analysis furthermore revealed an improvement of the nutrient status of Mg-deficient plants with regard to [Mg], [K], and [Mn] in distinct organs, thereby reducing the risk of Mn-toxicity at the rootside, which often occurs together with Mg deficiency on acid soils. In conclusion, foliar fertilization with Mg proved to be an efficient strategy to adequately supply maize plants with Mg and might hence be of practical relevance to correct nutrient deficiencies during the growing season.

  1. Ethylbenzene dehydrogenation over FeOx/(Mg,Zn)(Al)O catalysts derived from hydrotalcites: Role of MgO as basic sites

    Balasamy, Rabindran J.


    A series of Mg3-xZnxFe0.5Al0.5 mixed oxide catalysts derived from hydrotalcites were tested in the ethylbenzene dehydrogenation to styrene in He atmosphere at 550 °C. The catalysts were prepared by coprecipitation from the nitrates of metal components followed by calcination to mixed oxides at 550 °C. A part of Mg2+ in Mg 3Fe0.5Al0.5 mixed oxide was replaced with Zn2+ to test the effect of MgO as the support. The mixed oxides were composed of periclase and spinel-type compounds with a high surface area of 100-180m2gcat-1. Mössbauer and XPS measurements indicated the presence of Fe3+ on the catalysts and H2-TPR measurement suggested that the dehydrogenation reaction is catalyzed by the reduction-oxidation between Fe3+/Fe2+. The activity of Mg3-xZnxFe0.5Al0.5 mixed oxide decreased with increasing x, indicating an important role of MgO on the activity. Both CO2-TPD measurements as well as IR measurements of adsorbed CO2 clearly indicated the presence of basic sites of Mg 2+O2- on the catalysts. It seems that the combination of Mg2+O2- and Fe3+ was essential for the catalytic activity. It is concluded that the surface base sites generated on O2- bound Mg2+ near Fe3+ sites are responsible for H+-abstraction; the dehydrogenation of ethylbenzene was initiated by the H+ abstraction on Mg2+O2- basic sites, and accelerated by the reduction-oxidation of Fe3+/Fe2+ active species. © 2011 Elsevier B.V.

  2. Direct inelastic scattering of NO from MgO(100)

    Kolodney, E.; Baugh, D.; Powers, P. S.; Reisler, H.; Wittig, C.


    Angular and internal state distributions are reported for NO molecules scattered from cleaved, single-crystal MgO(100) at several kinetic energies: 0.56⩾KE⩽0.90 eV, and surface temperatures: 300⩽ Ts⩽760 K. Rotational distributions can be characterized by low- and high- J "Boltzmann-like" components. When Ts=760 K, a pronounced increase in the high- J excitation was observed. NO(ν″=1) was undetectable ([ν″ = 1]/[ν″ =0] < 5×10 -3) at KE=0.76 eV and Ts=540 K.

  3. Improvement of inverted type organic solar cells performance by incorporating Mg dopant into hydrothermally grown ZnO nanorod arrays

    Ginting, Riski Titian [School of Applied Physics, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor (Malaysia); Yap, Chi Chin, E-mail: [School of Applied Physics, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor (Malaysia); Yahaya, Muhammad [School of Applied Physics, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor (Malaysia); Mat Salleh, Muhamad [Institute of Microengineering and Nanoelectronics (IMEN), Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor (Malaysia)


    Highlights: • Mg-doped ZnO nanorod arrays were synthesized by hydrothermal method. • Growth of ZnO nanorods was strongly correlated to Mg concentration. • The PCE of device with optimum Mg concentration increased by 225%. • The mechanism of PCE improvement by Mg doping was revealed. -- Abstract: The Mg concentration dependence of the performance of inverted type organic solar cells based on Mg-doped ZnO nanorod arrays and poly(3-hexylthiophene) (P3HT) has been investigated. The Mg dopants with various concentrations (0, 1, 3 and 5 at.%) were introduced during the hydrothermal growth of the ZnO nanorod arrays on fluorine-doped tin oxide (FTO) glass substrate. The P3HT was deposited onto Mg-doped ZnO nanorod arrays by spin coating technique, followed by deposition of Ag as anode using magnetron sputtering technique. The length and density of Mg-doped ZnO nanorods increased, whereas the diameter decreased with the Mg concentration. The short circuit current density (J{sub sc}) and open circuit voltage (V{sub oc}) improved with increasing of Mg concentration up to 3 at.%, which could be attributed to increased interfacial area for more efficient exciton dissociation and reduced charge recombination as a result of lower number of oxygen interstitials which act as electron traps in ZnO. However, the J{sub sc} and V{sub oc} started to decrease at Mg concentration of 5 at.%, mainly due to poor infiltration of P3HT into the high-density 5 at.% Mg-doped ZnO nanorod arrays and increase of Mg dopant-related trapping centers. The highest power conversion efficiency of 0.36 ± 0.02% was achieved at Mg doping concentration of 3 at.%, an enhancement of 225% as compared to that based on undoped ZnO nanorod arrays.

  4. Synthesis of mixed ceramic Mg(x)Zn(1-x)O nanofibers via Mg2+ doping using sol-gel electrospinning.

    Aykut, Yakup; Parsons, Gregory N; Pourdeyhimi, Behnam; Khan, Saad A


    We report on the synthesis of tuned energy band gap Mg(x)Zn(1-x)O nanofibers (NFs) with different Mg(2+) content via the sol-gel electrospinning (ES) technique wherein the addition of the doping material affects not only the morphologies of as-spun ZnAc/PVA and MgAc/ZnAc/PVA nanofibers but also the crystal microstructure and optical properties of calcined ZnO and Mg(x)Zn(1-x)O nanofibers. Following an appropriate aqueous solution preparation of magnesium acetate (MgAc) and zinc acetate (ZnAc) with poly(vinyl alcohol) (PVA), electrospinning is performed and then as-spun nanofibers are calcined in an air atmosphere at 600 °C for 3 h. As-spun and calcined nanofiber diameters and morphologies are evaluated with scanning (SEM) and transmission (TEM) electron microscopies, whereas crystalline microstructural interpretations of ZnO and Mg(x)Zn(1-x)O are conducted with wide-angle X-ray diffraction spectra (XRD). Surface chemical composition and elemental evaluation of calcined nanofibers are examined with X-ray photoelectron spectroscopy (XPS), and optical properties and crystal defect analyses of the calcined nanofibers are conducted with photoluminescence spectra (PL). We observe a sharp reduction in fiber diameter upon calcination as a result of the removal of organic species from the fibers and conversion of ceramic precursors into ceramic nanofibers, and the appearance of a range of fiber morphologies from "bead in a string" to "sesame seed" coverage depending on fiber composition. Because Zn(2+) and Mg(2+) have similar ionicity and atomic radii, some Zn(2+) atoms are replaced by Mg(2+) atoms in the crystals, leading to a change in the properties of crystal lattices. The band gap energy of the calcined fibers increases significantly with addition of Mg(2+) along with an increase in the ultraviolet (UV) photoluminescence emission of the fibers.

  5. Electrochemical formation of Mg-Li-Ca alloys by codeposition of Mg, Li and Ca from LiCl-KCl-MgCl2-CaCl2 melts.

    Yan, Yong De; Zhang, Mi Lin; Xue, Yun; Han, Wei; Cao, Dian Xue; Jing, Xiao Yan; He, Li Yi; Yuan, Yi


    This work presents electrochemical formation of Mg-Li-Ca alloys via codeposition of Mg, Li and Ca on a molybdenum electrode in KCl-LiCl-MgCl(2)-CaCl(2) melts at 943 K. Cyclic voltammograms (CVs) showed that the underpotential deposition (UPD) of calcium on pre-deposited magnesium leads to the formation of a liquid Mg-Ca alloy, and the succeeding underpotential deposition of lithium on pre-deposited Mg-Ca alloy leads to the formation of a liquid Mg-Li-Ca solution. Chronopotentiometric measurements indicated that the codepositon of Mg, Li and Ca occurs at current densities more negative than -0.31 A cm(-2) in LiCl-KCl-MgCl(2) (5 wt%) melts containing 1 wt% CaCl(2). Chronoamperograms demonstrated that the onset potential for the codeposition of Mg, Li and Ca is -2.200 V, and the codeposition of Mg, Li and Ca is formed when the applied potentials are more negative than -2.200 V. X-Ray diffraction (XRD) indicated that Mg-Li-Ca alloys with different phases were formed via galvanostatic electrolysis. The microstructures of typical alpha and beta phases of Mg-Li-Ca alloys were characterized by optical microscope (OM) and scanning electron microscopy (SEM). The analysis of energy dispersive spectrometry (EDS) showed that the element Ca mainly distributes along grain boundary in Mg-Li-Ca alloys. The results of inductively coupled plasma analysis determined that the chemical compositions of Mg-Li-Ca alloys correspond with the phase structures of XRD patterns, and the lithium and calcium contents of Mg-Li-Ca alloys depend on the concentrations of MgCl(2) and CaCl(2).

  6. Decay of a narrow and high spin {sup 24}Mg + {sup 24}Mg resonance

    Salsac, M.-D. [IPHC, Universite Louis Pasteur, CNRS-IN2P3, Strasbourg (France)], E-mail:; Haas, F.; Courtin, S. [IPHC, Universite Louis Pasteur, CNRS-IN2P3, Strasbourg (France); Algora, A. [INR, Debrecen (Hungary); Beck, C. [IPHC, Universite Louis Pasteur, CNRS-IN2P3, Strasbourg (France); Beghini, S. [Universita di Padova and INFN, Padova (Italy); Behera, B.R. [INFN Laboratori Nazionali di Legnaro, Legnaro (Italy); Chapman, R. [University of the West of Scotland, Paisley (United Kingdom); Corradi, L. [INFN Laboratori Nazionali di Legnaro, Legnaro (Italy); Dombradi, Z. [INR, Debrecen (Hungary); Farnea, E. [Universita di Padova and INFN, Padova (Italy); Fioretto, E.; Gadea, A. [INFN Laboratori Nazionali di Legnaro, Legnaro (Italy); Jenkins, D.G. [University of York, York (United Kingdom); Latina, A. [INFN Laboratori Nazionali di Legnaro, Legnaro (Italy); Lebhertz, D. [IPHC, Universite Louis Pasteur, CNRS-IN2P3, Strasbourg (France); Lenzi, S. [Universita di Padova and INFN, Padova (Italy); Liang, X. [University of the West of Scotland, Paisley (United Kingdom); Marginean, N. [INFN Laboratori Nazionali di Legnaro, Legnaro (Italy); Montagnoli, G. [Universita di Padova and INFN, Padova (Italy)] (and others)


    The {sup 24}Mg + {sup 24}Mg reaction has been studied at the Legnaro Tandem at a CM bombarding energy of 45.7 MeV where a narrow and high spin resonance has been reported previously. The decay of the resonance into the inelastic and fusion-evaporation channels has been investigated. The ON and OFF resonance decay yields have been measured using, for the inelastic channels, the fragment spectrometer PRISMA and the {gamma} array CLARA, and, for the fusion-evaporation channels, the Si array EUCLIDES and the {gamma} array GASP. Strong resonant effects have been observed in the inelastic channels involving the 2{sub 1}{sup +} and 4{sub 1}{sup +} states of the {sup 24}Mg ground state band. Weaker effects are also seen in certain fusion-evaporation channels. The properties of the studied resonance are in agreement with molecular model predictions. It is also proposed that the narrow and high spin {sup 24}Mg + {sup 24}Mg resonance corresponds to the formation of a fast rotating and highly prolate deformed {sup 48}Cr after a Jacobi shape transition and just before fission.

  7. Refinements in an Mg/MgH2/H2O-Based Hydrogen Generator

    Kindler, Andrew; Huang, Yuhong


    Some refinements have been conceived for a proposed apparatus that would generate hydrogen (for use in a fuel cell) by means of chemical reactions among magnesium, magnesium hydride, and steam. The refinements lie in tailoring spatial and temporal distributions of steam and liquid water so as to obtain greater overall energy-storage or energy-generation efficiency than would otherwise be possible. A description of the prior art is prerequisite to a meaningful description of the present refinements. The hydrogen-generating apparatus in question is one of two versions of what was called the "advanced hydrogen generator" in "Fuel-Cell Power Systems Incorporating Mg-Based H2 Generators" (NPO-43554), NASA Tech Briefs, Vol. 33, No. 1 (January 2009), page 52. To recapitulate: The apparatus would include a reactor vessel that would be initially charged with magnesium hydride. The apparatus would exploit two reactions: The endothermic decomposition reaction MgH2-->Mg + H2, which occurs at a temperature greater than or equal to 300 C, and The exothermic oxidation reaction MgH2 + H2O MgO + 2H2, which occurs at a temperature greater than or equal to 330 C.

  8. Mg Isotope Evolution During Water-Rock Interaction in a Carbonate Aquifer

    Zhang, Z.; Jacobson, A. D.; Lundstrom, C. C.; Huang, F.


    To better understand how Mg isotopes behave during weathering and aqueous transport, we used a Nu Plasma MC-ICP-MS to measure δ26Mg values (relative to DSM-3) in water samples along a 236 km flow path in the Madison aquifer of South Dakota, a confined carbonate aquifer recharging in the igneous Black Hills. We also analyzed local granite and dolomite samples to characterize the Mg isotope composition of source rocks constituting the recharge zone and aquifer, respectively. Repeated analyses of Mg standard solutions yielded external precisions (2σ) better than 0.1 permil for δ26Mg(CAM-1, - 2.584±0.071, n=13; UIMg-1, -2.217±0.087, n=9.). The Madison aquifer provides a unique opportunity to quantify Mg isotope effects during water-rock interaction because (1) fluids and rock have chemically equilibrated over a much longer timescale (up to ~15 kyr) than can be simulated in laboratory experiments and (2) previous studies have determined the rates and mass-balances of de- dolomitization and other geochemical reactions controlling solute evolution along the flow path. Reactions important for changing the concentration and isotope composition of Mg include dolomite dissolution, Mg-for- Na ion exchange, calcite precipitation, and isotope exchange. δ26Mg values within the recharge region (0-17 km along flow path) vary between -1.08 and -1.63 permil, and then remain essentially constant at -1.408±0.010 permil(1σ, 5 samples) from 17 to 189 km. A final sample at 236 km shows an increase to -1.09 permil. Either mixing between different recharge waters or rapid isotope exchange between infiltrating waters and dolomite could control δ26Mg variability between 0 and 17 km. Likewise, reactive transport modeling suggests that preferential uptake of 24Mg during Mg-for-Na ion exchange might cause an increase in δ26Mg between 189 and 236 km. However, unchanging δ26Mg values observed throughout most of the aquifer clearly demonstrate that Mg isotopes are not fractionated during

  9. Solution Fabrication of a Superconducting MgB2 Coated Conductor on Stainless Steel

    WANG Yin-Bo; CHEN Li-Ping; ZHANG Chen; WANG Yue; GUO Zheng-Shan; CHEN Yi-Ling; FENG Qing-Rong; GAN Zi-Zhao


    We report the solution fabrication of a MgB2 coated conductor on a stainless steel substrate. The precursor solution of Mg(BH4)2 diethyl ether is initially synthesized by refluxing the milled mixture of NaBH4 and MgCl2 in diethyl ether. Then the Mg(BH4)2 diethyl ether is spin coated on a stainless steel substrate and annealed in Mg vapor, which yields a homogeneous MgB2 coated conductor. X-ray diffraction indicates that the grown MgB2 coated conductor is polycrystalline. It has a superconducting transition temperature of 34-37K. The slope of the upper critical field Hc2 increases with decreasing temperature, and the extrapolated value of Hc2 (0) reaches ~28T. The critical current density estimated by the Bean model is Jc (25K, 0T)~106 A·cm-2. These parameters indicate that the solution method is potentially able to produce MgB2 coated conductors that can satisfy application purposes.%We report the solution fabrication of a MgB2 coated conductor on a stainless steel substrate.The precursor solution of Mg(BH4 )2 diethyl ether is initially synthesized by refluxing the milled mixture of NaBH4 and MgCl2 in diethyl ether.Then the Mg(BH4)2 diethyl ether is spin coated on a stainless steel substrate and annealed in Mg vapor,which yields a homogeneous MgB2 coated conductor.X-ray diffraction indicates that the grown MgB2 coated conductor is polycrystalline.It has a superconducting transition temperature of 34-37K.The slope of the upper critical field HC2 increases with decreasing temperature,and the extrapolated value of Hc2 (0)reaches ~28 T.The critical current density estimated by the Bean model is JC (25K,0 T)~1 06 parameters indicate that the solution method is potentially able to produce MgB2 coated conductors that can satisfy application purposes.

  10. Prolonged maternal amino acid infusion in late-gestation pregnant sheep increases fetal amino acid oxidation.

    Rozance, Paul J; Crispo, Michelle M; Barry, James S; O'Meara, Meghan C; Frost, Mackenzie S; Hansen, Kent C; Hay, William W; Brown, Laura D


    Protein supplementation during human pregnancy does not improve fetal growth and may increase small-for-gestational-age birth rates and mortality. To define possible mechanisms, sheep with twin pregnancies were infused with amino acids (AA group, n = 7) or saline (C group, n = 4) for 4 days during late gestation. In the AA group, fetal plasma leucine, isoleucine, valine, and lysine concentrations were increased (P < 0.05), and threonine was decreased (P < 0.05). In the AA group, fetal arterial pH (7.365 +/- 0.007 day 0 vs. 7.336 +/- 0.012 day 4, P < 0.005), hemoglobin-oxygen saturation (46.2 +/- 2.6 vs. 37.8 +/- 3.6%, P < 0.005), and total oxygen content (3.17 +/- 0.17 vs. 2.49 +/- 0.20 mmol/l, P < 0.0001) were decreased on day 4 compared with day 0. Fetal leucine disposal did not change (9.22 +/- 0.73 vs. 8.09 +/- 0.63 micromol x min(-1) x kg(-1), AA vs. C), but the rate of leucine oxidation increased 43% in the AA group (2.63 +/- 0.16 vs. 1.84 +/- 0.24 micromol x min(-1) x kg(-1), P < 0.05). Fetal oxygen utilization tended to be increased in the AA group (327 +/- 23 vs. 250 +/- 29 micromol x min(-1) x kg(-1), P = 0.06). Rates of leucine incorporation into fetal protein (5.19 +/- 0.97 vs. 5.47 +/- 0.89 micromol x min(-1) x kg(-1), AA vs. C), release from protein breakdown (4.20 +/- 0.95 vs. 4.62 +/- 0.74 micromol x min(-1) x kg(-1)), and protein accretion (1.00 +/- 0.30 vs. 0.85 +/- 0.25 micromol x min(-1) x kg(-1)) did not change. Consistent with these data, there was no change in the fetal skeletal muscle ubiquitin ligases MaFBx1 or MuRF1 or in the protein synthesis regulators 4E-BP1, eEF2, eIF2alpha, and p70(S6K). Decreased concentrations of certain essential amino acids, increased amino acid oxidation, fetal acidosis, and fetal hypoxia are possible mechanisms to explain fetal toxicity during maternal amino acid supplementation.

  11. Formation and Stability of Hollow MgO Nanoshells

    Krishnan, G.; Palasantzas, G.; Kooi, B.J.


    High temperature annealing of gas phase synthesized Mg nanoparticles surrounded by an MgO shell leads to formation of hollow MgO nanoshells due to the evaporation assisted Kirkendall effect. Under electron beam exposure in TEM, the (220) MgO facets reduce their high surface energy by forming cube fa

  12. cDNA library Table: mg [KAIKOcDNA[Archive

    Full Text Available mg NA mg-- p50 midgut fifth instar larval stage D3 mixed pBluescript SK- EcoR1 for ...5' Xho1for 3' sequenced from T3 primer (5' -> 3') AU001868-AU002476,BY916287-BY916543 mg[number],mg[number]_1 ...

