Levels of 2-dodecylcyclobutanone in ground beef patties irradiated by low-energy X-ray and gamma rays.

Science.gov (United States)

Hijaz, Faraj M; Smith, J Scott

2010-01-01

Food irradiation improves food safety and maintains food quality by controlling microorganisms and extending shelf life. However, acceptance and commercial adoption of food irradiation is still low. Consumer groups such as Public Citizen and the Food and Water Watch have opposed irradiation because of the formation of 2-alkylcyclobutanones (2-ACBs) in irradiated, lipid-containing foods. The objectives of this study were to measure and to compare the level of 2-dodecylcyclobutanone (2-DCB) in ground beef irradiated by low-energy X-rays and gamma rays. Beef patties were irradiated by low-energy X-rays and gamma rays (Cs-137) at 3 targeted absorbed doses of 1.5, 3.0, and 5.0 kGy. The samples were extracted with n-hexane using a Soxhlet apparatus, and the 2-DCB concentration was determined with gas chromatography-mass spectrometry. The 2-DCB concentration increased linearly (P irradiation dose for gamma-ray and low-energy X-ray irradiated patties. There was no significant difference in 2-DCB concentration between gamma-ray and low-energy X-ray irradiated patties (P > 0.05) at all targeted doses. © 2010 Institute of Food Technologists®

2-Dodecylcyclobutanone, a radiolytic product of palmitic acid, is genotoxic in primary human colon cells and in cells from preneoplastic lesions

International Nuclear Information System (INIS)

Knoll, Nadine; Weise, Anja; Claussen, Uwe; Sendt, Wolfgang; Marian, Brigitte; Glei, Michael; Pool-Zobel, Beatrice L.

2006-01-01

The irradiation of fat results in the formation of 2-alkylcyclobutanones, a new class of food contaminants. Results of previous in vitro studies with primary human colon cells and in vivo experiments with rats fed with 2-alkylcyclobutanones indicated that these radiolytic derivatives may be genotoxic and enhance the progression of colon tumors. The underlying mechanisms of these effects, however, are not clearly understood. Therefore we performed additional investigations to elucidate the genotoxic potential of 2-dodecylcyclobutanone (2dDCB) that is generated from palmitic acid. In particular, we explored the relative sensitivities of human colon cells, representing different stages of tumor development and healthy colon tissues, respectively. HT29clone19A cells, LT97 adenoma cells and primary human epithelial cells were exposed to 2dDCB (150-2097 μM). We determined cytotoxic effects using trypan blue exclusion. Genotoxicity, reflected as strand breaks, was assessed using the alkaline version of the comet assay and chromosomal abnormalities were investigated by 24-color fluorescence-in-situ-hybridization. 2dDCB was cytotoxic in a time- and dose-dependent manner in LT97 adenoma cells and in freshly isolated primary cells but not in the human colon tumor cell line. Associated with this was a marked induction of DNA damage by 2dDCB in LT97 adenoma cells and in freshly isolated colonocytes, whereas in the HT29clone19A cells no strand breaks were detectable. A long-term incubation of LT97 adenoma cells with lower concentrations of 2dDCB revealed cytogenetic effects. In summary, 2dDCB was clearly genotoxic in healthy human colon epithelial cells and in cells representing preneoplastic colon adenoma. These findings provide additional evidence that this compound may be regarded as a possible risk factor for processes in colon carcinogenesis related to initiation and progression

Directional Atherectomy Followed by a Paclitaxel-Coated Balloon to Inhibit Restenosis and Maintain Vessel Patency

Science.gov (United States)

Langhoff, Ralf; Rocha-Singh, Krishna J.; Jaff, Michael R.; Blessing, Erwin; Amann-Vesti, Beatrice; Krzanowski, Marek; Peeters, Patrick; Scheinert, Dierk; Torsello, Giovanni; Sixt, Sebastian; Tepe, Gunnar