  13. Statin-Induced Increases in Atrophy Gene Expression Occur Independently of Changes in PGC1α Protein and Mitochondrial Content.

    Craig A Goodman

    Full Text Available One serious side effect of statin drugs is skeletal muscle myopathy. Although the mechanism(s responsible for statin myopathy remains to be fully determined, an increase in muscle atrophy gene expression and changes in mitochondrial content and/or function have been proposed to play a role. In this study, we examined the relationship between statin-induced expression of muscle atrophy genes, regulators of mitochondrial biogenesis, and markers of mitochondrial content in slow- (ST and fast-twitch (FT rat skeletal muscles. Male Sprague Dawley rats were treated with simvastatin (60 or 80 mg·kg(-1·day(-1 or vehicle control via oral gavage for 14 days. In the absence of overt muscle damage, simvastatin treatment induced an increase in atrogin-1, MuRF1 and myostatin mRNA expression; however, these were not associated with changes in peroxisome proliferator gamma co-activator 1 alpha (PGC-1α protein or markers of mitochondrial content. Simvastatin did, however, increase neuronal nitric oxide synthase (nNOS, endothelial NOS (eNOS and AMPK α-subunit protein expression, and tended to increase total NOS activity, in FT but not ST muscles. Furthermore, simvastatin induced a decrease in β-hydroxyacyl CoA dehydrogenase (β-HAD activity only in FT muscles. These findings suggest that the statin-induced activation of muscle atrophy genes occurs independent of changes in PGC-1α protein and mitochondrial content. Moreover, muscle-specific increases in NOS expression and possibly NO production, and decreases in fatty acid oxidation, could contribute to the previously reported development of overt statin-induced muscle damage in FT muscles.

  14. Microstructures and Mechanical Properties of Al/Mg Alloy Multilayered Composites Produced by Accumulative Roll Bonding

    H.S.Liu; B.Zhang; G.P.Zhang


    Al/Mg alloy multilayered composites were produced successfully at the lower temperature (280℃) by accumulative roll bonding (ARB) processing technique. The microstructures of Al and Mg alloy layers were characterized by scanning electron microscopy and transmission electron microscopy. Vickers hardness and three-point bending tests were conducted to investigate mechanical properties of the composites. It is found that Vickers hardness, bending strength and stiffness modulus of the Al/Mg alloy multilayered composite increase with increasing the ARB pass. Delamination and crack propagation along the interface are the two main failure modes of the multilayered composite subjected to bending load. Strengthening and fracture mechanisms of the composite are analyzed.

  15. The three shapes of 32Mg

    Poves A.


    Full Text Available The N=20 and N=28 “islands of inversion” are described by large scale shell model calculations which mix configurations with different Nħω or equivalently with different number of particles promoted from the sd-shell to the pf -shell. We pay particular attention to the properties of the states at fix Nħω which turn out to be the real protagonists of the physics at N=20. In particular we study the appearance of spherical, deformed and superdeformed structures in 32Mg at fixed 0p-0h, 2p-2h and 4p-4h configurations. Finally we submit that the islands of deformation at N=20 and N=28 merge in the Magnesium isotopes

  16. Simultaneous polymerization of Mg and Zr alkoxides

    Mendez-Vivar, J.; Lara, V.H. [Univ. Autonoma Metropolitana-Iztapalapa, Depto. de Quimica, Mexico, D. F. (Mexico); Mendoza-Serna, R.; Ayala-Morales, A. [Facultad de Estudios Superiores Zaragoza, UNAM, Carrera de Ingenieria Quimica, Mexico, D. F. (Mexico); Bosch, P. [Inst. de Investigaciones en Materiales, UNAM Circuito Exterior, Mexico, D. F. (Mexico)


    The preparation of homogeneous MgO-ZrO{sub 2} ceramics by the sol-gel process is of interest because of its potential technological applications as dielectric materials in thin films and membranes. In this work we used magnesium methoxide and zirconium n-propoxide as precursors. The simultaneous polymerization of the alkoxides was performed via the sol-gel process, using acetylacetone (acacH) and isoeugenol (isoH) separately as the chelating agents, in order to control the hydrolysis and condensation steps. Spectroscopic studies have been performed on the sols, gels, xerogels and oxides, including Fourier transform infrared (FTIR) spectroscopy and small Angle X-ray Scattering (SAXS). (orig.)

  17. Mg II Absorbing Galaxies: Morphologies and Kinematics

    Churchill, C; Kacprzak, G G; Churchill, Chris; Steidel, Chuck; Kacprzak, Glenn


    In this contribution, we review our current knowledge of the properties of galaxies, and their extended halos, selected by MgII absorption in the spectra of background quasars. We then describe recent efforts to quantify the morphologies and orientations of galaxies and explore how these relate to the gas kinematics. In a sample of 26 galaxies, we find no clear connection between the orientation of the quasar line of sight through the galaxy and the velocity spread of the gas. However, it appears that the quantity of gas "stirred up" in the halo may be correlated to asymmetry in the galaxy morphology. Since the galaxies have fairly normal morphologies, this connection may suggest that galaxies with extended halos experienced an interaction or merging event a few dynamical times prior to the epoch of observation.

  18. Multiaxial magnetic ordering in NdMg

    Deldem, M; Galera, R M; Morin, P; Schmitt, D; Ouladdiaf, B


    NdMg is a cubic compound (CsCl-type) which orders antiferromagnetically at T sub N =61 K. The magnetization measurements show a second transition at T sub R =35 K. Over the whole order range, the powder neutron diffraction pattern can be indexed on the hypothesis of a collinear structure, the magnetic moments being parallel to the wave vector. The neutron diffraction experiments on a single crystal, under an applied magnetic field, establish that the transition at T sub R corresponds to a change from a collinear structure to a multiaxial one. The magnetic moments successively point along a fourfold axis, in the collinear structure, and along twofold axes in the multiaxial one. This sequence of magnetic structures is consistent with the coexistence of ferroquadrupolar gamma-couplings and antiferroquadrupolar epsilon-couplings. (author)

  19. Review: the effects of secular variation in seawater Mg/Ca on marine biocalcification

    J. B. Ries


    Full Text Available Synchronized transitions in the polymorph mineralogy of the major reef-building and sediment-producing calcareous marine organisms and abiotic CaCO3 precipitates (ooids, marine cements throughout Phanerozoic time is believed to have been caused by tectonically-induced variations in seawater molar Mg/Ca (>2="aragonite seas"; <2="calcite seas". Here, I review a series of experiments in which extant calcifying taxa were reared in experimental seawater formulated over the range of mMg/Ca ratios (1.0 to 5.2 that occurred throughout their geologic history.

    Aragonite-secreting bryopsidalean algae and scleractinian corals and calcite-secreting coccolithophores exhibited higher rates of calcification and growth in the experimental seawaters that favored their skeletal mineral. These results support the assertion that seawater Mg/Ca played an important role in determining which hypercalcifying marine organisms were the major reef-builders and sediment-producers throughout Earth history. The observation that primary production increased along with calcification in mineralogically-favorable seawater is consistent with the hypothesis that calcification promotes photosynthesis within autotrophs through the liberation of CO2.

    The Mg/Ca ratio of calcite secreted by the coccolithophores, coralline algae and reef-dwelling animals (crustacea, urchins, calcareous tube worms declined with reductions in seawater Mg/Ca. Calcifying microbial biofilms varied their mineral polymorph with seawater Mg/Ca (mMg/Ca<2=low Mg calc; mMg/Ca>2=arag+high Mg calc, suggesting a nearly abiotic mode of calcification. These results indicate that biomineralogical control can be partially overridden by ambient seawater Mg/Ca and suggests that modern high Mg calcite organisms probably secreted low Mg calcite in calcite seas of the past. Notably, Mg fractionation in autotrophic organisms was more strongly influenced by changes in

  20. Preparation of Mg-MgH2 flakes by planetary ball milling with stearic acid and their hydrogen storage properties

    Hong, Seong-Hyeon; Song, Myoung Youp


    Many studies preparing magnesium hydride using catalyst addition were performed, resulting in the preparation of additive-containing magnesium hydride. Preparation of a sample with a MgH2 phase without additives requires high pressure and high temperature and is time-demanding. In order to prepare an additive-free sample with a MgH2 phase, 90 wt% Mg+10 wt% MgH2 (named 90Mg+10MgH2) was milled under a hydrogen atmosphere with 6 wt% stearic acid as a process-controlling agent, which led to a formation of Mg-MgH2 flakes. The hydrogen storing and releasing properties of the prepared flakes were investigated and compared with those of purchased MgH2. A sample with a majority fraction of MgH2 phase was prepared by planetary ball milling of 90 Mg+10 MgH2 with 6 wt% stearic acid. The resultant particles of 90 Mg+10 MgH2 obtained after hydridingdehydriding cycling were much smaller and had significantly more cracks and defects than those of MgH2 after hydriding-dehydriding cycling. 90 Mg+10 MgH2 released 0.12 wt% hydrogen for 4 min, 3.70 wt% for 20 min, and 5.30 wt% for 60 min at 648 K at the first cycle.

  1. Effect of mischmetal and yttrium on microstructures and mechanical properties of Mg-Al alloy

    张诗昌; 魏伯康; 蔡启舟; 王立世


    The effect of yttrium and mischmetal(MMs) on the as-cast and solid solution treated structures of Mg-Al alloys with different Al-contents was investigated. The results show that the MMs in Mg-Al alloy existed in rodAl4 (Ce, La)compound while Y in Mg-Al alloy in polygonal Al2 Y compound. The amount of Mg17 Al12 in Mg-Al al-loy is decreased with increasing Y or MMs addition, and Mg17 Al12 intermetallic compound is changed from continu-ous network to discontinuous one. The Al4 (Ce, La) and Al2 Y compounds are not dissolved into Mg-Al alloy matrixduring solid solution treatment so that their high heat stability can be exhibited. The experiment of mechanical prop-erties indicate that elongation and impact toughness of the Mg-Al-Y alloy with polygonal Al2 Y compound are higherthan those of Mg-Al-MMs alloy with rod Al4 (Ce, La) compound.

  2. Magnesium-Based Sacrificial Anode Cathodic Protection Coatings (Mg-Rich Primers for Aluminum Alloys

    Michael D. Blanton


    Full Text Available Magnesium is electrochemically the most active metal employed in common structural alloys of iron and aluminum. Mg is widely used as a sacrificial anode to provide cathodic protection of underground and undersea metallic structures, ships, submarines, bridges, decks, aircraft and ground transportation systems. Following the same principle of utilizing Mg characteristics in engineering advantages in a decade-long successful R&D effort, Mg powder is now employed in organic coatings (termed as Mg-rich primers as a sacrificial anode pigment to protect aerospace grade aluminum alloys against corrosion. Mg-rich primers have performed very well on aluminum alloys when compared against the current chromate standard, but the carcinogenic chromate-based coatings/pretreatments are being widely used by the Department of Defense (DoD to protect its infrastructure and fleets against corrosion damage. Factors such as reactivity of Mg particles in the coating matrix during exposure to aggressive corrosion environments, interaction of atmospheric gases with Mg particles and the impact of Mg dissolution, increases in pH and hydrogen gas liberation at coating-metal interface, and primer adhesion need to be considered for further development of Mg-rich primer technology.

  3. A study on atomic diffusion behaviours in an Al-Mg compound casting process

    Liu, Yongning; Chen, Yiqing; Yang, Chunhui


    Al and Mg alloys are main lightweight alloys of research interest and they both have superb material properties, i.e., low density and high specific strength, etc. Being different from Al alloys, the corrosion of Mg alloys is much more difficult to control. Therefore to combine merits of these two lightweight alloys as a composite-like structure is an ideal solution through using Al alloys as a protective layer for Mg alloys. Compound casting is a realistic technique to manufacture such a bi-metal structure. In this study, a compound casting technique is employed to fabricate bi-layered samples using Al and Mg and then the samples are analysed using electron probe micro-analyzer (EPMA) to determine diffusion behaviours between Al and Mg. The diffusion mechanism and behaviours between Al and Mg are studied numerically at atomic scale using molecular dynamics (MD) and parametric studies are conducted to find out influences of ambient temperature and pressure on the diffusion behaviours between Al and Mg. The results obtained clearly show the effectiveness of the compound casting process to increase the diffusion between Al and Mg and thus create the Al-base protection layer for Mg.

  4. Estabilidad de tabletas de Rifampicina 300 mg

    Lisette Martínez Miranda


    Full Text Available Se realizó el estudio de estabilidad de las tabletas de rifampicina 300 mg. Se utilizó para la cuantificación del principio activo un método analítico desarrollado y validado por cromatografía líquida de alta resolución en fase reversa y detección ultravioleta. El estudio de estabilidad de las tabletas se efectuó mediante los métodos de vida útil y acelerado en condiciones isotérmicas; no se obtuvo una variación notable de la concentración en el tiempo de estudio y se demostró así la estabilidad química y térmica del principio activo, por lo que se proponen 2 años como fecha de vencimiento. La humedad relativa de 75, 84 y 92 % tuvo influencia en la estabilidad de la formulación en el período analizado.The stability study of rifampicin 300 mg was conducted. An analytical method developed and validated by high pressure liquid chromatography in reverse phase and ultraviolet detection was used for the quantification of the actives principle. The stability study of the tablets was conducted by the method of useful life and the accelerated method under isothermic conditions. There was no significant variation of the concentration during the time of study and, thus, the chemical and thermal stability of the active principle was proved. A period of 2 years was proposed as expiration date. A relative humidity of 75, 84 and 92% influenced on the stability of the formulation in the analyzed period.

  5. Evidence for beta -delayed neutron emission from /sup 31/Mg and /sup 32/Mg

    Zaidins, C S; De Saint-Simon, M; Détraz, C; Epherre-Rey-Campagnolle, Marcelle; Guillemaud, D; Klapisch, Robert; Langevin, M; Naulin, F; Thibault, C; Touchard, F


    Investigates the time spectrum of beta -delayed neutron emission from /sup 30-34/Na and their descendants using beta -neutron coincidence detection. The authors have been able to assign an upper limit of 0,4% to the probability of beta -delayed neutron emission, p/sub n/, from the /sup 30/Na daugher isotope /sup 30/Mg. In fitting the time spectra of beta -delayed neutrons from /sup 31/Na and /sup 32/Na, we find a definitive component from subsequent daughter decay as well. This provides evidence for beta -delayed neutron emission from /sup 31/Mg and /sup 32/Mg with P/sub n/ values of the order of 2% for each. (7 refs).

  6. [Mechanism of HL-60 cells apoptosis induced by proteasome inhibitor MG132].

    Zhou, Yong-Ming; Yu, Mei-Xia; Qiu, Yu-Zhen; Xing, Xiao-Lei; Yao, Chun-Hong; Bai, Ru-Jun


    The purpose of this study was to elucidate the apoptosis, apoptotic pathway of HL-60 cells induced by proteasome inhibitor MG132 and its effect on allogeneic mixed lymphocyte reaction. Apoptosis of HL-60 cells was detected by flow cytometry, the expression of P21, P27 and P53 proteins in HL-60 cells treated with MG132 was assayed by Western blot. The HL-60 cells were treated with 1 µmol/L MG132 for 48 h, and irradiated by 75 Gy of (60)Co γ-ray, but their antigenicity was preserved. The effect of irradiated HL-60 cells treated with MG132 on proliferation of peripheral blood mononuclear cells (PBMNC) was measured by CCK-8 method. The results showed that the apoptotic rate of MG132-treated HL-60 cells increased in dose-and time-dependent manner. No significant changes in MG132-induced apoptosis were observed after inhibiting caspase-8 and caspase-9 pathway. The expression of P21 and P27 protein increased after treatment of HL-60 cells with MG132. CCK-8 test showed that HL-60 cells induced with low-dose of MG132 displayed the enhancing effect on proliferation of PBMNC. It is concluded that high dose of MG132 can induce the apoptosis of HL-60 cells, and has direct killing effect on HL-60 cells, but this inducing apoptotic effect on HL-60 cells can not be realized through caspase-8 and caspase-9 pathway. The P21 and P27 protein may be involved in MG132 induced HL-60 cell apoptosis. Low dose of MG132 promotes the proliferation of PBMNC in healthy individuals and enhance the immunity of organism.

  7. Mg(2+)-induced conformational changes in the btuB riboswitch from E. coli.

    Choudhary, Pallavi K; Sigel, Roland K O


    Mg(2+) has been shown to modulate the function of riboswitches by facilitating the ligand-riboswitch interactions. The btuB riboswitch from Escherichia coli undergoes a conformational change upon binding to its ligand, coenzyme B12 (adenosyl-cobalamine, AdoCbl), and down-regulates the expression of the B12 transporter protein BtuB in order to control the cellular levels of AdoCbl. Here, we discuss the structural folding attained by the btuB riboswitch from E. coli in response to Mg(2+) and how it affects the ligand binding competent conformation of the RNA. The btuB riboswitch notably adopts different conformational states depending upon the concentration of Mg(2+). With the help of in-line probing, we show the existence of at least two specific conformations, one being achieved in the complete absence of Mg(2+) (or low Mg(2+) concentration) and the other appearing above ∼0.5 mM Mg(2+). Distinct regions of the riboswitch exhibit different dissociation constants toward Mg(2+), indicating a stepwise folding of the btuB RNA. Increasing the Mg(2+) concentration drives the transition from one conformation toward the other. The conformational state existing above 0.5 mM Mg(2+) defines the binding competent conformation of the btuB riboswitch which can productively interact with the ligand, coenzyme B12, and switch the RNA conformation. Moreover, raising the Mg(2+) concentration enhances the ratio of switched RNA in the presence of AdoCbl. The lack of a AdoCbl-induced conformational switch experienced by the btuB riboswitch in the absence of Mg(2+) indicates a crucial role played by Mg(2+) for defining an active conformation of the riboswitch.

  8. Intercalation of Mg-ions in layered V2O5 cathode materials for rechargeable Mg-ion batteries

    Sørensen, Daniel Risskov; Johannesen, Pætur; Christensen, Christian Kolle

    The development of functioning rechargeable Mg-ion batteries is still in its early stage, and a coarse screening of suitable cathode materials is still on-going. Within the intercalation-type cathodes, layered crystalline materials are of high interest as they are known to perform well in Li......-ion intercalation batteries and are also increasingly being explored for Na-ion batteries. Here, we present an investigation of the layered material orthorhombic V2O5, which is a classical candidate for an ion-intercalation material having a high theoretical capacity1. We present discharge-curves for the insertion...

  9. Removal of K+, Na+, Ca2+, and Mg2+ from saline-alkaline water using the microalga Scenedesmus obliquus

    Yao, Zongli; Ying, Chengqi; Lu, Jianxue; Lai, Qifang; Zhou, Kai; Wang, Hui; Chen, Ling


    The capability of Scenedesmus obliquus to remove cations (K+, Na+, Ca2+, Mg2+) from saline-alkaline water was investigated at different salinities (0, 5, 10, 15, 20, 25) and carbonate alkalinities (0, 5, 10, 15, 20, 25, 30, 35 mmol/L). K+, Na+, Ca2+, and Mg2+ in saline-alkaline water were efficiently removed by S. obliquus. The maximum removal of the cations (29.37 mg for K+, 185.85 mg for Na+, 23.07 mg for Ca2+, 66.14 mg for Mg2+) occurred at salinity 25. The maximum removal of K+ (2.28 mg), Na+ (6.62 mg), Ca2+ (1.01 mg), and Mg2+ (0.62 mg) occurred at carbonate alkalinities of 25 mmol/L for K+, 35 mmol/L for Na+, 20 mmol/L for Ca2+, and 25 mmol/L for Mg2+, respectively. Under a salinity stress, the concentration of Na+ in S. obliquus increased significantly, while that of K+ decreased significantly. The concentrations of Ca2+ and Mg2+ decreased as well. The ratios of K+/Na+, Ca2+/Na+, and Mg2+/Na+ were significantly lower in all salinity treatments than those of the control. Under alkaline stress, the concentrations of Na+ and K+ in S. obliquus decreased significantly and the ratios of K+/Na+, Ca2+/Na+, and Mg2+/Na+ were significantly higher in all treatments than in the control. Moreover, the concentrations of Ca2+ and Mg2+ in S. obliquus at alkalinities of 5-10 mmol/L were significantly higher than those of the other treatments. The removal of Na+ by S. obliquus mainly occurs through biosorption, and Mg2+ and Ca2+ were removed through both biosorption and bioaccumulation.

  10. The phase analysis of spark plasma sintered MgB2 after ball milling.

    Kang, Deuk-Kyun; Kim, Dong-Woong; Kim, Cheol-Jin; Ahn, In-Shup


    Mg and amorphous B powders below 10 and 3 micro meter were used as raw materials, and mixed by planetary-mill for 9 hours at argon atmosphere. MgB2 bulk was fabricated at the various temperatures by Spark Plasma Sintering. In the sintering process, mixed powders were sintered in graphite mold, at the pressure of 55 Mpa. The fabricated MgB2 samples were evaluated with XRD, EDS, FE-SEM, PPMS. MgB2, MgO and Fe phases were observed from XRD result. In the results, MgO and Fe were impurity which may affect superconducting properties of MgB2 samples, and it's distribution could be confirmed from EDS mapping result. In order to confirm the formation of MgB2 phase, DTA was used as heating rate of 10 degrees C/min at Ar atmosphere from room temperature to 1200 degrees C. In the PPMS result, the Tc (critical temperature) was about 21 K, and the density of spark plasma sintered samples increased to 1.87 g/cm3 by increasing sintering temperature.

  11. Microstructure and magnetic properties of FePt/MgO multilayers deposited by RF magnetron sputtering

    Xiaoli Li; Fang Wang; Fengxian Jiang; Xiaohong Xu; Haishun Wu


    FePt (50 rim) and [FePt(a nm)/MgO(b nm)]5/glass (a=1, 2, 3; b=1, 2, 3)films Were prepared by radio frequency (RF) magnetron sputtering technique, and then were annealed at 600℃ for 30 min. The effect of MgO layer thickness on the structures and magnetic properties of the FePt/MgO multilayers was investigated. The coercivities and inter-grain interactions of the FePt/MgO films were decreased, yet the degree of (001) texturing drastically increased with the increase in MgO layer thickness when the FePt layer thickness was fixed. Thus, the FePt/MgO films with appropriate coercivities, high perpendicular anisotropy, and weak inter- grain interactions were obtained by controlling the MgO layer thickness. Overall, these results indicate that the FePt/MgO nanos- tructured films are promising candidates for future high-density perpendicular recording media. C 2008 University of Science and Technology Beijing. All fights reserved.

  12. Preparation and characterization of MgO nanorods coated with SnO2.

    Kim, Hyunsu; Jin, Changhyun; Kim, Hyoun Woo; Lee, Chongmu


    MgO nanorods have been grown by thermal evaporation of Mg3N2 powders on Si (100) substrates coated with gold (Au) thin films. The MgO nanorods grown on Al2O3 (0001) were 0.1-0.2 microm in diameter and up to a few tens of micrometers in length. MgO/SnO2 coaxial nanorods have also been prepared by atomic layer deposition (ALD) of SnO2 onto the nanorods. Transmission electron microscopy (TEM) and X-ray diffraction (XRD) analysis results indicate that the MgO-cores and the SnO2 shells of the annealed coaxial nanorods are of a single crystalline nature with cubic and orthorhombic structures, respectively. The photoluminescence (PL) spectroscopy analysis results show that SnO2 coating slightly increases the PL emission intensity of MgO nanorods. The PL emission of the SnO2-coated MgO nanorods is found to be considerably enhanced by thermal annealing and to strongly depend on the annealing atmosphere. The PL emission intensity of the MgO/SnO2 coaxial nanorods has been significantly increased by annealing in a reducing atmosphere. The origin of the PL enhancement by annealing in a reducing atmosphere is discussed on the basis of energy-dispersive X-ray spectroscopy analyses.

  13. Microstructure and Mechanical Properties of Mg-Al-Ca-Nd Alloys Fabricated by Gravity Casting


    The aims of this study are to investigate the effects of Nd addition in the Mg-Al-Ca alloys on microstructure and mechanical properties. Microstructure of as-cast Mg-5Al-3Ca alloy containing Nd consists of α-Mg matrix,eutectic phase and Al-Nd rich intermetallic compound. As Nd addition was increased, α-Mg matrix morphology was changed from dendritic to equiaxed grains and average value of grain size was decreased. Nd addition to Mg-5Al-3Ca based alloys resulted in the formation of Al-Nd rich intermetallic compounds at grain boundary and α-Mg matrix grains. And these Al-Nd rich intermetallic compounds were dispersed homogeneously. In these alloys, two kinds of eutectic phases were observed, i.e. coarse irregular-shape structure at grain boundary and fine needle-shape structure in the α-Mg matrix grain. It is found that the ultimate strength showed the maximum value of 271 MPa at Mg-5Al-3Ca-2Nd alloy and elongation was decreased as the addition of Nd was increased.

  14. Electrochemical behavior of Mg-Al-Pb alloy in 3.5% NaCl solution

    文利; 余琨; 房洪杰; 熊汉青; 尹翔; 朱化龙; 马家骥; 姜大越


    An investigation on electrochemical behavior of Mg-5%Pb alloy, Mg-6%Al alloy and Mg-6%Al-5%Pb alloy (mass fraction) in 3.5% NaCl (mass fraction) solution was conducted using electrochemical measurements and corroded morphology observation, in which solid solution and the as-aged state of each alloy were compared to discuss the influence mechanism of lead and aluminium on the electrochemical properties of alloys. The X-ray diffraction (XRD) analysis was performed to make microstructure characterization. The electrochemical results indicate that the corrosion of Mg-5%Pb alloy is predominated by homogeneous pitting and dissolution of PbCl2film due to Clions attack, while corrosion crevice propagates along grain boundaries in solid solution of Mg-6%Al alloy and the micro galvanic corrosion also plays vital role in Mg17Al12phase containing experimental alloys.The co-existence of lead and aluminium in magnesium alloy increases corrosion current density and electrochemical activity as well. The comparison between solid solution and the as-aged state demonstrates that Mg2Pb and Mg17Al12somewhat increase corrosion resistance but lighten anodic polarization by facilitating corrosion product flaking off.

  15. Impact of interface manipulation of oxide on electrical transport properties and low-frequency noise in MgO/NiFe/MgO heterojunctions

    Li, Jian-wei [School of Materials Science and Engineering, Shanghai University, Shanghai 200072 (China); School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Zhao, Chong-jun; Feng, Chun; Yu, Guang-hua [School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Zhou, Zhongfu [School of Materials Science and Engineering, Shanghai University, Shanghai 200072 (China)


    Low-frequency noise and magnetoresistance in sputtered-deposited Ta(5 nm)/MgO (3 nm)/NiFe(10 nm)/MgO(3 nm)/Ta(3 nm) films have been measured as a function of different annealing times at 400°C. These measurements did not change synchronously with annealing time. A significant increase in magnetoresistance is observed for short annealing times (of the order of minutes) and is correlated with a relatively small reduction in 1/f noise. In contrast, a significant reduction in 1/f noise is observed for long annealing times (of the order of hours) accompanied by a small change in magnetoresistance. After annealing for 2 hours, the 1/f noise decreases by three orders of magnitude. Transmission electron microscopy and slow positron annihilation results implicate the cause being micro-structural changes in the MgO layers and interfaces following different annealing times. The internal vacancies in the MgO layers gather into vacancy clusters to reduce the defect density after short annealing times, whereas the MgO/NiFe and the NiFe/MgO interfaces improve significantly after long annealing times with the amorphous MgO layers gradually crystallizing following the release of interfacial stress.

  16. Effect of MgCl2 addition on the sintering behavior of MgAl2O4 spinel and formation of nano-particles

    Mohammadi F.


    Full Text Available In this paper, the effect of MgCl2 addition on the sintering behavior of MgAl2O4 spinel produced via oxide mixture method was investigated. For this reason, the stoichiometric mixture of magnesite and calcined alumina as raw materials was calcined at 1100°C. The calcined mixture was milled, pressed and then, fired at 1300 and 1500°C after addition of various amounts of MgCl2. Besides, the physical properties, phase composition and microstructure of fired samples were investigated. The results showed that MgCl2 addition has great effect on the densification and particle size of spinel. Besides, MgCl2 addition increases the amount of spinel phase at all firing temperatures. Due to the decomposition of MgCl2 and then formation of ultra-fine MgO particles, the nano-sized spinel is formed on the surface of the larger spinel particles.

  17. The Enhancement of Mg Corrosion Resistance by Alloying Mn and Laser-Melting

    Youwen Yang


    Full Text Available Mg has been considered a promising biomaterial for bone implants. However, the poor corrosion resistance has become its main undesirable property. In this study, both alloying Mn and laser-melting were applied to enhance the Mg corrosion resistance. The corrosion resistance, mechanical properties, and microstructure of rapid laser-melted Mg-xMn (x = 0–3 wt % alloys were investigated. The alloys were composed of dendrite grains, and the grains size decreased with increasing Mn. Moreover, Mn could dissolve and induce the crystal lattice distortion of the Mg matrix during the solidification process. Mn ranging from 0–2 wt % dissolved completely due to rapid laser solidification. As Mn contents further increased up to 3 wt %, a small amount of Mn was left undissolved. The compressive strength of Mg-Mn alloys increased first (up to 2 wt % and then decreased with increasing Mn, while the hardness increased continuously. The refinement of grains and the increase in corrosion potential both made contributions to the enhancement of Mg corrosion resistance.

  18. Corrosion of Mg alloy AZ91D in the presence of living cells.

    Seuss, F; Seuss, S; Turhan, M C; Fabry, B; Virtanen, S


    Mg and Mg alloys are of interest for biodegradable implants as they readily corrode in biological fluids, and dissolved Mg ions are nontoxic. Even though it is well known that Mg dissolution leads to pH increase in the surroundings, the effect of the corrosion-induced alkalization on the biological environment has not been studied in detail. We therefore explored the interactions between corrosion-induced pH increase and cell growth on Mg alloy AZ91D surface. Cell adhesion and spreading on the alloy surface is unimpeded initially. However, with time a large fraction of cells de-adhere. We attribute this to the observed increase of the pH in the cell culture medium in the process of alloy dissolution. Cytotoxicity tests with HeLa cells grown on glass surfaces confirm that cell death increases with increasing alkalinity of the cell culture medium. We also show that a the cells that adhere on the Mg alloy surface act as a corrosion-blocking surface layer. In consequence, a slower pH increase in the medium takes place when the alloy surface is covered with cells. Electrochemical impedance spectroscopy measurements (EIS) verify that a cell layer slows down the corrosion process.

  19. Ageing processes in Al-Cu-Mg alloys with different Cu/Mg ratios

    Macchi, C. [IFIMAT, UNCentro and CONICET, Pinto, Tandil (Argentina); Somoza, A. [IFIMAT, UNCentro and CICPBA, Pinto, Tandil (Argentina); Ferragut, R.; Dupasquier, A. [LNESS and CNISM, Politecnico di Milano, Como (Italy); Polmear, I.J. [Emeritus Professor, Department of Materials Engineering, Monash University, Melbourne, Vic. (Australia)


    Three age-hardenable Al-Cu-Mg alloys with different Cu/Mg ratios were studied by means of positron annihilation lifetime spectroscopy and Vickers hardness as a function of the artificial ageing time at 175 C. Complementary information on the decomposition sequence was obtained by means of differential scanning calorimetry. The results are discussed in terms of the different structures that are formed during the precipitation sequence of the supersaturated solid solution. (copyright 2009 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)



    The objective of the present work is to study the casting characteristics of various Al-Li alloys, which include fluidity and strengths of the alloys and their interaction with cast molds. Materials investigated are Al-Li-Mg and Al-Li-Cu-Mg alloys with Li content of 2.5 wt%. The results show that sand molds with resin binders are good for Al-Li casting. Ceramic coatings can further reduce the metal-mold interactions. However, the permeability is also reduced by coating. The fluidity of Li-bea...

  1. Porous composite materials ZrO{sub 2}(MgO)-MgO for osteoimplantology

    Buyakov, Ales, E-mail: [Institute of Strength Physics and Materials Science SB RAS, Tomsk, 634055 (Russian Federation); National Research Tomsk State University, Tomsk, 634050 (Russian Federation); Litvinova, Larisa, E-mail:; Shupletsova, Valeria, E-mail: [Immanuel Kant Baltic Federal University, Kaliningrad (Russian Federation); Kulbakin, Denis, E-mail: [Tomsk Cancer Research Institute, Tomsk, 634050 (Russian Federation); Kulkov, Sergey, E-mail: [Institute of Strength Physics and Materials Science SB RAS, Tomsk, 634055 (Russian Federation); National Research Tomsk State University, Tomsk, 634050 (Russian Federation); National Research Tomsk Polytechnic University, Tomsk, 634050 (Russian Federation)


    The pore structure and phase composition of ceramic composite material ZrO{sub 2}(Mg)-MgO at different sintering temperatures were studied. The main mechanical characteristics of the material were determined and it was shown that they are close to the characteristics of natural bone tissues. It was shown that material structure has a positive effect on the pre-osteoblast cells proliferation. In-vitro studies of pre-osteoblast cells, cultivation on material surface showed a good cell adhesion, proliferation and differentiation of MMSC by osteogenic type.




    Full Text Available In this work, powders of three different compositions, each having 34 SiO2-14.5 P2O5-1 CaF2-0.5 MgF (% wt and ratio of CaO/MgO varying from 11.5:1 to 1:11.5 were thoroughly mixed and melted under oxy-acetylene flame in a fire clay crucible that made the glass formation cheaper in time and cost. The melt of each composition was quenched in water to form three different glasses. Every glass was sintered at 950°C to form three glass ceramics named G1, G2 and G3 respectively. To study the dissolution behavior, each sample was immersed in a simulated body fluid (SBF for 2, 5, 10, 20 and 25 days at room temperature. Thin film XRD analysis revealed that the samples with larger CaO/MgO ratio exhibited better bioactivity. pH of SBF increased efficiently in case of G1 whereas in case of G2 and G3, this increase was slower due to greater amount of MgO. The concentrations of Ca, P, Mg and Si ions were measured by Atomic Absorption Spectroscopy. EDS analysis showed the increase in P and Ca ions and presence of C in G1 after 5 days immersion and after 10 days, in case of G2 indicating the higher formation rate of hydroxycarbonate Apatite layer in G1 as compared to G2 due to greater CaO/MgO ratio whereas in G3 Mg-hydroxycarbonate apatite (Ca(Mg5(CO3(PO43(OH (heneuite layer was recognized after 20 days showing the least bioactivity due to very large amount of Mg and the least CaO/MgO ratio.

  3. Effect of excess Mg and Excess Nb incorporation into the B-site of pyrochlore in the Pb-Mg-Nb-O system

    Mergen, A.


    Full Text Available In the Pb-Mg-Nb-O system, excess Mg and excess Nb incorporation into the B-site of PMN pyrochlore were investigated along the compositons of Pb1.83Mg0.29+xNb1.71-xO6.39-1.5x where x=0.1, 0.2, 0.3, 0.4, 0.522 and Pb1.83Mg0.29-xNb1.71+xO6.39+1.5x where x=0.1, 0.2, 0.29 respectively. Excess Mg incorporation led to the formation of perovskite and excess Nb resulted in formation of Pb2Nb2O7 monoclinic pyrochlore. The densities of the PMN pyrochlore-PMN perovskite mixtures decreased with an increase in Mg concentration. The relative permittivity of the mixtures increased with decreasing pyrochlore content. The effect of pyrochlore on the permittivity follows the Weiner’s mixture rule up to a pyrochlore content of 50 vol%.

    Se investigó la incorporación en lugares B de pirocloro PMN de un exceso de Mg y un exceso de Nb. En el sistema Pb-Mg-Nb-O2 las composiciones analizadas fueron Pb1.83Mg0.29+xNb1.71-xO6.39-1.5x donde x=0.1, 0.2, 0.3, 0.4, 0.522 y en Pb1.83Mg0.29-xNb1.71+xO6.39+1.5x donde x= 0.1, 0.2,0.29. El exceso de Mg condujo a la formación de perovskita y el exceso de Nb resultó en la formación del pirocloro monolínico, Pb2Nb2O7. La densidad de la mezcla de PMN pirocloro-perovskita dismunuye con el aumento de la concentración de Mg. La permitividad dieléctrica de las mezclas aumenta con la disminución del contenido de pirocloro. El efecto del pirocloro sobre la permitividad sigue la regla de mezclas de Weiner hasta conenidos de pirocloro del 50%.

  4. Localized increase of tissue oxygen tension by magnetic targeted drug delivery

    Liong, Celine; Ortiz, Daniel; Ao-ieong, Eilleen; Navati, Mahantesh S.; Friedman, Joel M.; Cabrales, Pedro


    Hypoxia is the major hindrance to successful radiation therapy of tumors. Attempts to increase the oxygen (O2) tension (PO2) of tissue by delivering more O2 have been clinically disappointing, largely due to the way O2 is transported and released by the hemoglobin (Hb) within the red blood cells (RBCs). Systemic manipulation of O2 transport increases vascular resistance due to metabolic autoregulation of blood flow to prevent over oxygenation. This study investigates a new technology to increase O2 delivery to a target tissue by decreasing the Hb-O2 affinity of the blood circulating within the targeted tissue. As the Hb-O2 affinity decreases, the tissue PO2 to satisfy tissue O2 metabolic needs increases without increasing O2 delivery or extraction. Paramagnetic nanoparticles (PMNPs), synthetized using gadolinium oxide, were coated with the cell permeable Hb allosteric effector L35 (3,5-trichlorophenylureido-phenoxy-methylpropionic acid). L35 decreases Hb affinity for O2 and favors the release of O2. The L35-coated PMNPs (L35-PMNPs) were intravenously infused (10 mg kg-1) to hamsters instrumented with the dorsal window chamber model. A magnetic field of 3 mT was applied to localize the effects of the L35-PMNPs to the window chamber. Systemic O2 transport characteristics and microvascular tissue oxygenation were measured after administration of L35-PMNPs with and without magnetic field. The tissue PO2 in untreated control animals was 25.2 mmHg. L35-PMNPs without magnetic field decreased tissue PO2 to 23.4 mmHg, increased blood pressure, and reduced blood flow, largely due to systemic modification of Hb-O2 affinity. L35-PMNPs with magnetic field increased tissue PO2 to 27.9 mmHg, without systemic or microhemodynamic changes. These results indicate that localized modification of Hb-O2 affinity can increase PO2 of target tissue without affecting systemic O2 delivery or triggering O2 autoregulation mechanisms. This technology can be used to treat local hypoxia and to

  5. Mechanical and corrosion properties of biodegradable Mg-1.5Mn-1Ca-xSr alloys

    Sun, X.; Sun, S. Y.; Ning, Y. H.; Ning, Y. T.


    The mechanical properties and corrosion mechanism of both as-cast and solution-naturally age (T4) treated Mg-1.5Mn-1Ca-xSr alloys were investigated. The results showed that Sr is helpful to decrease grain size and increase the strength. The corrosion process of alloys was mainly determined by the quantity and distribution of second phases. Mg17Sr2, α-Mn and Ca-Sr phases acted as cathodes accelerated the corrosion of Mg2Ca anodic phase and α-Mg matrix. However, continuous distributed Mg17Sr2 was beneficial to resist the happening of localized corrosion because of its barrier effect. T4 treatment could significantly improve the mechanical properties and corrosion resistance of Mg alloys because of the dissolution of Mg2Ca phase and the dispersive distribution of Mg17Sr2 and α-Mn phases.