2017-01-01

Background— Studies assessing drug-coated balloons (DCB) for the treatment of femoropopliteal artery disease are encouraging. However, challenging lesions, such as severely calcified, remain difficult to treat with DCB alone. Vessel preparation with directional atherectomy (DA) potentially improves outcomes of DCB. Methods and Results— DEFINITIVE AR study (Directional Atherectomy Followed by a Paclitaxel-Coated Balloon to Inhibit Restenosis and Maintain Vessel Patency—A Pilot Study of Anti-Restenosis Treatment) was a multicenter randomized trial designed to estimate the effect of DA before DCB to facilitate the development of future end point-driven randomized studies. One hundred two patients with claudication or rest pain were randomly assigned 1:1 to DA+DCB (n=48) or DCB alone (n=54), and 19 additional patients with severely calcified lesions were treated with DA+DCB. Mean lesion length was 11.2±4.0 cm for DA+DCB and 9.7±4.1 cm for DCB (P=0.05). Predilation rate was 16.7% for DA+DCB versus 74.1% for DCB; postdilation rate was 6.3% for DA+DCB versus 33.3% for DCB. Technical success was superior for DA+DCB (89.6% versus 64.2%; P=0.004). Overall bail-out stenting rate was 3.7%, and rate of flow-limiting dissections was 19% for DCB and 2% for DA+DCB (P=0.01). One-year primary outcome of angiographic percent diameter stenosis was 33.6±17.7% for DA+DCB versus 36.4±17.6% for DCB (P=0.48), and clinically driven target lesion revascularization was 7.3% for DA+DCB and 8.0% for DCB (P=0.90). Duplex ultrasound patency was 84.6% for DA+DCB, 81.3% for DCB (P=0.78), and 68.8% for calcified lesions. Freedom from major adverse events at 1 year was 89.3% for DA+DCB and 90.0% for DCB (P=0.86). Conclusions— DA+DCB treatment was effective and safe, but the study was not powered to show significant differences between the 2 methods of revascularization in 1-year follow-up. An adequately powered randomized trial is warranted. Clinical Trial Registration— http

Directional Atherectomy Followed by a Paclitaxel-Coated Balloon to Inhibit Restenosis and Maintain Vessel Patency: Twelve-Month Results of the DEFINITIVE AR Study.

Science.gov (United States)

Zeller, Thomas; Langhoff, Ralf; Rocha-Singh, Krishna J; Jaff, Michael R; Blessing, Erwin; Amann-Vesti, Beatrice; Krzanowski, Marek; Peeters, Patrick; Scheinert, Dierk; Torsello, Giovanni; Sixt, Sebastian; Tepe, Gunnar

2017-09-01

Studies assessing drug-coated balloons (DCB) for the treatment of femoropopliteal artery disease are encouraging. However, challenging lesions, such as severely calcified, remain difficult to treat with DCB alone. Vessel preparation with directional atherectomy (DA) potentially improves outcomes of DCB. DEFINITIVE AR study (Directional Atherectomy Followed by a Paclitaxel-Coated Balloon to Inhibit Restenosis and Maintain Vessel Patency-A Pilot Study of Anti-Restenosis Treatment) was a multicenter randomized trial designed to estimate the effect of DA before DCB to facilitate the development of future end point-driven randomized studies. One hundred two patients with claudication or rest pain were randomly assigned 1:1 to DA+DCB (n=48) or DCB alone (n=54), and 19 additional patients with severely calcified lesions were treated with DA+DCB. Mean lesion length was 11.2±4.0 cm for DA+DCB and 9.7±4.1 cm for DCB ( P =0.05). Predilation rate was 16.7% for DA+DCB versus 74.1% for DCB; postdilation rate was 6.3% for DA+DCB versus 33.3% for DCB. Technical success was superior for DA+DCB (89.6% versus 64.2%; P =0.004). Overall bail-out stenting rate was 3.7%, and rate of flow-limiting dissections was 19% for DCB and 2% for DA+DCB ( P =0.01). One-year primary outcome of angiographic percent diameter stenosis was 33.6±17.7% for DA+DCB versus 36.4±17.6% for DCB ( P =0.48), and clinically driven target lesion revascularization was 7.3% for DA+DCB and 8.0% for DCB ( P =0.90). Duplex ultrasound patency was 84.6% for DA+DCB, 81.3% for DCB ( P =0.78), and 68.8% for calcified lesions. Freedom from major adverse events at 1 year was 89.3% for DA+DCB and 90.0% for DCB ( P =0.86). DA+DCB treatment was effective and safe, but the study was not powered to show significant differences between the 2 methods of revascularization in 1-year follow-up. An adequately powered randomized trial is warranted. http://www.clinicaltrials.gov. Unique Identifier: NCT01366482. Copyright © 2017 The