  6. The Influence of MgH2 on the Assessment of Electrochemical Data to Predict the Degradation Rate of Mg and Mg Alloys

    Wolf-Dieter Mueller


    Full Text Available Mg and Mg alloys are becoming more and more of interest for several applications. In the case of biomaterial applications, a special interest exists due to the fact that a predictable degradation should be given. Various investigations were made to characterize and predict the corrosion behavior in vitro and in vivo. Mostly, the simple oxidation of Mg to Mg2+ ions connected with adequate hydrogen development is assumed, and the negative difference effect (NDE is attributed to various mechanisms and electrochemical results. The aim of this paper is to compare the different views on the corrosion pathway of Mg or Mg alloys and to present a neglected pathway based on thermodynamic data as a guideline for possible reactions combined with experimental observations of a delay of visible hydrogen evolution during cyclic voltammetry. Various reaction pathways are considered and discussed to explain these results, like the stability of the Mg+ intermediate state, the stability of MgH2 and the role of hydrogen overpotential. Finally, the impact of MgH2 formation is shown as an appropriate base for the prediction of the degradation behavior and calculation of the corrosion rate of Mg and Mg alloys.

  7. The influence of MgH2 on the assessment of electrochemical data to predict the degradation rate of Mg and Mg alloys.

    Mueller, Wolf-Dieter; Hornberger, Helga


    Mg and Mg alloys are becoming more and more of interest for several applications. In the case of biomaterial applications, a special interest exists due to the fact that a predictable degradation should be given. Various investigations were made to characterize and predict the corrosion behavior in vitro and in vivo. Mostly, the simple oxidation of Mg to Mg2+ ions connected with adequate hydrogen development is assumed, and the negative difference effect (NDE) is attributed to various mechanisms and electrochemical results. The aim of this paper is to compare the different views on the corrosion pathway of Mg or Mg alloys and to present a neglected pathway based on thermodynamic data as a guideline for possible reactions combined with experimental observations of a delay of visible hydrogen evolution during cyclic voltammetry. Various reaction pathways are considered and discussed to explain these results, like the stability of the Mg+ intermediate state, the stability of MgH2 and the role of hydrogen overpotential. Finally, the impact of MgH2 formation is shown as an appropriate base for the prediction of the degradation behavior and calculation of the corrosion rate of Mg and Mg alloys.

  8. Effect of organic ligands on Mg partitioning and Mg isotope fractionation during low-temperature precipitation of calcite in the absence of growth rate effects

    Mavromatis, Vasileios; Immenhauser, Adrian; Buhl, Dieter; Purgstaller, Bettina; Baldermann, Andre; Dietzel, Martin


    Calcite growth rate has been previously shown to be the dominating parameter controlling both Mg partitioning and Mg isotope fractionation during calcite growth. In natural calcite precipitation environments - characterized by abundant organic material - the presence of dissolved organic molecules may affect these two parameters. In order to assess the role of organic molecules, steady state calcite growth experiments have been performed at 25 °C, 1 bar pCO2 and constant, within analytical uncertainty growth rate (rp = 10-7.4 mol m-2 s-1) in the presence of aqueous Mg and six organic ligands in the concentration range from 0.01 to 10 mM. The organic ligands used in this study are: (i) acetic acid, (ii) citric acid, (iii) glutamic acid, (iv) salycilic acid, (v) glycine, and (vi) ethylenediaminetetraacetic acid (EDTA). These contain one or more carboxyl- and amino-groups that are commonly present in natural organic substances found in lacustrine, fluvial, soil, cave, as well as in marine and earliest diagenetic porewater environments. Results shown here indicate that the presence of these carboxyl- and amino-groups promotes an increase in the partition coefficient of Mg in calcite (DMg = (Mg/Ca)calcite/(Mg/Ca)fluid) that can be attributed to their adsorption onto the calcite surfaces and the subsequent reduction of the active sites of growth. This increase of DMg values as a function of the supersaturation degree of calcite in the fluid phase can be described by the linear equation:

  9. First-Principles Investigation of Phase Stability, Electronic Structure and Optical Properties of MgZnO Monolayer

    Changlong Tan


    Full Text Available MgZnO bulk has attracted much attention as candidates for application in optoelectronic devices in the blue and ultraviolet region. However, there has been no reported study regarding two-dimensional MgZnO monolayer in spite of its unique properties due to quantum confinement effect. Here, using density functional theory calculations, we investigated the phase stability, electronic structure and optical properties of MgxZn1−xO monolayer with Mg concentration x range from 0 to 1. Our calculations show that MgZnO monolayer remains the graphene-like structure with various Mg concentrations. The phase segregation occurring in bulk systems has not been observed in the monolayer due to size effect, which is advantageous for application. Moreover, MgZnO monolayer exhibits interesting tuning of electronic structure and optical properties with Mg concentration. The band gap increases with increasing Mg concentration. More interestingly, a direct to indirect band gap transition is observed for MgZnO monolayer when Mg concentration is higher than 75 at %. We also predict that Mg doping leads to a blue shift of the optical absorption peaks. Our results may provide guidance for designing the growth process and potential application of MgZnO monolayer.

  10. Moderately increased protein intake predominately from egg sources does not influence whole body, regional, or muscle composition responses to resistance training in older people.

    Iglay, H B; Apolzan, J W; Gerrard, D E; Eash, J K; Anderson, J C; Campbell, W W


    The effects of increased dietary protein on resistance training (RT)-induced changes in body composition and skeletal muscle fiber size are uncertain in older people. We hypothesized that the ingestion of more animal-based foods, especially eggs, to achieve a higher protein intake would enhance RT-induced changes in body composition. West Lafayette, IN. 36 older people (age 61 +/- 1 y; mean +/- SEM). Subjects completed RT three d/wk for 12 weeks, and consumed omnivorous diets that contained either 0.9 +/- 0.1 (lower protein) or 1.2 +/- 0.0 (higher protein) g protein x kg(-1) x d(-1) (12 +/- 3 and 17 +/- 5% of energy intakes, respectively), with the higher protein intake achieved by consuming more eggs, meats, and dairy foods. The lower and higher protein diets contained 213 +/- 21 and 610 +/- 105 mg cholesterol/d, respectively. Strength, body composition, serum lipid-lipoprotein profile, urinary creatinine, skeletal muscle fiber type and size. Among all subjects, over time (i.e. with RT) body weight was unchanged, lean mass (1.1 +/- 0.2 kg) increased, and fat mass (-1.4 +/- 0.2 kg) decreased (all changes P change from baseline. Serum total and LDL cholesterol decreased (P resistance training in older people.

  11. Mechanisms of antibacterial activity of MgO: non-ROS mediated toxicity of MgO nanoparticles towards Escherichia coli.

    Leung, Yu Hang; Ng, Alan M C; Xu, Xiaoying; Shen, Zhiyong; Gethings, Lee A; Wong, Mabel Ting; Chan, Charis M N; Guo, Mu Yao; Ng, Yip Hang; Djurišić, Aleksandra B; Lee, Patrick K H; Chan, Wai Kin; Yu, Li Hong; Phillips, David Lee; Ma, Angel P Y; Leung, Frederick C C


    The toxicity of metal oxide nanomaterials and their antimicrobial activity is attracting increasing attention. Among these materials, MgO is particularly interesting as a low cost, environmentally-friendly material. The toxicity of MgO, similar to other metal oxide nanomaterials, is commonly attributed to the production of reactive oxygen species (ROS). We investigated the toxicity of three different MgO nanoparticle samples, and clearly demonstrated robust toxicity towards Escherichia coli bacterial cells in the absence of ROS production for two MgO nanoparticle samples. Proteomics data also clearly demonstrate the absence of oxidative stress and indicate that the primary mechanism of cell death is related to the cell membrane damage, which does not appear to be due to lipid peroxidation.

  12. Effect of Mg substitution on electromagnetic properties of NiCuZn ferrite

    Sujatha, Ch.; Venugopal Reddy, K.; Sowri Babu, K.; RamaChandra Reddy, A.; Buchi Suresh, M.; Rao, K. H.


    Mg substituted NiCuZn ferrites were prepared through sol-gel method using polyvinyl alcohol (PVA) as a chelating agent. The samples after annealing at 500 °C to remove PVA were sintered at 950 °C for 1 h. The structural and electromagnetic properties of the samples were investigated. All the samples showed single phase spinel structure with increased lattice constant as a function of Mg concentration. The morphology reveals polyhedral shaped grains with increased grain size as a function of Mg composition. Dielectric parameters showed low values at higher frequencies. The initial permeability increased with Mg substitution in place of Ni in accordance with the microstructure. The samples sintered at low temperature having low dielectric losses and improved permeability along with the high frequency stability of permeability find applications in multilayer chip inductors.

  13. Solid State Synthesis and Thermoelectric Properties of Mg-Si-Ge System

    Renbo SONG; Yazheng LIU; Tatsuhiko AIZAWA


    Thermoelectric materials, Mg2Si1-xGex (x=0, 0.2, 0.4, 0.6, 0.8, 1), have been prepared by bulk mechanical alloying (BMA) and hot pressing (HP). The electrical conductivity, Seebeck coefficient and thermal conductivity were measured from room temperature up to about 700 K. The electrical conductivity of all the samples increases with increasing temperature, while the Seebeck coefficient and thermal conductivity decrease with increasing temperature.Mg2Si and Mg2Si0.8Ge0.2 possess negative type of conductivity, while for other compounds it is positive. At the same time, the effect of hot processing condition on thermoelectric properties was also investigated. The maximum figure of merit of Mg2Si0.6Ge0.4 was obtained with the processing parameter of BMA at 600 cycles and hot pressing at 773 K and 1 GPa for 1 h.

  14. Introductory lecture on corrosion chemistry: a focus on anodic hydrogen evolution on Al and Mg.

    Frankel, G S; Fajardo, S; Lynch, B M


    The increase in the rate of hydrogen evolution (HE) on dissolving Mg surfaces with increasing anodic current density or potential, which is sometimes called the negative difference effect, has been the topic of much discussion in recent years. A review of the very recent contributions to this subject is given in this paper. Increased catalytic activity of the corrosion product layer, either from the accumulated impurities or from the Mg oxy-hydroxide itself, is shown to have a minor influence on the anodic HE observed on dissolving Mg at high anodic current densities and potentials. Al exhibits similar characteristics during anodic polarization in concentrated HCl, although the anodic HE rate on Al is less than on Mg. Possible mechanisms for the anodic hydrogen are provided and implications in the area of intergranular corrosion and environmental cracking are discussed.

  15. Electron beam irradiated HDPE/EVA/Mg(OH)2 composites for flame-retardant electric cables

    Hui LIU; Nabil A. Noman ALKADASI; Yan ZHU; Li-fang TONG; Zheng-ping FANG; Yong-chang WANG


    The mechanical properties and flammability of high-density polyethylene (HDPE)/ethylene vinyl acetate (EVA) mixed with various amounts of magnesium hydroxide (Mg(OH)2) as the filler in composites, irra-diated with electron beam at an irradiation dose of 150 kGy, have been studied. It is found that high-energy electron beam irradiation has significant effects on the mechanical properties of the HDPE/EVA/Mg(OH)2 com-posites. The tensile strength and elastic modulus increased greater than in the unirradiated ones. Meanwhile, with increasing the content of Mg(OH)2 in the composites, the limiting oxygen index (LOI) value increased sharply. The microstructure of the caves of the unirradiated HDPE/EVA/Mg(OH)2 composites show poor interface of composites compared with the irradiated ones, as observed in SEM micrographs.

  16. Methylene blue improves hemodynamic shock but increases lipoperoxidation in severe acute pancreatitis pig model Azul de metileno melhora as condições hemodinâmicas do choque circulatório, mas aumenta a peroxidação lipídica em um modelo suino de pancreatite aguda grave

    Roberto Ferreira Meirelles Jr


    Full Text Available PURPOSE: Study hemodynamic pattern and lipoperoxidation during methylene blue (MB treatment on taurocholate - enterokinase induced acute pancreatitis (AP. METHODS: Thirty pigs were equally divided in control group; MB group; AP group; MB previous AP group; and MB after 90 min of induced AP group. MB was given iv in a bolus dose ( followed by maintenance dose (2 Hemodynamic parameters were recorded continuously during 180 min by Swan-Ganz catheter. Blood samples were taken every 60 min to determine arterial and venous nitrate, malondialdehyde (MDA and amylase. Pancreatic tissue was removed for histopathologic study. RESULTS: In AP group MBP and CO decreased over time 33% (p0.05 serum MDA when associated to AP. After induced AP, MB did not reverse MBP and CO decrease. There was no difference in serum amylase and necro-hemorrhagic findings with MB treatment. CONCLUSIONS: In this taurocholate-induced AP model MB treatment delayed hemodynamic shock and decreases serum nitrate levels but increases serum MDA levels. No volemic replacement was done and it may have been a mitigated factor to a poor tissue perfusion and impairment microcirculation. Further investigations are needed to elucidate MB treatment role during AP treatment.OBJETIVO: estudar o perfil hemodinâmico e a lipoperoxidação durante o tratamento com azul de metileno (AM de pancreatite aguda (PA induzida por taurocolato-enteroquinase. MÉTODOS: Trinta porcos foram igualmente divididos em: grupo controle, grupo AM; grupo PA; grupo AM prévio à PA; grupo AM após 90 minutos após a indução da PA. O AM foi administrado sob a forma de bolus EV ( seguido por dose de manutenção (2 Os parâmetros hemodinâmicos foram registrados continuamente durante 180 min com auxílio de cateter de Swan-Ganz. Amostras sanguíneas foram colhidas a cada 60 min para a determinação arterial e venosa de nitrato, malondialdeido (MDA and amilase. Removeu-se tecido

  17. Cytotoxicity assessment of adipose-derived mesenchymal stem cells on synthesized biodegradable Mg-Zn-Ca alloys.

    Fazel Anvari-Yazdi, Abbas; Tahermanesh, Kobra; Hadavi, Seyed Mohammad Mehdi; Talaei-Khozani, Tahereh; Razmkhah, Mahboobeh; Abed, Seyedeh Mehr; Mohtasebi, Maryam Sadat


    Magnesium (Mg)-based alloys have been extensively considered as biodegradable implant materials for orthopedic surgery. Mg and its alloys are metallic biomaterials that can degrade in the body and promote new bone formation. In this study, the corrosion behavior and cytotoxicity of Mg-Zn-Ca alloys are evaluated with adipose-derived mesenchymal stem cells (ASCs). Mg-2Zn and Mg-2Zn-xCa (x=1, 2 and 3wt.%) alloys were designated. Mg alloys were analyzed with scanning electron microscopy and potentiodynamic polarization. To understand the in-vitro biocompatibility and cytotoxicity of Mg-2Zn and Mg-2Zn-xCa alloys, ASCs were cultured for 24 and 72h in contact with 10%, 50% and 100% extraction of all alloys prepared in DMEM. Cell cytotoxicity and viability of ASCs were examined by MTT assay. Alloying elements including Zn and Ca improved the corrosion resistance of alloys were compared with pure Mg. The cytotoxicity results showed that all alloys had no significant adverse effects on cell viability in 24h. After 72h, cell viability and proliferation increased in the cells exposed to pure Mg and Mg-2Zn-1Ca extracts. The release of Mg, Zn and Ca ions in culture media had no toxic impacts on ASCs viability and proliferation. Mg-2Zn-1Ca alloy can be suggested as a good candidate to be used in biomedical applications.

  18. Tribological Analysis of Mg2Si Particulates Reinforced Powder Metallurgy Magnesium Alloy Composites under Oil Lubrication Condition

    Katsuyoshi Kondoh


    Full Text Available For the evaluation of wear behavior of Mg composites under oil lubrication conditions, powder metallurgy Mg97Y2Zn1 alloy reinforced with additive Mg2Si particles were fabricated by the repeated plastic working (RPW and hot extrusion. The RPW process was effective in refining both Mg2Si reinforcements and α-Mg grains causing the matrix hardening. When increasing the repetition number of RPW process from 200 to 600 cycles, the particle size of Mg2Si additives changed from 8 μm to 1~2 μm, and α-Mg grain size was 1 μm or less. With regard to the defensive and offensive properties of Mg alloys reinforced with Mg2Si dispersoids, the composite had superior adhesive wear resistance compared with the conventional Mg alloys because of its extremely high microhardness of 95~180 Hv by RPW process. The uniform distribution of refined Mg2Si particles was useful for improving both defensive and offensive properties against AZ31B counter disk specimens. The Mg2Si prominent dispersoids in the matrix were also effective in forming the oil grooves around them, and caused the low and stable friction coefficient. On the other hand, in the case of the composite containing coarse Mg2Si particles, severely deep scratches were given on the counter face of the AZ31B disk, and resulted in an unstable and high friction coefficient.

  19. Effect of Mn on microstructure and corrosion properties of extruded Mg-1%Zn alloy

    Zhang, Z. M.; Ma, Y.; Xi, Z. Z.; Xu, C. J.; Lv, Z. L.


    The microstructure of the extruded Mg-1Zn alloy doped with different content of manganese was analyzed by optical microscopy, scanning electron microscopy with energy dispersive X-ray spectroscopy and X-ray diffractometry. The mass-loss immersion method and electrochemical test were used to evaluate the corrosion properties. The results show that the microstructure of the extruded Mg-1%Zn-x%Mn (mass fraction, x=0.4, 0.8, 1.2) alloys consists of α-Mg and α-Mn, the grain size of α-Mg decreases with increasing Mn content. Electrochemical corrosion behavior of the alloys is similar. Mn has considerable effect on the corrosion rate, the corrosion process is exacerbated by the galvanic corrosion occurred at interface between α-Mg and α-Mn. The corrosion rate increases as the Mn content increases. Mg-1%Zn-0.4% Mn alloy exhibits the best corrosion resistance between the Mg-1%Zn-x%Mn alloys

  20. Calibration of the DH6500-MG02 and DH6500-MG03 antennas

    Nielsen, Jeppe Majlund; Pivnenko, Sergey

    frequencies. For the DH6500-MG03 horn the measurement comprises on-axis gain, and on-axis polarization at 601 frequencies. For both horns, the input reection coecient was measured at 601 frequencies. The measurement was carried out at the DTU-ESA Spherical Near-Field Antenna Test Facility in April 2013...

  1. Mechanical and Corrosive Properties of Two Magnesium Wires: Mg4Gd and Mg6Ag

    Maier, Petra; Szakács, Gabor; Wala, Marcin; Hort, Norbert

    The mechanical and corrosive properties of two Magnesium wires are studied in the field of microhardness, tension-, compression-and 3-point-bending tests, corrosion and its influence on the mechanical properties. Due to recrystallization during their complex forming processes (casting, extrusion, wire drawing), both wires show a fine grained microstructure resulting in high strength and ductility. However, the ductility is mostly evaluated by 3-point bending and compression; due to the notch effect in the clamp area, the maximum tensile strength and elongation under tension cannot be measured. Both alloys show a tensile-compressive yield asymmetry. Even RE-elements are known to reduce this asymmetry, the Mg-Gd alloy shows 100 MPa higher strength in tension than compression. The asymmetry of the Mg-Ag wire is similar. Overall the wires show very high strength and hardness, Mg6Ag slightly higher compared to Mg4Gd. Strong pitting corrosion is found and reduces strongly the tensile and bending strength.

  2. Nanometric MgFe2O4: Synthesis, characterization and its application towards supercapacitor and electrochemical uric acid sensor

    Majumder, S.; Kumar, S.; Banerjee, S.


    In this paper, we have synthesized nanocrystalline MgFe2O4 (S1) by auto-combustion assisted sol-gel method. The structure and morphology and elemental study of S1 are examined by powder X-ray diffraction (PXRD), field emission scanning electron microscopic (FESEM) and energy dispersive X-ray spectroscopic (EDS) techniques. The FESEM images reveal that the morphology of the sample is rough and average particle size is 50 nm. The PXRD study indicates that the samples are well crystalline and single phase in nature. Moreover, we have performed supercapacitor study by electrochemical galvanostatic charge-discharge (GCD) measurement, which shows pseudo capacitive behavior. S1 contains a high specific capacitance of 428.9 Fg-1 at the current density 0.0625 Ag-1 and can deliver high energy and power density of 18.01 Wh kg-1 and 21468 Wkg-1 respectively. Moreover, uric acid (UA) sensing study has also been performed by cyclic voltmetry (CV) and electrochemical impedance spectroscopy measurement (EIS) of S1. We can use nanocrystalline MgFe2O4 as supercapacitor and UA sensor applications purpose.

  3. Enhanced MgB2 Superconductivity Under High Pressure

    刘振兴; 靳常青; 游江洋; 李绍春; 朱嘉林; 禹日成; 李风英; 苏少奎


    We report on in situ high-pressure studies up to 1.0 GPa on the MgB2 superconductor which was high-pressure synthesized. The as-prepared sample is of high quality in terms of sharp superconducting transition (Tc) at 39K from the magnetic measurements. The in situ high-pressure measurements were carried out using a Be-Cu piston-cylinder-type instrument with mixed oil as the pressure transmitting medium which warrants a quasihydrostatic pressure environment at low temperature. The superconducting transitions were measured using the electrical conductance method. It is found that Tc increases by more than 1 K with pressure in the low-pressure range, before the Tc value decreases with the further increase of the pressure.

  4. Microstructural characterization of bulk MgB{sub 2}

    Wiederhold, Alex; Koblischka, Michael; Hartmann, Uwe [Institute of Experimental Physics, Saarland University, P. O. Box 151150, D-66123 Saarbruecken (Germany); Inoue, Kazuo; Muralidhar, Miryala; Murakami, Masato [Department of Material Science and Engeneering, Shibaura Institute of Technology, 3-7-5 Toyosu, Koto-ku, Tokyo 135-8548 (Japan); Berger, Kevin; Douine, Bruno [GREEN, Universite de Lorraine, Vandoeuvre-les-Nancy (France); Hauet, Thomas [Institute Jean Lamour, Universite de Lorraine, Vandoeuvre-les-Nancy (France); Noudem, Jacques [CRISMAT-CNRS, Cherbourg (France)


    A series of disk-shaped bulk MgB{sub 2} superconductors (sample diameter up to 4 cm) was prepared in order to improve the performance for superconducting super-magnets. Several samples were fabricated using a solid state reaction in pure Ar atmosphere from 750 to 950 C to obtain the highest critical current density (j{sub c}) as well as large trapped field values. Magnetization and transport measurements revealed that at the low reaction temperatures flux pinning at grain boundaries is dominant, which is decreasing on increasing temperature. At the highest reaction temperature, j{sub c} was found to increase again indicating a change of the pinning mechanism. In order to clarify this behavior the samples were characterized in detail by means of transmission electron microscopy (TEM) and transmission electron backscatter diffraction (t-EBSD).

  5. Interfacial reactions and wetting in Al-Mg sintered by powder metallurgy process

    Faisal, Heny; Darminto, Triwikantoro, Zainuri, M.


    Was conducted to analyze the effect of temperature variation on the bonding interface sintered composite Al-Mg and analyze the effect of variations of the density and hardness sinter. Research carried out by the base material powders of Al, Mg powder and solvent n-butanol. The method used in this study is a powder metallurgy, with a composition of 60% volume fraction of Al - 40% Mg. Al-Mg mixing with n-butanol for 1 hour at 500 rpm. Then the emphasis (cold comression) with a size of 1.4 cm in diameter dies and height of 2.8 cm, is pressed with a force of 20 MPa and held for 15 minutes. After the sample into pellets, then sintered at various temperatures 300 °C, 350 °C, 400 °C and 450 °C. Characterization is done by using the testing green density, sintered density, X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), vickers microhardness, and press test. XRD data analysis done by using X'Pert High Score Plus (HSP) to determine whether there is a new phase is formed. Test results show that the sintered density increasing sintering temperature, the resulting density is also increasing (shrinkage). However, at a temperature of 450 °C decreased (swelling). With the increased sinter density, interfacial bonding getting Kuta and more compact so that its hardness is also increased. From the test results of SEM / EDX, there Mg into Al in the border area. At temperatures of 300 °C, 350 °C, 400 °C, the phase formed is Al, Mg and MgO. While phase is formed at a temperature of 450 °C is aluminum magnesium (Al3Mg2), Aluminum Magnesium Zinc (AlMg2Zn).

  6. Prevention of Streptozotocin-Induced Diabetic Nephropathy by MG132: Possible Roles of Nrf2 and IκB

    Wang, Yangwei; Tan, Yi; Miao, Lining


    Our previous study showed that proteasomal inhibitor MG132 can prevent diabetic nephropathy (DN) along with upregulation of nuclear factor (erythroid-derived 2)-like 2 (Nrf2). The present study was to investigate whether MG132 can prevent DN in wild-type and Nrf2-KO mice. Type 1 diabetes was induced in wild-type and Nrf2-KO mice by multiple low doses of streptozotocin. Two weeks after streptozotocin injection, both wild-type and Nrf2-KO mice were randomly divided into four groups: control, MG132, DM, and DM/MG132. MG132 (10 μg/kg/day) or vehicle was administered intraperitoneally for 4 months. Renal function, morphology, and biochemical changes were measured after 4-month treatment with MG132. MG132 treatment suppressed proteasomal activity in the two genotypes. In wild-type mice, MG132 attenuated diabetes-induced renal dysfunction, fibrosis, inflammation, and oxidative damage along with increased Nrf2 and IκB expression. Deletion of Nrf2 gene resulted in a partial, but significant attenuation of MG132 renal protection in Nrf2-KO mice compared with wild-type mice. MG132-increased IκB expression was not different between wild-type and Nrf2-KO mice. This work indicates that MG132 inhibits diabetes-increased proteasomal activity, resulting in Nrf2 and IκB upregulation and renal protection, which could be used as a strategy to prevent diabetic nephropathy. PMID:28373900

  7. Increase in cholinergic modulation with pyridostigmine induces anti-inflammatory cell recruitment soon after acute myocardial infarction in rats.

    Rocha, Juraci Aparecida; Ribeiro, Susan Pereira; França, Cristiane Miranda; Coelho, Otávio; Alves, Gisele; Lacchini, Silvia; Kallás, Esper Georges; Irigoyen, Maria Cláudia; Consolim-Colombo, Fernanda M


    We tested the hypothesis that an increase in the anti-inflammatory cholinergic pathway, when induced by pyridostigmine (PY), may modulate subtypes of lymphocytes (CD4+, CD8+, FOXP3+) and macrophages (M1/M2) soon after myocardial infarction (MI) in rats. Wistar rats, randomly allocated to receive PY (40 mg·kg(-1)·day(-1)) in drinking water or to stay without treatment, were followed for 4 days and then were subjected to ligation of the left coronary artery. The groups-denominated as the pyridostigmine-treated infarcted (IP) and infarcted control (I) groups-were submitted to euthanasia 3 days after MI; the heart was removed for immunohistochemistry, and the peripheral blood and spleen were collected for flow cytometry analysis. Noninfarcted and untreated rats were used as controls (C Group). Echocardiographic measurements were registered on the second day after MI, and heart rate variability was measured on the third day after MI. The infarcted groups had similar MI areas, degrees of systolic dysfunction, blood pressures, and heart rates. Compared with the I Group, the IP Group showed a significant higher parasympathetic modulation and a lower sympathetic modulation, which were associated with a small, but significant, increase in diastolic function. The IP Group showed a significant increase in M2 macrophages and FOXP3(+)cells in the infarcted and peri-infarcted areas, a significantly higher frequency of circulating Treg cells (CD4(+)CD25(+)FOXP3(+)), and a less extreme decrease in conventional T cells (CD25(+)FOXP3(-)) compared with the I Group. Therefore, increasing cholinergic modulation with PY induces greater anti-inflammatory cell recruitment soon after MY in rats.


    Sikander A . K


    Full Text Available Macular edema is a frequent manifestation of diabetic retinopathy and animportant cause of visual disturbance in diabetic patients. AIM: To compare the efficacy and safety of 1mg and 4mg intravitreal triamcinolone acetonide (IVTA in the management of diabetic macular edema. SETTING: Sarojini Devi Eye Hospital, Hyderabad. MATERIAL AND METHODS: 42 eyes of 42 patients with diabetic macular edema were randomly assigned torecei ve either 1 - mg or 4 - mg dose of Intravitreal triamcinolone acetonide (IVTA. Each patient underwent a complete comprehensive eye examination at baseline andat each visit.Fundus fluorescein angiography and optical coherence angiographywas done at baseline an d at 1, 3 and 6 months.BCVA, lens status, IOP wererecorded at each follow up visit. Each patient’s BCVA was measured in snellen’s lines and converted into logarithm of minimum angle of resolution (log MAR scale for analysis. STATISTICAL ANALYSIS USED : The data were statistically evaluated using the Wilcoxon signedrank test, Mann - Whitney test and t tests wherever applicable. A p value of lessthan . 05 was considered significant. RESULTS: There was no statistically significant difference in the mean foveal thickness measurement at baseline (p=.723 or at 3 rd month (p=.878 between the sub - groups. BCVA significantly improved from baseline to subsequent visits in both the groups, but there was no statistically significant difference observed in the mean baseli ne BCVA between the two sub - groups (p=.754. There was no statistically significant difference observed in IOP between the two sub - groups at any follow up visit. CONCLUSIONS: The results of our study suggest that 1 - mg dose of IVTA is as effective as 4 - mgdo se of IVTA in improving the functional and anatomical outcome in macularedema associated with diabetic retinopathy.

  9. Comparison of initial loading doses of 5 mg and 10 mg for warfarin therapy

    Sidnei Lastória


    Full Text Available CONTEXT: The question of what is the best loading dosage of warfarin when starting anticoagulant treatment has been under discussion for ten years. We were unable to find any comparative studies of these characteristics conducted here in Brazil. OBJECTIVE: To compare the safety and efficacy of two initial warfarin dosage regimens for anticoagulant treatment. METHODS: One-hundred and ten consecutive patients of both sexes, with indications for anticoagulation because of venous or arterial thromboembolism, were analyzed prospectively. During the first 3 days of treatment, these patients were given adequate heparin to keep aPTT (activated partial thromboplastin time between 1.5 and 2.5, plus 5 mg of warfarin. From the fourth day onwards, their warfarin doses were adjusted using International Normalized Ratios (INR; target range: 2 to 3. This prospective cohort was compared with a historical series of 110 patients had been given 10 mg of warfarin on the first 2 days and 5 mg on the third day with adjustments based on INR thereafter. Outcomes analyzed were as follows: recurrence of thromboembolism, bleeding events and time taken to enter the therapeutic range. RESULTS: Efficacy, safety and length of hospital stay were similar in both samples. The sample that were given 10 mg entered the therapeutic range earlier (means: 4.5 days vs. 5.8 days, were on lower doses at discharge and had better therapeutic indicators at the first return appointment. CONCLUSIONS: The 10 mg dosage regimen took less time to attain the therapeutic range and was associated with lower warfarin doses at discharge and better INR at first out-patients follow-up visit.

  10. Humidity sensing behaviour of polyaniline/magnesium chromate (MgCrO4) composite

    T Machappa; M V N Ambika Prasad


    ‘in situ’ polymerization of polyaniline (PANI) was carried out in the presence of magnesium chromate (MgCrO4) to synthesize PANI/ceramic (MgCrO4) composite. These prepared composites were characterized by XRD, FTIR and SEM, which confirm the presence of MgCrO4 in polyaniline matrix. The temperature dependent conductivity measurement shows the thermally activated exponential behaviour of PANI /MgCrO4 composites. The decrease in electrical resistance was observed when the polymer composites were exposed to the broad range of relative humidity (ranging between 20 and 95% RH). This decrease is due to increase in surface electrical conductivity resulting from moisture absorption and due to capillary condensation of water causing change in conductivity within the sensing materials. PANI / MgCrO4 composites are found to be sensitive to low humidity ranging from 20 to 50% RH.

  11. Enhancing mechanical properties of calcite by Mg substitutions: An ab initio study

    Elstnerova, Pavlina; Friak, Martin; Hickel, Tilmann; Fabritius, Helge Otto; Lymperakis, Liverios; Petrov, Michal; Raabe, Dierk; Neugebauer, Joerg; Nikolov, Svetoslav; Zigler, Andreas; Hild, Sabine


    Arthropoda representing a majority of all known animal species are protected by an exoskeleton formed by their cuticle. The cuticle represents a hierarchically structured multifunctional bio-composite based on chitin and proteins. Some groups like Crustacea reinforce the load-bearing parts of their cuticle with calcite. As the calcite sometimes contains Mg it was speculated that Mg may have a stiffening impact on the mechanical properties of the cuticle. We present a theoretical parameter-free quantum-mechanical study of thermodynamic, structural and elastic properties of Mg-substituted calcite. Our results show that substituting Ca by Mg causes an almost linear decrease in the crystal volume with Mg concentration and of substituted crystals. As a consequence the calcite crystals become stiffer giving rise e.g. to substantially increased bulk moduli.

  12. Fabrication of Spherical AlSi10Mg Powders by Radio Frequency Plasma Spheroidization

    Wang, Linzhi; Liu, Ying; Chang, Sen


    Spherical AlSi10Mg powders were prepared by radio frequency plasma spheroidization from commercial AlSi10Mg powders. The fabrication process parameters and powder characteristics were investigated. Field emission scanning electron microscope, X-ray diffraction, laser particle size analyzer, powder rheometer, and UV/visible/infrared spectrophotometer were used for analyses and measurements of micrographs, phases, granulometric parameters, flowability, and laser absorption properties of the powders, respectively. The results show that the obtained spherical powders exhibit good sphericity, smooth surfaces, favorable dispersity, and excellent fluidity under appropriate feeding rate and flow rate of carrier gas. Further, acicular microstructures of the spherical AlSi10Mg powders are composed of α-Al, Si, and a small amount of Mg2Si phase. In addition, laser absorption values of the spherical AlSi10Mg powders increase obviously compared with raw material, and different spectra have obvious absorption peaks at a wavelength of about 826 nm.

  13. Optical Property of LiNbO3 Crystal Codoped with In, Mg and Fe


    In2O3, MgO and Fe2O3 were doped in LiNbO3 and Czochralski method was used to grow In:Mg:Fe:LiNbO3 crystals. The OH- extension transmission spectra, light scattering resistance ability, two wave coupled diffraction efficiency and response time of the crystal were measured. Codoping In and Mg in crystal will improve its light scattering resistance ability and response time. Doping In can increase the ability to replace antisite Nb and decrease the doping quantity of Mg. All these are propitious to improve the optical homogeneity of crystal. Doping Fe can improve the photorefractive sensitivity for LiNbO3 crystal. We discussed the site of In, Mg and Fe in LiNbO3 crystals and the influence of the absorption peak of OH- transmission spectra on photorefractive property for LiNbO3 crystal.

  14. Pressure-induced structural transitions in MgH2.

    Vajeeston, P; Ravindran, P; Kjekshus, A; Fjellvåg, H


    The stability of MgH2 has been studied up to 20 GPa using density-functional total-energy calculations. At ambient pressure alpha-MgH2 takes a TiO2-rutile-type structure. alpha-MgH2 is predicted to transform into gamma-MgH2 at 0.39 GPa. The calculated structural data for alpha- and gamma-MgH2 are in very good agreement with experimental values. At equilibrium the energy difference between these modifications is very small, and as a result both phases coexist in a certain volume and pressure field. Above 3.84 GPa gamma-MgH2 transforms into beta-MgH2, consistent with experimental findings. Two further transformations have been identified at still higher pressure: (i) beta- to delta-MgH2 at 6.73 GPa and (ii) delta- to epsilon-MgH2 at 10.26 GPa.

  15. Magnetocaloric phenomena in Mg-ferrite nanoparticles

    Burianova, S; Holec, P; Plocek, J [Charles University, Faculty of Science, Department of Inorganic chemistry, Prague (Czech Republic); Poltierova-Vejpravova, J, E-mail: burianovasimona@email.c, E-mail: jana@mag.mff.cuni.c


    A comparative study of magnetocaloric effect (MCE) in superparamagnetic (SPM) regime is reported in two different types of magnesium ferrite nanostructures. The samples were prepared either by microemulsion method as MgFe{sub 2}O{sub 4} nanoparticles encapsulated in amorphous SiO{sub 2}, or as matrix-less nanoparticles using hydrothermal synthesis in supercritical water conditions. The particle diameter in all prepared samples was obtained from XRD measurements and TEM analysis. All samples show a SPM behavior above the blocking temperature, T{sub B}. The entropy change, {Delta}S was finally derived from the measurements of magnetization, M(H,T) curves at defined temperature intervals. We observed, that all samples show a broad peak of {Delta}S in the temperature range that is fairly above the T{sub B}. The values of the {Delta}S also depend on the particle size, and they are of about two orders lower than those reported in the famous giant magnetocaloric materials.

  16. In vitro study of nanostructured diopside coating on Mg alloy orthopedic implants

    Razavi, Mehdi, E-mail: [Biomaterials Research Group, Department of Materials Engineering, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of); Torabinejad Dental Research Center, School of Dentistry, Isfahan University of Medical Sciences, Isfahan 81746-73461 (Iran, Islamic Republic of); School of Materials Science and Engineering, Helmerich Advanced Technology Research Center, Oklahoma State University, Tulsa, OK 74106 (United States); School of Electrical and Computer Engineering, Helmerich Advanced Technology Research Center, Oklahoma State University, Tulsa, OK 74106 (United States); Fathi, Mohammadhossein [Biomaterials Research Group, Department of Materials Engineering, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of); Dental Materials Research Center, Isfahan University of Medical Sciences, Isfahan (Iran, Islamic Republic of); Savabi, Omid [Torabinejad Dental Research Center, School of Dentistry, Isfahan University of Medical Sciences, Isfahan 81746-73461 (Iran, Islamic Republic of); Vashaee, Daryoosh [School of Electrical and Computer Engineering, Helmerich Advanced Technology Research Center, Oklahoma State University, Tulsa, OK 74106 (United States); Tayebi, Lobat, E-mail: [School of Materials Science and Engineering, Helmerich Advanced Technology Research Center, Oklahoma State University, Tulsa, OK 74106 (United States); School of Chemical Engineering, Oklahoma State University, Stillwater, OK 74078 (United States)


    The high corrosion rate of Mg alloys has hindered their application in various areas, particularly for orthopedic applications. In order to decrease the corrosion rate and to improve the bioactivity, mechanical stability and cytocompatibility of the Mg alloy, nanostructured diopside (CaMgSi{sub 2}O{sub 6}) has been coated on AZ91 Mg alloy using a combined micro arc oxidation (MAO) and electrophoretic deposition (EPD) method. The crystalline structure, the morphology and the composition of the samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). Electrochemical corrosion test, immersion test, and compression test were used to evaluate the corrosion resistance, the in vitro bioactivity and the mechanical stability of the samples, respectively. The cytocompatibility of the samples was tested by the cell viability and the cell attachment of L-929 cells. The results confirmed that the diopside coating not only slows down the corrosion rate, but also enhances the in vitro bioactivity, mechanical stability and cytocompatibility of AZ91 Mg alloy. Therefore, Mg alloy coated with nanostructured diopside offers a promising approach for biodegradable bone implants. - Highlights: • The diopside coating was applied on Mg alloy using the combined MAO and EPD methods. • The corrosion resistance of the diopside coated Mg alloy was noticeably improved. • The in vitro bioactivity of the diopside coated Mg alloy was considerably increased. • The mechanical stability of biodegradable Mg alloy was enhanced by diopside coating. • The cytocompatibility of the Mg alloy was improved employing diopside coating.