Detection of irradiated prawns using 2-alkyl-cyclobutanones

International Nuclear Information System (INIS)

McMurray, B.T.; Hamilton, J.T.G.; Stevenson, M.H.

1994-01-01

The use of ionizing radiation for the preservation of food has been under investigation for many years but yet has to receive worldwide acceptance. Although irradiation can be carefully controlled, it is generally accepted that the development of tests for detection of irradiated food would enhance consumer confidence and might help to enforce labelling regulations. The alkylcyclobutanones are reported to be the only cyclic compounds formed as the products of the radiolysis of saturated triglycerides. The synthesis of 2-dodecylcyclobutanone (DCB) and 2-tetradecylcyclobutanone (TCB) has been carried out. Using irradiated chicken meat as the model for a fat-containing food, both cyclobutanones have been extracted with solvent and then identified by gas chromatography-mass spectrometry. DCB and TCB have been detected in chicken meat irradiated at doses well below 10 kGy and were not detectable in unirradiated chicken. Systematic studies have been undertaken to confirm the specificity of these compounds as markers for irradiation treatment. The presence of both DCB and TCB in other irradiated meats and irradiated liquid whole egg has been confirmed. The feasibility of applying the method to low- fat-containing foods, such as prawns, is now underway. Preliminary studies have shown that both DCB and TCB have been detected in prawns irradiated at doses likely to be used commercially. 3 refs. (author)

Light-induced mutagenicity in Salmonella TA102 and genotoxicity/cytotoxicity in human T-cells by 3,3'-dichlorobenzidine: a chemical used in the manufacture of dyes and pigments and in tattoo inks

International Nuclear Information System (INIS)

Wang Lei; Yan Jian; Hardy, William; Mosley, Charity; Wang Shuguang; Yu Hongtao

2005-01-01

DCB, 3,3'-dichlorobenzidine, is used primarily as an intermediate in the manufacture of diarylide yellow or azo red pigments for printing ink, textile, paint, and plastics. It is also used in tattoo inks. In this article, we investigate light-induced toxicity of DCB in both bacteria and human Jurkat T-cells. DCB itself is not toxic or mutagenic to Salmonella typhimurium TA102, but is photomutagenic at concentrations as low as 2 μM and phototoxic at concentrations >100 μM when bacteria are exposed to DCB and light at the same time (1.2 J/cm 2 of UVA and 2.1 J/cm 2 of visible light). Furthermore, DCB is both photocytotoxic and photogenotoxic to human Jurkat T-cells. Under a light irradiation dose of 2.3 J/cm 2 of UVA and 4.2 J/cm 2 of visible light, it causes the Jurkat T-cells to become nonviable in a DCB dose-dependent manner and the nonviable cells reaches 60% at DCB concentrations higher than 50 μM. At the same time, DNA fragmentation is observed for cells exposed to both DCB and light, determined by single cell gel electrophoresis (alkaline comet assay). As much as 5% (average) DNA fragmentation was observed when exposed to 200 μM DCB and light irradiation. This suggests that DCB can penetrate the cell membrane and enter the cell. Upon light activation, DCB in the cells can cause various cellular damages, leading to nonviable Jurkat T-cells. It appears, the nonviable cells are not caused solely by fragmentation of cellular DNA, but by other damages such as to proteins and cell membranes, or DNA alkylation. Therefore, persons exposed to DCB through environmental contamination or through tattoo piercing using DCB-containing inks must not only concern about its toxicity without exposing to light, but also its phototoxicity

Synthesis by plasma and characterization of compounds derived from polyacetylene

International Nuclear Information System (INIS)

Vasquez O, M.