  17. Structural relationships among MgZn2 and Mg4Zn7 phases and transition structures in Mg-Zn-Y alloys

    Rosalie, Julian M.; Somekawa, Hidetoshi; Singh, Alok; Mukai, Toshiji


    Isothermal ageing of plastically deformed Mg-Zn-Y alloys resulted in precipitation along ? twin boundaries. The bulky precipitates so formed had structures similar to those recently reported for the rod-like ? precipitates, but afforded a more detailed study by high-resolution TEM due to their larger size. The core of the precipitates often had the structure of the monoclinic Mg4Zn7 phase, and had the orientation ? ; ? with either the matrix or the twin. On this Mg4Zn7 phase, the hexagonal MgZn2 phase grew in two orientations, both with ? . One of these orientations formed a known orientation relationship ? ; ? with the matrix. The part of the precipitate with the MgZn2 structure was usually in direct contact with the twin boundary. Both the Mg4Zn7 and MgZn2 phases have layered structures that can be described with similar building blocks of icosahedrally coordinated atoms. The atomic positions of zinc atoms comprise the vertices of these icosahedra and form 'thick' rhombic tiles. The orientations of these rhombuses remain unchanged across the interfaces between the two phases. Near the interface with MgZn2, transition structures formed in the Mg4Zn7 phase, with the Zn:Mg atom ratio between those of the Mg4Zn7 and MgZn2 phases. In these transition structures, the unit cell of the Mg4Zn7 phase is extended along [100] or [001] by half a unit cell length by continuation of the rhombic tiling. Structures of these extended unit cells are proposed.

  18. Superconducting Properties and Microstructure in MgB2 Bulks, Wires and Tapes

    冯勇; 阎果; 赵勇; 吴晓京; 周廉; 张平祥


    We prepared a series of MgB2 bulk samples under different temperatures, holding time and increasing rates in temperature by the solid state reaction. The thermodynamic behavior and phase formation in the Mg-B system were studied by using DTA,XRD and SEM. The results indicate that the formation of the MgB2 phase is very fast and the high increasing rate in temperature is necessary to obtain high quality MgB2. In addition, the effects of the Zr-doping in Mg1-xZrxB2 bulk samples fabricated by the solid state reaction at ambient pressure on phase compositions, microstructure and flux pinning behavior were investigated by using XRD, SQUID magnetometer, SEM and TEM. Critical current density Jc can be significantly enhanced by the Zr-doping and the best data are achieved in Mg0.9Zr0.1B2. For this sample, Jc values are remarkably improved to 1.83×106 A/cm2 in self-field and 5.51×105 A/cm2 in 1 T at 20 K. Also, high quality MgB2/Ta/Cu wires and tapes with and without Ti-doping, MgB2/Fe wires and 18 filament MgB2/NbZr/Cu tapes were fabricated by the powder-in-tube (PIT) method at ambient pressure. The phase compositions, microstructure features and flux pinning properties were studied. The results suggest that Fe is thebest metal for these sheaths. MgB2/Fe wires exhibit very high Jc at high temperatures and high fields. Jc values reach as high as 1.43×105 A/cm2 (4.2 K, 4 T) and 3.72×104 A/cm2 (15 K, 4 T).

  19. Layered Double Hydroxides with Hydrotalcite-type Structure Containing Fe3+, Al3+ and Mg2+


    Layered double hydroxides(LDHs) with hydrotalcite-type structure containing Fe3+, Al3+ and Mg2+ were prepared by means of a coprecipitation method. The products were characterized by element analysis, X-ray powder diffraction and transmission electron microscopy. It was found that even if the molar ratio of n(Fe+Al)/n(Fe+Al+Mg)>0.33, yet a pure hydrotalcite-like compound(HTlc) phase was gained when n(Fe)/n(Al+Mg+Fe)≤0.30 and n(Al)/n(Al+Mg+Fe)≤0.30; the Al(OH)3 phase appeared in the products when n(Al)/n(Al+Mg+Fe)>0.30; and an amorphous phase emerged when n(Fe)/n(Al+Mg+Fe)>0.33. These results show that there is no concentration superposition effect between Fe3+ and Al3+ on the crystalline state of the produced samples. In our previous work, the concentration superposition effect between Zn2+ and Mg2+ in the synthesis of Zn-Mg-Al-LDHs was found. For the prepared Fe-Al-Mg-LDHs samples, the value of lattice parameter a is between 0.30-0.32 nm; and the value of lattice parameter c is between 2.30-2.47 nm, the basal spacing is in the range of 0.76-0.83 nm. When the ratio of n(Fe)/n(Al) is a constant, the values of a and c increase with the increase of the Mg2+ content of the produced samples. The mean particle size and the mean crystal grain were determined by virtue of a particle-size instrument, XRD-Scherrer formula and TEM method, respectively.

  20. Thermoelectric properties of Al doped Mg{sub 2}Si material

    Kaur, Kulwinder, E-mail:; Kumar, Ranjan [Department of Physics, Center of Advanced Study in Physics, Panjab University, Chandigarh-160 014 (India); Rani, Anita [Department of Physics, Center of Advanced Study in Physics, Panjab University, Chandigarh-160 014 (India); Guru Nanak College for Girls, Sri Muktsar Sahib, Punjab (India)


    In the present paper we have calculated thermoelectric properties of Al doped Mg{sub 2}Si material (Mg{sub 2−x}Al{sub x}Si, x=0.06) using Pseudo potential plane wave method based on DFT and Semi classical Boltzmann theory. The calculations showed n-type conduction, indicating that the electrical conduction are due to electron. The electrical conductivity increasing with increasing temperature and the negative value of Seebeck Coefficient also show that the conduction is due to electron. The thermal conductivity was increased slightly by Al doping with increasing temperature due to the much larger contribution of lattice thermal conductivity over electronic thermal conductivity.

  1. Effects of Ca additions on some Mg-alloy hydrides

    Lupu, D.; Biris, A.; Indrea, E.; Bucur, R.V.


    The hydrogenation of the alloy of composition CaMg/sub 1/ /sub 8/Ni/sub 0/ /sub 5/ containing CaMg/sub 2/ and MgNi/sub 2/ shows fast activation kinetics. The Mg/sub 2/Ni phase is observed in the dehydrided samples. The three plateaus on the hydrogen desorption isotherms correspond to the most stable magnesium hydrides observed up to now in Mg-alloy ( H = 20 to 24 kcal/mol H/sub 2/). The effects of Ca additions on the hydrogen storage capacity and desorption rates of some Mg-rich alloys have been studied. 16 references, 3 figures, 1 table.

  2. Pressureless sintering of translucent MgO ceramics

    Chen Dianying [Department of Chemical, Materials and Biomolecular Engineering, Institute of Materials Science, University of Connecticut, Storrs, CT 06269 (United States); Jordan, Eric H. [Department of Mechanical Engineering, University of Connecticut, Storrs, CT 06269 (United States)], E-mail:; Gell, Maurice [Department of Chemical, Materials and Biomolecular Engineering, Institute of Materials Science, University of Connecticut, Storrs, CT 06269 (United States)


    MgO nanocrystalline powders were synthesized via a wet precipitation process. X-ray diffraction analysis of the heat-treated precursor powders shows that a crystalline MgO phase forms at {approx}500 deg. C. Translucent MgO ceramics were prepared by pressureless sintering the nanocrystalline MgO powders at 1400 deg. C for 2 h under ambient atmosphere. The as-sintered MgO ceramics have a relative density of 98.1% with an average hardness of 6.8 GPa. Scanning electron microscope characterization revealed that the translucent MgO ceramics have an average grain size of {approx}6 {mu}m.

  3. Phosphate Capacities of CaF2-MgO and CaF2-CaO-MgO Slags

    Akbari, F.; Pickles, C. A.


    Previously published sulphide capacity data and thermodynamic arguments have been employed to calculate the phosphate capacities and the phosphorus partition ratios between a molten carbon saturated iron alloy and binary CaF2-MgO slags and also ternary CaF2 -CaO-MgO slags at 1450 °C. For the CaF2-MgO binary system, a linear relationship was found between the phosphate and the sulphide capacities as follows: log ? = 1.2 log Cs + 25.2. For the ternary CaF2-CaO-MgO system at 1450 °C, the logarithm of the calculated phosphate capacities ranged from 19.47 to 20.15. With the addition of CaO, the phosphate capacities initially increased, reached a maximum and then decreased slightly. The addition of MgO to the CaF2-CaO system resulted in a decrease in the phosphate capacity. The calculated phosphorus partition ratios increased slightly with increasing mole fraction of CaO in the ternary system.

  4. The influence of metal Mg on micro-morphology and crystallinity of spherical hexagonal boron nitride

    Zhang, Ning, E-mail:; Liu, Huan; Kan, Hongmin; Wang, Xiaoyang; Long, Haibo; Zhou, Yonghui


    Highlights: • The action mechanism of Mg to the synthesis of spherical BN was explored. • The influence of Mg content on the crystallinity of h-BN powders was studied. • Even if not added any template, the spherical h-BN could be prepared. - Abstract: This search used the boric acid and borax as a source of boron, urea as a nitrogen source, Mg as metal catalyst, and thus prepared different micro-morphology and crystallinity hexagonal boron nitride powders under a flowing ammonia atmosphere at a nitriding temperature of 750 °C. The effect of Mg content on the crystallinity and micro-morphology of hexagonal boron nitride powders was studied, and the Mg action mechanism was explored. Without the added surfactant, the graphitization index (GI) was 6.87, and the diameter of the spherical h-BN was bigger. When the added Mg were 0.1 g, 0.3 g, 0.5 g and 0.7 g, the (GI) decreased to 6.04, 5.67, 4.62 and 4.84, respectively. When the Mg content was higher (0.9 g), GI value increased rapidly, and the crystallinity became bad. When the Mg content was 0.5 g, the dispersion of h-BN powders was at its optimum and refinement apparently, and the crystallinity at its highest.

  5. MG132 Inhibits Myocardial Ischemia-reperfusion Injury by Regulating Apoptotic Pathway

    Dai Cuilian; Luo Kailiang; Chen Zhangrong


    Objectives To administrated proteasome inhibitor-MG-132 prior to reperfusion in rat myocardial ischemia-reperfusion model to determine whether MG-132 could reduce myocytic apoptosis. Methods and results MG-132 (0.75 mg/kg in 2 ml DMSO) injection 5 min prior to reperfusion resulted significant reduction of myocardial reperfusion injury. This effect was accompanied by reduced polymorphonuclear neutrophils(PMN) infiltration in myocardial region surrounding the myocardial infarct, reduced apoptosis in cardiac myocytes, reduced NF-κB activation, as determined by electron microscopy, histology, immunohistochemistry, the terminal deoxynucleotidyl transferase-mediated nick endlabeling (TUNEL) method, reverse transcription-polymerase chain reaction. Functional effects of MG-132 on PMN accumulation, activation of nuclear factor kappa B(p65 mRNA and protein levels ), and apoptosis were characterized in rat myocardial tissue. MG132 time-dependently inhibited myocardial p65 mRNA expression and reduced myocardial apoptotic index (AI) after reperfusion for 2 h, 6 h and 24 h ( P<0.01 ). Moreover, MG-132 time-dependently decreased Bax protein levels, while increased Bcl-2 protein levels in ischemic and reperfused myocardium ( P<0.05 ), its effect peaked after reperfusion for 24 h. Conclusions Our results demonstrate that MG-132 reduced myocardial reperfusion injury by inhibiting myosytic apoptotic cell death and blocking activation of NF-κB, down-regulating Bax expression and up-regulating Bcl-2 expression as well as elevating Bcl-2/Bax ratio.

  6. Evolution of intermetallic phases of Al-Zn-Mg-Cu alloy during heat treatment

    FAN Xi-gang; JIANG Da-ming; MENG Qing-chang; LI Nian-kui; SUN Zhao-xia


    Al-Zn-Mg-Cu alloy is a favorable choice for aerospace applications requiring good combination of strength and toughness,which is greatly influenced by the coarse intermetallic particles. The evolution of intermetallic particles in an Al-Zn-Mg-Cu alloy during heat treatment was studied by field emission gun scanning electron microscopy (FEG-SEM) and X-ray diffractometry(XRD).The results show that there are lamellar eutectic structure (α(Al)+Mg(Zn,Al,Cu)2) and Al7Cu2Fe particles in the solidified structure.The Al7Cu2Fe particles are embedded in the eutectic structure. The content of eutectic structure decreases with the increase of holding time and disappears after 24 h. The size and morphology of Al7Cu2Fe particles exhibit no change during the heat treatment. It is found that the Al2CuMg phase is formed during the treatment at 460 ℃. A transformation process from the primary eutectic phase Mg(Zn,Al,Cu)2 to Al2CuMg is observed, and the transformation mechanism and kinetics are analyzed. The Al2CuMg constituents form in the primary Mg(Zn,Al,Cu)2 phase, and grow along the eutectic microstructure.

  7. Solution Fabrication of a Superconducting MgB2 Coated Conductor on Stainless Steel

    Wang, Yin-Bo; Chen, Li-Ping; Zhang, Chen; Wang, Yue; Guo, Zheng-Shan; Chen, Yi-Ling; Feng, Qing-Rong; Gan, Zi-Zhao


    We report the solution fabrication of a MgB2 coated conductor on a stainless steel substrate. The precursor solution of Mg(BH4)2 diethyl ether is initially synthesized by refluxing the milled mixture of NaBH4 and MgCl2 in diethyl ether. Then the Mg(BH4)2 diethyl ether is spin coated on a stainless steel substrate and annealed in Mg vapor, which yields a homogeneous MgB2 coated conductor. X-ray diffraction indicates that the grown MgB2 coated conductor is polycrystalline. It has a superconducting transition temperature of 34-37 K. The slope of the upper critical field HC2 increases with decreasing temperature, and the extrapolated value of HC2(0) reaches ~28 T. The critical current density estimated by the Bean model is JC(25K, 0T)~106 A·cm-2. These parameters indicate that the solution method is potentially able to produce MgB2 coated conductors that can satisfy application purposes.

  8. Synthesis and computational studies of Mg complexes supported by 2,2':6,2''-terpyridine ligands.

    Guard, Louise M; Palma, Julio L; Stratton, William P; Allen, Laura J; Brudvig, Gary W; Crabtree, Robert H; Batista, Victor S; Hazari, Nilay


    The reactions of the substituted 2,2':6,2''-terpyridine ligands, 4'-mesityl-2,2':6',2''-terpyridine (mesitylterpy) (1a), 4,4',4''-tri-tert-butyl-2,2':6',2''-terpyridine (tri-(t)Buterpy) (1b) and 4'-phenyl-2,2':6',2''-terpyridine (phenylterpy) (1c) with Grignard reagents were investigated. When half an equivalent of mesitylterpy or tri-(t)Buterpy were treated with MeMgBr in diethyl ether, the only products were (R-terpy)MgBr(2) (R = mesityl (5a), or tri-(t)Bu (5b)) and Me(2)Mg and a similar reaction was observed in THF. Compounds 5a and 5b were characterized by X-ray crystallography. Changing the Grignard reagent to PhMgBr also generated 5a and 5b along with Ph(2)Mg, while the reaction between MeMgCl or PhMgCl and 1a or 1b generated (R-terpy)MgCl(2) (R = mesityl (6a), or tri-(t)Bu (6b)) and either Me(2)Mg or Ph(2)Mg, respectively. The products from reactions between phenylterpy (1c) and Grignard reagents were highly insoluble and could not be fully characterized but appeared to be the same as those from reactions with 1a and 1b. In contrast to other studies using tridentate nitrogen ligands, which formed either mixed halide alkyl species or dihalide and bis(alkyl) species depending on whether the Grignard reagent was reacted with the ligand in diethyl ether or THF, the formation of mixed halide, alkyl complexes of the type (R-terpy)MgR'X (R' = Me or Ph; X = Cl or Br) or dialkyl species such as (R-terpy)MgR'(2) (R' = Me or Ph) was not observed here, regardless of the reaction conditions. DFT studies were performed to complement the experimental studies. The experimental results could not be accurately reproduced unless π-stacking effects associated with free terpyridine were included in the model. When these effects were included, the calculations were consistent with the experimental results which indicated that the formation of the terpy Mg dihalide species and R'(2)Mg (R' = Me or Ph) is thermodynamically preferred over the formation of mixed alkyl halide Mg

  9. Review: the effects of secular variation in seawater Mg/Ca on marine biocalcification

    Ries, J. B.


    Synchronized transitions in the polymorph mineralogy of the major reef-building and sediment-producing calcareous marine organisms and abiotic CaCO3 precipitates (ooids, marine cements) throughout Phanerozoic time is believed to have been caused by tectonically-induced variations in seawater molar Mg/Ca (>2="aragonite seas"; experimental seawater formulated over the range of mMg/Ca ratios (1.0 to 5.2) that occurred throughout their geologic history. Aragonite-secreting bryopsidalean algae and scleractinian corals and calcite-secreting coccolithophores exhibited higher rates of calcification and growth in the experimental seawaters that favored their skeletal mineral. These results support the assertion that seawater Mg/Ca played an important role in determining which hypercalcifying marine organisms were the major reef-builders and sediment-producers throughout Earth history. The observation that primary production increased along with calcification in mineralogically-favorable seawater is consistent with the hypothesis that calcification promotes photosynthesis within autotrophs through the liberation of CO2. The Mg/Ca ratio of calcite secreted by the coccolithophores, coralline algae and reef-dwelling animals (crustacea, urchins, calcareous tube worms) declined with reductions in seawater Mg/Ca. Calcifying microbial biofilms varied their mineral polymorph with seawater Mg/Ca (mMg/Ca2=arag+high Mg calc), suggesting a nearly abiotic mode of calcification. These results indicate that biomineralogical control can be partially overridden by ambient seawater Mg/Ca and suggests that modern high Mg calcite organisms probably secreted low Mg calcite in calcite seas of the past. Notably, Mg fractionation in autotrophic organisms was more strongly influenced by changes in seawater Mg/Ca, a probable consequence of them inducing a less controlled mode of calcification simply through the removal of CO2 via photosynthesis. This body of work also has implications for thermal

  10. Phase equilibria in the Mg-rich corner of the Mg-Zn-La system at 350℃

    LI Hongxiao; REN Yuping; HUANG Mingli; CHEN Qin; HAO Shiming


    The phase equilibria in the Mg-rich corner of the Mg-Zn-La system at 350℃ have been investigated by scanning electron microscopy, X-ray diffraction, and electron probe microanalysis. It has been shown that the linear compound (Mg,Zn)17La2 existed in the Mg-Zn-La system at 350℃. The linear compound (so-called T phase) was with the C-centred orthorhombic crystal structure induced by the solution of significant quantities of the third element. The three-phase region α(Mg) + MgZn(La) + T and the two-phase region composed of the α(Mg) and the linear-compound T phase existed in the Mg-rich corner of the Mg-Zn-La system at 350℃.

  11. Synthesis kinetics of Mg_2Sn in Mg-Sn powder mixture using non-isothermal differential scanning calorimetry

    WU Yu-feng; DU Wen-bo; ZUO Tie-yong


    The non-isothermal heating process of Mg-Sn powder mixture was studied by differential scanning calorimetry(DSC) technique and the synthesis kinetics of Mg_2Sn was evaluated by the model-free and model-fitting methods. The activation energy and conversion function of Mg_2Sn synthesis reaction are calculated to be 281.7 kJ/mol and g(α)=[-ln(1-α)]~(1/4), respectively. The reaction mechanism of 2Mg+Sn→Mg_2Sn under non-isothermal condition is regarded as "nucleation and growth". During the non-isothermal heating process, the phase transformation occurred in the Mg-Sn powder mixture was analyzed by XRD and the microstructure evolution of Mg_2Sn was observed by optical microscopy, which is in good agreement with the reaction mechanism of 2Mg+Sn→Mg_2Sn deduced from the kinetic evaluation.

  12. Investigation of the effect of Mg doping for improvements of optical and electrical properties

    Caglar, Mujdat, E-mail:; Caglar, Yasemin; Ilican, Saliha


    Sol–gel spin coating method was used for the deposition of nanostructured undoped and Mg doped ZnO films. The effects of magnesium incorporation on the crystalline structure were investigated by XRD measurements and the structural deterioration was observed in the crystalline quality of the films with respect to increasing in Mg doping. All the samples exhibited a wurtzite structure. From the scanning electron microscopy (SEM) images obtained to investigate the surface morphology it was detected that an increase in Mg doping caused an improvement on the surface roughness and a reduction in the number of voids on the surface. To evaluate the absorption edges of the produced samples depending on the Mg, different methods were used and according to the obtained results, a shifting towards to high energies for the optical band gap was observed in each method. By using the single oscillator model, developed by DiDomenico and Wemple, the refractive index dispersion of the films was analyzed. E{sub o} and E{sub d} values of the 5% Mg doped film were found to be 5.76 eV and 11.80 eV, respectively. Within the scope of electrical properties, from Hall effect measurements, it was determined that all the films exhibited n-type behavior and the carrier concentration increased from 1.49×10{sup 16} to 1.20×10{sup 17} cm{sup −3} with increasing Mg doping.

  13. Thermoluminescence studies of γ-irradiated ZnO:Mg{sup 2+} nanoparticles

    Pushpa, N. [Department of Physics, Bangalore University, Bangalore 560 056 (India); Kokila, M.K., E-mail: [Department of Physics, Bangalore University, Bangalore 560 056 (India); Nagabhushana, K.R. [Department of Physics - S & H, PES University, Bangalore 560 085 (India)


    Pure and Mg{sup 2+} doped ZnO nanoparticles are synthesized by solution combustion method. X-ray diffraction studies of the samples confirm hexagonal phase. Crystallite size is calculated using Scherer formula and found to be ∼30 nm for undoped ZnO and 34–38 nm for Mg{sup 2+} doped ZnO. A broad PL emission in the range 400–600 nm with peaks at 400, 450, 468, 483, 492, 517, 553 nm are observed in both pure and Mg{sup 2+} doped nanoparticles. Near band edge emission of ZnO is observed at 400 nm. The broad band emissions are due to surface defects. PL emission intensity is found to increase with Mg{sup 2+} concentration up to 1.5 mol% and then decreases due to concentration quenching. Samples are irradiated with γ-rays in a dose range 0.05–8 kGy. Gamma irradiation doesn’t affect PL properties. Undoped samples exhibit unstructured low intense TL glow with peak at 720 K. Whereas Mg{sup 2+} doped samples exhibit well structured TL glow curves with peak at ∼618 K. TL glow peak intensity of Mg{sup 2+} doped samples increases with Mg{sup 2+} concentration up to 2 mol%, thereafter decreases. TL curves of Mg{sup 2+} (2 mol%) doped ZnO exhibit two glows, a high intense peak at 618 K and a weak one with peak at ∼485 K. TL intensity of Mg{sup 2+} (2 mol%) doped ZnO samples increases with gamma dose up to 1 kGy and then decreases. Kinetic parameters of TL glows are calculated by deconvolution technique. Activation energy and frequency factor are found to be 1.5 eV and 3.38 × 10{sup 11} s{sup −1} respectively.

  14. Performance of Mg-14Li-1Al-0.1Ce as anode for Mg-air battery

    Ma, Yibin; Li, Deyu [School of Chemical Engineering and Technology, Harbin Institute of Technology, West Street No. 92, Harbin 150001 (China); Li, Ning [School of Chemical Engineering and Technology, Harbin Institute of Technology, West Street No. 92, Harbin 150001 (China); Key Laboratory of Superlight Materials and Surface Technology, Ministry of Education, Harbin Engineering University, Harbin 150001 (China); Zhang, Milin; Huang, Xiaomei [Key Laboratory of Superlight Materials and Surface Technology, Ministry of Education, Harbin Engineering University, Harbin 150001 (China)


    In this research, a new Mg-air battery based on Mg-14Li-1Al-0.1Ce was prepared and the battery performance was investigated by constant current discharge test. The corrosion behavior of Mg, AZ31 and Mg-Li-Al-Ce were studied by self-corrosion rate measurement and potentiodynamic polarization measurement. The characteristics of Mg-Li-Al-Ce after discharge were investigated by electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM) and X-ray diffraction (XRD). The results show that Mg-Li-Al-Ce is more active than Mg and AZ31. The self-corrosion rate is found to be in the order: Mg-Li-Al-Ce < Mg < AZ31. It has been observed that the Mg-air battery based on Mg-Li-Al-Ce offers higher operating voltage, anodic efficiency and capacity than those with Mg and AZ31. SEM and EIS results show that the discharge product of Mg-Li-Al-Ce is loosely adhered to the alloy surface, and thus Mg-Li-Al-Ce could keep high discharge activity during discharge. (author)

  15. Band gap engineering and enhanced photoluminescence of Mg doped ZnO nanoparticles synthesized by wet chemical route

    Arshad, Mohd; Meenhaz Ansari, Mohd [Department of Applied Physics, Aligarh Muslim University, Aligarh (India); Ahmed, Arham S. [Department of Physics, Aligarh Muslim University, Aligarh (India); Tripathi, Pushpendra [Department of Applied Physics, Aligarh Muslim University, Aligarh (India); Ashraf, S.S.Z. [Department of Physics, Aligarh Muslim University, Aligarh (India); Naqvi, A.H. [Department of Applied Physics, Aligarh Muslim University, Aligarh (India); Azam, Ameer, E-mail: [Department of Applied Physics, Aligarh Muslim University, Aligarh (India)


    In the present investigations Mg doped ZnO nanoparticles were synthesized using sol–gel method. Mg doping in nanoparticles was found to be a good method for tuning of band gap and photoluminescence of ZnO nanoparticles. Simultaneously, Mg doping also inhibited the growth of particle size and it decreased from 36.1 to 13.5 nm with the increase in doping concentration from 0% to 12%. Optical band gap was found to increase from 3.23 to 3.47 eV and photoluminescence studies revealed that visible PL emission was enhanced with doping concentration. - Highlights: • Significant decrease in particle size with Mg doping. • Increase in band gap with Mg doping. • Enhanced luminescence as a result of Mg doping.

  16. Investigation of lauric acid dopant as a novel carbon source in MgB 2 wire

    Lee, C. M.; Lee, S. M.; Park, G. C.; Joo, J.; Lim, J. H.; Kang, W. N.; Yi, J. H.; Jun, B.-H.; Kim, C.-J.


    We fabricated lauric acid (LA) doped MgB2 wires and investigated the effects of the LA doping. For the fabrication of the LA-doped MgB2 wires, B powder was mixed with LA at 0-5 wt.% of the total amount of MgB2 using an organic solvent, dried, and then the LA-treated B and Mg powders were mixed stoichiometrically. The powder mixture was loaded into an Fe tube and the assemblage was drawn and sintered at 900 °C for 3 h under an argon atmosphere. We observed that the LA doping induced the substitution of C for the B sites in MgB2 and that the actual content of C increased monotonically with increasing LA doping level. The LA-doped MgB2 wires exhibited a lower critical temperature (Tc), but better critical current density (Jc) behavior in a high magnetic field: the 5 wt.% LA-doped sample had a Jc value of 5.32 × 103 A/cm2, which was 2.17 times higher than that of the pristine sample (2.45 × 103 A/cm2) at 5 K and 6 T, suggesting that LA is an effective C dopant in MgB2 for enhancing the high-field Jc performance.

  17. Influence of MgO-type Expansive Agent Hydration Behaviors on Expansive Properties of Concrete

    LU Xiaolin; GENG Fei; ZHANG Hongbo; CHEN Xiong


    The hydration behaviors and expansive properties of MgO-type expansive agent curing at different temperatures and environment were investigated. When the curing temperatures changed from 25℃ to 50 ℃, the conductivities of MgO samples increased from 40 to 80 μ s/cm,and the hydrations of MgO were quickened up obviously. Through SEM observation, the hydration product of MgO cured at 50 ℃ for 28 day was about 2-3 μ m in length. The expansion of pastes with 5% of the MgO-type expansive agent was from 0.36% to 1.01% when the curing temperature changed from 25℃ to 50 ℃. When 8% of the MgO-type expansive agent was added, the early shrinkage of concrete was reduced. The expansion ratio increased with the curing temperature, and the expansive cracking of concrete with MgO-type expansive agent might be decreased by blending fly ash.

  18. Development of high strength Sn-Mg solder alloys with reasonable ductility

    Alam, Md Ershadul; Gupta, Manoj


    This study discussed the development of a series of new lead-free Sn-Mg solders by incorporating varying amounts of Mg (0.8, 1.5 and 2.5 wt. %) into pure Sn using disintegrated melt deposition technique followed by room temperature extrusion. All extruded Sn and Sn-Mg solder samples were characterized. Microstructural characterization studies revealed equiaxed grain morphology, minimal porosity and relatively uniform distribution of secondary phase. Better coefficient of thermal expansion was observed for Sn-2.5Mg sample when compared to conventional Sn-37Pb solder. Melting temperature of Sn-1.5Mg was found to be 212°C which is much lower than the conventional Sn-Ag-Cu or Sn-Cu (227°C) solders. Microhardness was increased with increasing amount of Mg in pure Sn. Room temperature tensile test results revealed that newly developed Sn-Mg solders exhibit enhanced strengths (0.2% yield strength and ultimate tensile strength) with comparable (if not better) ductility when compared to other commercially available and widely used Sn-based solder alloys.

  19. TEM Nanostructural Study of Al-6Si-3Cu-Mg Melt-Spun Ribbons

    Ismeli Alfonso López


    Full Text Available Three quaternary Al-6Si-3Cu-xMg (x = 0.59, 3.80, and 6.78 wt.% alloys were produced by melt-spun and characterized using X-ray diffractometry (XRD, transmission electron microscopy (TEM, and microhardness techniques. Obtained second phases were Al2Cu( for the alloy with 0.59% Mg and Al5Cu2Mg8Si6 (Q for the alloys with 3.80 and 6.78% Mg. These phases are present as 30–50 nm or as 5–10 nm nanoparticles. Alloying elements content in solid solution increased, mainly for Si and Mg. The high alloying elements content in solid solution and the small -Al cell size for melt-spun alloys leads to microhardness values about 2 times higher than those of ingot counterparts. The microhardness increase for melt-spun alloys with 3.80 and 6.78% Mg depends on Mg content in solid solution.

  20. Study of reactions of activated Mg-based powders in heated steam

    Huang, Hai-tao; Zou, Mei-shuai; Guo, Xiao-yan; Yang, Rong-jie; Li, Yun-kai


    Activated Mg-based powders are prepared by high-energy milling and characterised with XRD, SEM, TG and BET techniques. This study focus on reactions of Mg-based powders with flowing steam that is heated at 500, 600, and 700 °C in a transparent pipe furnace. Morphologies and phases of solid reaction products are analysed by SEM, XRD, and residual metal content, and ignition delay times are measured. Experimental results show that all Mg-based powders oxidise at 500 °C and ignite at 600 °C. At 700 °C, all samples burn completely to form magnesium oxide (MgO) within 5 min. Residual metal contents and ignition delay times of all samples decrease with increasing temperature, and ignition delay times of activated Mg-based materials containing cobalto-cobaltic oxide (Co3O4) are only 22 s at 700 °C. Milled Mg powders are more reactive in heated steam than unmilled Mg powders, and the addition of Co3O4 further increases magnesium reactivity in heated steam.

  1. Understanding and Enhancing Hydrogen Diffusion in MgH2 and NaMgH3

    Sholl, David; Hao, Shiqiang


    The transport properties of hydrogen in metal hydrides are crucial to the kinetics of H2 storage in these materials. We use first-principles calculations to identify the defects that are relevant for H transport in MgH2 and NaMgH3. In both materials, the physically relevant defects are charged and H diffusion is dominated by mobility of negatively charged interstitial H. Interestingly, the diffusion of these species occurs via concerted mechanisms with low energy barriers. To improve the charged interstitial H diffusivity, a series of transition-metal additives are screened to lower the formation energy of mobile defects. Our results provide a practical way to examine and alter H diffusion in light metal hydrides.

  2. Room-temperature perpendicular magnetic anisotropy of MgO/Fe/MgO ultrathin films

    Kozioł-Rachwał, A.; Ślęzak, T.; Przewoźnik, J. [Faculty of Physics and Applied Computer Science, AGH University of Science and Technology, al. Mickiewicza 30, 30-059 Kraków (Poland); Skowroński, W.; Stobiecki, T. [Department of Electronics, AGH University of Science and Technology, al. Mickiewicza 30, 30-059 Kraków (Poland); Wilgocka-Ślęzak, D. [Jerzy Haber Institute of Catalysis and Surface Chemistry, Polish Academy of Sciences, ul. Niezapominajek 8, 30-239 Kraków (Poland); Qin, Q. H.; Dijken, S. van [NanoSpin, Department of Applied Physics, Aalto University School of Science, P.O. Box 15100, FI-00076 Aalto (Finland); Korecki, J. [Faculty of Physics and Applied Computer Science, AGH University of Science and Technology, al. Mickiewicza 30, 30-059 Kraków (Poland); Jerzy Haber Institute of Catalysis and Surface Chemistry, Polish Academy of Sciences, ul. Niezapominajek 8, 30-239 Kraków (Poland)


    We used the anomalous Hall effect to study the magnetic properties of MgO/Fe(t)/MgO(001) structures in which the Fe thickness t ranged from 4 Å to 14 Å. For the iron deposited at 140 K, we obtained perpendicular magnetization at room temperature below the critical thickness of t{sub c} = (9 ± 1) Å. In the vicinity of t{sub c}, the easy magnetization axis switched from an out-of-plane orientation to an in-plane orientation, and the observed spin-reorientation transition was considered in terms of the competition among different anisotropies. The perpendicular magnetization direction was attributed to magnetoelastic anisotropy. Finally, the temperature-dependent spin-reorientation transition was analyzed for Fe thicknesses close to t{sub c}.

  3. Mg ion implantation on SLA-treated titanium surface and its effects on the behavior of mesenchymal stem cell

    Kim, Beom-Su; Kim, Jin Seong [Wonkwang Bone Regeneration Research Institute, Wonkwang University, Iksan 570-749 (Korea, Republic of); Bonecell Biotech Inc., 77, Dunsan-ro, Seo-gu, Daejeon 302-830 (Korea, Republic of); Park, Young Min [DIO Corporation, 66, Centum seo-ro, Haeundae-gu, Busan (Korea, Republic of); Choi, Bo-Young [Department of Oral and maxillofacial Surgery, Wonkwang University Daejeon Dental Hospital, Daejeon 302-830 (Korea, Republic of); Lee, Jun, E-mail: [Wonkwang Bone Regeneration Research Institute, Wonkwang University, Iksan 570-749 (Korea, Republic of); Bonecell Biotech Inc., 77, Dunsan-ro, Seo-gu, Daejeon 302-830 (Korea, Republic of)


    Magnesium (Mg) is one of the most important ions associated with bone osseointegration. The aim of this study was to evaluate the cellular effects of Mg implantation in titanium (Ti) surfaces treated with sand blast using large grit and acid etching (SLA). Mg ions were implanted into the surface via vacuum arc source ion implantation. The surface morphology, chemical properties, and the amount of Mg ion release were evaluated by scanning electron microscopy (SEM), Auger electron spectroscopy (AES), Rutherford backscattering spectroscopy (RBS), and inductively coupled plasma-optical emission spectrometer (ICP-OES). Human mesenchymal stem cells (hMSCs) were used to evaluate cellular parameters such as proliferation, cytotoxicity, and adhesion morphology by MTS assay, live/dead assay, and SEM. Furthermore, osteoblast differentiation was determined on the basis of alkaline phosphatase (ALP) activity and the degree of calcium accumulation. In the Mg ion-implanted disk, 2.3 × 10{sup 16} ions/cm{sup 2} was retained. However, after Mg ion implantation, the surface morphology did not change. Implanted Mg ions were rapidly released during the first 7 days in vitro. The MTS assay, live/dead assay, and SEM demonstrated increased cell attachment and growth on the Mg ion-implanted surface. In particular, Mg ion implantation increased the initial cell adhesion, and in an osteoblast differentiation assay, ALP activity and calcium accumulation. These findings suggest that Mg ion implantation using the plasma source ion implantation (PSII) technique may be useful for SLA-treated Ti dental implants to improve their osseointegration capacity. - Highlights: ► Mg ion was coated onto surface of SLA treated titanium via vacuum arc source ion implantation method. ► The morphological characteristics did not change after Mg ion implantation. ► Mg ion implanted SLA Ti is highly cytocompatible. ► Initial cell adhesion of MSCs is improved by Mg ion implantation. ► Mg ion implantation

  4. Foaming behaviour of Al-Si-Cu-Mg alloys

    Kim, A. [Kongju National University (Korea). Dept. of Mechanical Engineering; Cho, S.S. [Chungnam National University, Daejeon (Korea). School of Materials Engineering; Lee, H.J. [Hanbat National University, Daejeon (Korea). Dept. of Building Service Engineering


    The powder metallurgical route was utilised to obtain the Al-5Si-4Cu-4Mg (alloy 544) and Al-3Si-2Cu-2Mg (alloy 322) foams. Various steps such as centrifugal atomisation, mixing alloy powder and foaming agent (1 wt-%TiH{sub 2}), cold compaction of mixture, hot extrusion and foaming in a preheated furnace were performed. Foaming behaviour of the alloys was investigated by digital microscopy, image analysis, scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) mapping in this study. It was found that alloy 544 takes a shorter period of time to initiate pore nucleation than alloy 322. Alloy 544 had a higher pore growth rate than alloy 322 at the same pre-set furnace temperature. In both alloys, crack-like pore nucleation occurred between aluminium alloy powders elongated in a direction parallel to the extrusion direction. Both alloys showed the same foaming sequence of crack-like pore nucleation, spherical pore growth, coalescence of neighbouring pores and collapse of pores adjacent to the free surface of specimen. The time required to start pore nucleation decreased with the increase of foaming temperature. The cell walls of both alloys consisted of {alpha}-Al phase and eutectic phase. (author)


    O. D. Ostroumova


    Full Text Available Aim. To study influence of the fixed bisoprolol (BIS + hydrochlorothiazide (HCT combination on blood pressure (BP level and a blood flow in middle cerebral artery in patients with a arterial hypertension (HT, 1 degree.Material and methods. 18 patients with HT 1 degree (7 men, 11 women; age 50,1±5,7 y.o. were included in the non-comparative open study. All patients received a combination of selective beta1-adrenoblocker (BIS 2.5-5 mg and diuretic (HCT 6,25 mg. Initially and in 12 weeks of the treatment all patients had a standard clinical examination, ambulatory BP monitoring, ultrasonography of mesencephalic arteries for evaluation of the cerebrovascular blood flow reactivity.Results. The target BP level (<140/90 mm Hg in 12 weeks of the treatment (12 patients received BIS 5 mg/HCT 6,25 mg, 6 patients - BIS 2,5 mg/HCT 6,25 mg was reached in 100% of patients. Besides, significant increase in cerebral blood flow reactivity was found in tests with hyper- and hypoventilation.Conclusion. The fixed BIS/HCT combination has high antihypertensive and vasoprotective efficacy.

  6. In vitro and in vivo corrosion, mechanical properties and biocompatibility evaluation of MgF2-coated Mg-Zn-Zr alloy as cancellous screws.

    Li, Zhen; Shizhao, Sun; Chen, Minfang; Fahlman, Bradley Dean; Debao Liu; Bi, Hongwei


    Magnesium (Mg) and its alloys as biodegradable materials have received much attention in the orthopedics applications; however, the corrosion behavior of these metals in vivo remains challenging. In this work, a dense and nanoscale magnesium fluoride (MgF2) coating was deposited on the surface of Mg-Zn-Zr (MZZ) alloy cancellous screw. The MZZ cancellous screw with MgF2 coating maintained an integrated shape and high yield tensile stress after 30days immersion in SBF, comparing with the bare screw. Hydrogen releasing rate of the MZZ samples was suppressed at a lower level at the initial stage, which is in favour of the adhesion of the cells. And in vivo experiments indicated that MgF2-coated MZZ screws presented advantages in cytocompatibility, osteoconductivity and osteogenesis of cancellous bone in rabbits. Corrosion rate in vivo perfusion environment increased very slowly with time in long-term study, which was an opposite trend in vitro static immersion test. Moreover, maximum corrosion rate (CRmax), a critical calculation method of corrosion rate was introduced to predict fracture regions of the sample. The MZZ alloy with MgF2 coating possesses a great potential for clinical applications for internal fracture fixation repair. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. First-principles calculations of perpendicular magnetic anisotropy in Fe1-x Co x /MgO(001) thin films.

    Cai, Guanzhi; Wu, Zhiming; Guo, Fei; Wu, Yaping; Li, Heng; Liu, Qianwen; Fu, Mingming; Chen, Ting; Kang, Junyong


    The perpendicular magnetic anisotropy (PMA) of Fe1-x Co x thin films on MgO(001) was investigated via first-principles density-functional calculations. Four different configurations were considered based on their ground states: Fe/MgO, Fe12Co4/MgO, Fe10Co6/MgO, and Fe8Co8/MgO. As the Co composition increases, the amplitude of PMA increases first from Fe/MgO to Fe12Co4/MgO, and then decreases in Fe10Co6/MgO; finally, the magnetic anisotropy becomes horizontal in Fe8Co8/MgO. Analysis based on the second-order perturbation of the spin-orbit interaction was carried out to illustrate the contributions from Fe and Co atoms to PMA, and the differential charge density was calculated to give an intuitive comparison of 3d orbital occupancy. The enhanced PMA in Fe12Co4/MgO is ascribed to the optimized combination of occupied and unoccupied 3d states around the Fermi energy from both interface Fe and Co atoms, while the weaker PMA in Fe10Co6/MgO is mainly attributed to the modulation of the interface Co-d xy orbital around the Fermi energy. By adjusting the Co composition in Fe1-x Co x , the density of states of transitional metal atoms will be modulated to optimize PMA for future high-density memory application.

  8. High speed twin roll casting of Al-3Si-0.6Mg strip

    Haga, T.; Ikawa, M; H.Watari; S. Kumai


    Purpose: Purpose of this paper is to clear the possibility of high speed roll casting of thin strip of Al-3%Si-0.6%Mg alloy. Investigation of the mechanical properties of the roll cast Al-3%Si-0.6%Mg strip was purpose, too.Design/methodology/approach: Method used in the present study was high speed twin roll caster and low temperature casting. These methods were used to realize rapid solidification, and increase of casting speed.Findings: Findings are that Al-3%Si-0.6%Mg was could be cast at ...

  9. Effect of Mg Addition on the Ferrite Grain Boundaries Misorientation in HAZ of Low Carbon Steels

    Kai Zhu; Zhenguo Yang


    The relation between the Mg treatment and ferrite grain boundaries misorientation was investigated. The orientation imaging; microscopy technique based on electron backscattered diffraction technique (EBSD) was used in this work. It was found that the addition of 0.005 wt% Mg to the steel could evidently increase the ratio of acicular ferrite crystals appearing at large angles boundaries to each other, which was attributed to the nucleation of the second-phase particles by the Mg treatment. The EBSD techniques provide a powerful method to characterize and quantify the ferrite grain boundaries misorientation, in order to relate it to toughness.

  10. Conducting grain boundaries enhancing thermoelectric performance in doped Mg2Si

    Muthiah, Saravanan; Pulikkotil, Jiji; Srivastava, A. K.; Kumar, Ashok; Pathak, B. D.; Dhar, Ajay; Budhani, R. C.


    The thermoelectric properties of Pb doped Mg2Si, synthesized using reactive sintering employing spark plasma sintering, are investigated and are compared with other dopants reported in literature. While a moderate decrease in Seebeck coefficient and thermal conductivity is observed for 2 at. % of Pb doping in Mg2Si, a substantial enhancement in the material's thermoelectric figure-of-merit is observed, which is due to an enormous increase in its electrical conductivity. A brick-layer model is proposed to explain these results, wherein the inter-granular electronic conductivity is facilitated by Pb (or Mg2Pb) phases at grain boundaries, which is supported by microstructural evidences.

  11. Design of an age hardening Mg-Li alloy and its aging behavior

    Hao Zhong; Peiying Liu; Tietao Zhou; Huanxi Li


    An effort was made to design an age hardening Mg-Li alloy based on the phase diagrams calculated by means of "THERMO-CALC"-a thermodynamic software. Experiments were carried out to verify the calculated results by melting the alloy and examining its structure and aging behavior. The results show that the alloy possesses a structure constituent as expected, besides,the alloy has apparent aging behavior and over aging happens even at lower temperature. Metastable (Mg, Li, Al, Zn) phase has been identified when the hardness reaches the aging peak. With the increase of the aging time, (Mg, Li, Al, Zn) phase transforms to stable α phase and over aging happens.

  12. Surface modification of an Mg-1Ca alloy to slow down its biocorrosion by chitosan.

    Gu, X N; Zheng, Y F; Lan, Q X; Cheng, Y; Zhang, Z X; Xi, T F; Zhang, D Y


    The surface morphologies before and after immersion corrosion test of various chitosan-coated Mg-1Ca alloy samples were studied to investigate the effect of chitosan dip coating on the slowdown of biocorrosion. It showed that the corrosion resistance of the Mg-Ca alloy increased after coating with chitosan, and depended on both the chitosan molecular weight and layer numbers of coating. The Mg-Ca alloy coated by chitosan with a molecular weight of 2.7 x 10(5) for six layers has smooth and intact surface morphology, and exhibits the highest corrosion resistance in a simulated body fluid.

  13. Surface modification of an Mg-1Ca alloy to slow down its biocorrosion by chitosan

    Gu, X N; Zheng, Y F; Lan, Q X [State Key Laboratory for Turbulence and Complex System and College of Engineering, Peking University, Beijing 100871 (China); Cheng, Y; Xi, T F [Center for Biomedical Materials and Tissue Engineering, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871 (China); Zhang, Z X [Biomedical Engineering Research Center, Research Institute of Peking University in Shenzhen, Shenzhen 518057 (China); Zhang, D Y, E-mail:, E-mail:, E-mail:, E-mail:, E-mail:, E-mail:, E-mail: [Lifetech Scientific (Shenzhen) Co. Ltd, Hi-Tech Park, Shenzhen 518000 (China)


    The surface morphologies before and after immersion corrosion test of various chitosan-coated Mg-1Ca alloy samples were studied to investigate the effect of chitosan dip coating on the slowdown of biocorrosion. It showed that the corrosion resistance of the Mg-Ca alloy increased after coating with chitosan, and depended on both the chitosan molecular weight and layer numbers of coating. The Mg-Ca alloy coated by chitosan with a molecular weight of 2.7 x 10{sup 5} for six layers has smooth and intact surface morphology, and exhibits the highest corrosion resistance in a simulated body fluid.

  14. Effect of Ca addition on the corrosion behavior of Mg-Al-Mn alloy

    Yang, Jiang; Peng, Jian; Nyberg, Eric A.; Pan, Fu-sheng


    The microstructures and corrosion resistance of magnesium-5 wt% aluminum-0.3 wt% manganese alloys (Mg-Al-Mn) with different Ca additions (0.2-4 wt%) were investigated. Results showed that with increasing Ca addition, the grain of the alloys became more refined, whereas the corrosion resistant ability of the alloys initially increased and then decreased. The alloy with 2 wt% Ca addition exhibited the best corrosion resistance, attributed to the effect of the oxide film and (Mg,Al)2Ca phases which were discontinuously distributed on the grain boundaries. These phases acted as micro-victims, they preferentially corroded to protect the α-Mg matrix. The oxide film formed on the alloy surface can hinder the solution further to protect the α-Mg matrix.




    In this paper, we report on the structural properties and superconductivity of Mg(B1-xCx)2 compounds. Powder X-ray diffraction results indicate that the samples crystallize in a hexagonal AlB2-type structure. Due to the chemical activity of Mg powders, a small amount of MgO impurity phase is detected by X-ray diffraction. The lattice parameters decrease slightly with the increasing carbon content. Magnetization measurements indicate that the non-stoichiometry of MgB2 has no influence on the superconducting transition temperature and the transition temperature width. The addition of carbon results in a decrease of Tc and an increase of the superconducting transition width, implying the loss of superconductivity.

  16. Hydrogen insertion effects on the electronic structure of equiatomic MgNi traced by ab initio calculations

    Matar, Samir F. [CNRS, ICMCB, UPR 9048, Pessac (France); Bordeaux Univ., Pessac (France). ICMCB, UPR 9048; Al Alam, Adel F.; Ouaini, Naim [Univ. Saint Esprit de Kaslik (USEK), Jounieh (Lebanon). URA GREVE, CSR-USEK


    For equiatomic MgNi which can be hydrogenated up to the composition MgNiH{sub 1.6} at an absorption/desorption temperature of 200 C, the effects of hydrogen absorption are approached with the model structures MgNiH, MgNiH{sub 2} and MgNiH{sub 3}. From full geometry optimization and calculated cohesive energies obtained within DFT, the MgNiH{sub 2} composition close to the experimental limit is identified as most stable. Charge density analysis shows an increasingly covalent character of hydrogen: MgNiH(H{sup -0.67}) {yields} MgNiH{sub 2}(H{sup -0.63}) {yields} MgNiH{sub 3}(H{sup -0.55}). While Mg-Ni bonding prevails in MgNi and hydrogenated model phases, extra itinerant low-energy Ni states appear when hydrogen is introduced signaling Ni-H bonding which prevails over Mg-H as evidenced from total energy calculations and chemical bonding analyses. (orig.)

  17. Decaying shock studies of phase transitions in MgOSiO2 systems: implications for the Super-Earths interiors

    Bolis, R M; Vinci, T; Ravasio, A; Bambrink, E; Guarguaglini, M; Koenig, M; Musella, R; Remus, F; Bouchet, J; Ozaki, N; Miyanishi, K; Sekine, T; Sakawa, Y; Sano, T; Kodama, R; Guyot, F; Benuzzi-Mounaix, A


    We report an experimental study of the phase diagrams of periclase (MgO), enstatite (MgSiO3) and forsterite (Mg2SiO4) at high pressures. We investigated with laser driven decaying shocks the pressure/temperature curves of MgO, MgSiO3 and Mg2SiO4 between 0.2-1.2 TPa, 0.12-0.5 TPa and 0.2-0.85 TPa respectively. A melting signature has been observed in MgO at 0.47 TPa and 9860 K, while no phase changes were observed neither in MgSiO3 nor in Mg2SiO4. An increasing of reflectivity of MgO, MgSiO3 and Mg2SiO4 liquids have been detected at 0.55 TPa -12 760 K, 0.15 TPa - 7540 K, 0.2 TPa - 5800 K, respectively. In contrast to SiO2, melting and metallization of these compounds do not coincide implying the presence of poor electrically conducting liquids close to the melting lines. This has important implications for the generation of dynamos in Super-earths mantles.

  18. Photosynthetic capacity, nutrient status and growth of maize (Zea mays L. upon MgSO4 leaf-application

    Mareike eJezek


    Full Text Available The major plant nutrient magnesium is involved in numerous physiological processes and its deficiency can severely reduce the yield and quality of crops. Since Mg availability in soil and uptake into the plant is often limited by unfavorable soil or climatic conditions, application of Mg onto leaves, the site with highest physiological Mg demand, might be a reasonable alternative fertilization strategy. This study aimed to investigate, if MgSO4 leaf-application in practically relevant amounts can efficiently alleviate the effects of Mg starvation in maize, namely reduced photosynthesis capacity, disturbed ion homeostasis and growth depression. Results clearly demonstrated that Mg deficiency could be mitigated by MgSO4 leaf-application as efficiently as by resupply of MgSO4 via the roots in vegetative maize plants. Significant increases in SPAD values and net rate of CO2-assimilation as well as enhanced shoot biomass have been achieved. Ion analysis furthermore revealed an improvement of the nutrient status of Mg-deficient plants with regard to [Mg], [K] and [Mn] in distinct organs, thereby reducing the risk of Mn-toxicity at the rootside, which often occurs together with Mg deficiency on acid soils. In conclusion, foliar fertilization with Mg proved to be an efficient strategy to adequately supply maize plants with magnesium and might hence be of practical relevance to correct nutrient deficiencies during the growing season.

  19. Nano-engineering approach to destabilization of magnesium hydride (MgH2) by solid-state reaction with Si.

    Bystrzycki, J; Polanski, M; Plocinski, T


    We studied a possibility of destabilization of MgH2 by chemical reaction with Si by using a nano-engineering method for reducing diffusion distances and increasing surface area. The structure, morphology, chemical composition and dehydriding properties were investigated by XRD, SEM, EDS, DTA-TG and the volumetric Sievert method. The commercial MgH2 and Si powder mixture corresponded to the stoichiometry of the ideal Mg2Si intermetallic compound was ball-milled under argon atmosphere to reach a nanocrystalline composite structure (MgH2-Si mixture leads to the formation only a small amount of the Mg2Si compound. Microstructural studies showed that Si after ball-milling is heterogeneously distributed on the surface of MgH2 particles and incorporated in the nanocrystalline MgH2 matrix, forming a nanocomposite structure. The sluggish destabilization of MgH2 by solid-state reaction with Si forming the Mg2Si intermetallic compound was observed at 250 degrees C. The XRD and EDS analysis confirmed that the Mg2Si compound is formed after the dehydrogenation of the synthesized MgH2-Si composite. The activation energy of the destabilization reaction for the investigated composite significantly decreased (162 kJ/mol) as compared with unmilled MgH2-Si powder mixture (213 kJ/mol).

  20. [Fluconazole 1200mg or 800mg for cryptococcal meningitis treatment in Ivory Coast].

    Kouakou, G A; Ello, N F; Kassi, N A; Keita, M; Doumbia, A; Mossou, C; Kassi, F K; Tanon, A; Ehui, E; Eholié, S P


    Assessing the use of high-dose fluconazol monotherapy (1200mg or 800mg) in the treatment and prognosis of HIV-associated cryptococcal meningitis in Ivory Coast. A retrospective study carried out from August 2008 to August 2011 based on patients charts suffering from CM in the Abidjan Tropicals and Infectious Disease Unit. Mortality rate and associated factors were analyzed. Forty-six cases of cryptococcal meningitis (2.5% of hospitalizations) were included. The sex-ratio was of 1.2. The median age was 40.5 [35-47] years. The symptomatology was subacute (93.5%). The main clinical symptoms were syndrome of pure meningeal irritation (65%), fever (100%); 35% of patients had encephalomeningits. Twenty-one (45.7%) was ART-naïve patients. Fluconazole 1200mg was prescribed to 29 (63%) patients. Therapeutic lumbar punctures were performed in 42 (91.3) patients. The mortality rate was 50%. Significant predictors of mortality were encephalomeningitis and therapeutic lumbar puncture. Cryptococcal meningitis associated mortality remains high despite the use of high-dose fluconazole monotherapy. Therapeutic lumbar punctures help to improving the prognosis. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  1. Combinatorial search for hydrogen storage alloys: Mg-Ni and Mg-Ni-Ti

    Oelmez, Rabia; Cakmak, Guelhan; Oeztuerk, Tayfur [Dept. of Metallurgical and Materials Engineering, Middle East Technical University, 06531 Ankara (Turkey)


    A combinatorial study was carried out for hydrogen storage alloys involving processes similar to those normally used in their fabrication. The study utilized a single sample of combined elemental (or compound) powders which were milled and consolidated into a bulk form and subsequently deformed to heavy strains. The mixture was then subjected to a post annealing treatment, which brings about solid state reactions between the powders, yielding equilibrium phases in the respective alloy system. A sample, comprising the equilibrium phases, was then pulverized and screened for hydrogen storage compositions. X-ray diffraction was used as a screening tool, the sample having been examined both in the as processed and the hydrogenated state. The method was successfully applied to Mg-Ni and Mg-Ni-Ti yielding the well known Mg{sub 2}Ni as the storage composition. It is concluded that a partitioning of the alloy system into regions of similar solidus temperature would be required to encompass the full spectrum of equilibrium phases. (author)

  2. Field demonstration of age dependent increase in lead phytoextraction by Pelargonium cultivar

    Shahid, Muhammad; Arshad, Muhammad; Pinelli, Eric; Alric, Alain; Kaemmerer, Michel; Pradere, Philippe; Dumat, Camille


    Unnecessary for living organisms, lead (Pb) is one of the major widespread toxic metals found in the environment with potential danger to human health and to ecosystems (Shahid et al. 2012). Lead is known to induce a broad range of toxic effects to living organism, including those that are morphological, physiological and biochemical in origin (Pourrut et al. 2011). A field study was carried out in the vicinity of Pb recycling plant near Toulouse-France, and contaminated by atmospheric fallouts to evaluate lead extraction and uptake efficiency of hyperaccumulater Attar of Roses Pelargonium cultivar. It was found that Attar of Roses has ability to accumulate (8644 mgPb/kg DW plant) and survive on highly contaminated acidic soil (39250 mg kg-1 of total Pb) without any morpho-phytotoxicity symptoms. Moreover Attar showed increased extraction of lead from bulk soil to rhizosphere through Pb mobilization and ultimately increased uptake by roots and translocation to shoots. The studied contaminated soil could be cleaned up in few years by planting hyperaccumulater Attar of Rose for longer time period. Under optimum fertlization, irrigation and use of natural or synthetic chelates (EDTA, LMOWA, humic substances etc.) along with old Attar of rose plants, time requires for complete remediation of contaminated site can be reduced to practically applicable time period. Moreover, the use of Pelargonium for remediation has several additional practical, esthetical and economic advantages. The extraction of value-added essential oils from harvested biomass could offset the cost of deploying phytoremediation and renders it as a viable approach for remediating highly contaminated soils, on large scale. Keywords: metal uptake, Pelargonium, phytoremediation, cultivar, soil-plant transfer and kinetic. References Pourrut, B., Shahid, M., Dumat, C., Winterton, P., Pinelli, E., 2011a. Lead uptake, toxicity and detoxification in plants. Rev. Environ. Contam. Toxicol. 213, 113-136. Shahid

  3. Exposure of adolescent mice to 3,4-methylenedioxypyrovalerone increases the psychostimulant, rewarding and reinforcing effects of cocaine in adulthood.

    López-Arnau, R; Luján, M A; Duart-Castells, L; Pubill, D; Camarasa, J; Valverde, O; Escubedo, E


    3,4-Methylenedioxypyrovalerone (MDPV) is a synthetic cathinone with powerful psychostimulant effects. It selectively inhibits the dopamine transporter (DAT) and is 10-50-fold more potent as a DAT blocker than cocaine, suggesting a high abuse liability. The main objective of the present study was to assess the consequences of an early (adolescence) MDPV exposure on the psychostimulant, rewarding and reinforcing effects induced by cocaine i