2004-01-01

This work presents a study on, the synthesis by plasma and the characterization of an aliphatic conjugated polymer, polyacetylene-chlorinated (Pac), and two aromatic polymers, Poly pyrrole (P Py-Cl) and Poly thiophene (Pth-Cl) synthesized with chlorine and the electrical conductivity. The last two polymers were synthesized to compare the chlorine-polymer interaction in aliphatic and aromatic polymers synthesized by plasma and their repercussion on the electrical transport of charges in the material. The structure and morphology of the polymers were studied using scanning electron microscopy (Sem), energy dispersive spectroscopy (EDS), infrared spectroscopy (Ft-IR), conductivity analysis and X-Ray photon spectroscopy (XPS). The results showed that Pac is soluble in acetone and other organic solvents, which indicates a low proportion of crosslinking in the polymers. This point is important because the crosslinking reduces the electrical conductivity in the material. The Pac conductivity is in the range of 1 x 10 -12 to 6 x 10 -4 S/cm in the internal of 35- 90% of relative humidity. A possible mechanism for the transport of electrical charges in Pac is by means of the double and simple conjugated bonds in the polymers. Pth-Cl and P Py-Cl present electric conductivity in the interval of 9 x 10 -5 to 1 x 10 -2 S/cm and show a great dependence on the relative humidity. The chlorine addition in these polymers was through simultaneous polymerization with chloroform. This last compound can decompose if the energy of the plasma is relatively high, and the fragments can link to the polymer in a hybrid process of copolymerization. An important point of this work is that the polymer is soluble, a difference of the obtained via plasma as the poli aniline, P Py-CI and Pth-Cl both studied in this work. If took in account that the Pac is single the monomer and that P Py-Cl and Pth-CI is affected by the chlorine that modifies the conductivity of the material, then Pac presents an

Synthesis by plasma and characterization of compounds derived from polyacetylene; Sintesis por plasma y caracterizacion de compuestos derivados del poliacetileno

Energy Technology Data Exchange (ETDEWEB)

Vasquez O, M

2004-07-01

This work presents a study on, the synthesis by plasma and the characterization of an aliphatic conjugated polymer, polyacetylene-chlorinated (Pac), and two aromatic polymers, Poly pyrrole (P Py-Cl) and Poly thiophene (Pth-Cl) synthesized with chlorine and the electrical conductivity. The last two polymers were synthesized to compare the chlorine-polymer interaction in aliphatic and aromatic polymers synthesized by plasma and their repercussion on the electrical transport of charges in the material. The structure and morphology of the polymers were studied using scanning electron microscopy (Sem), energy dispersive spectroscopy (EDS), infrared spectroscopy (Ft-IR), conductivity analysis and X-Ray photon spectroscopy (XPS). The results showed that Pac is soluble in acetone and other organic solvents, which indicates a low proportion of crosslinking in the polymers. This point is important because the crosslinking reduces the electrical conductivity in the material. The Pac conductivity is in the range of 1 x 10{sup -12} to 6 x 10{sup -4} S/cm in the internal of 35- 90% of relative humidity. A possible mechanism for the transport of electrical charges in Pac is by means of the double and simple conjugated bonds in the polymers. Pth-Cl and P Py-Cl present electric conductivity in the interval of 9 x 10{sup -5} to 1 x 10{sup -2} S/cm and show a great dependence on the relative humidity. The chlorine addition in these polymers was through simultaneous polymerization with chloroform. This last compound can decompose if the energy of the plasma is relatively high, and the fragments can link to the polymer in a hybrid process of copolymerization. An important point of this work is that the polymer is soluble, a difference of the obtained via plasma as the poli aniline, P Py-CI and Pth-Cl both studied in this work. If took in account that the Pac is single the monomer and that P Py-Cl and Pth-CI is affected by the chlorine that modifies the conductivity of the material

DMSP-consuming bacteria associated with the calanoid copepod Acartia tonsa (Dana)

DEFF Research Database (Denmark)

Tang, K.W.; Visscher, P.T.; Dam, H.G.

2001-01-01

DMSP-consuming bacteria (DCB) were recovered from the body and fecal pellets of the copepod Acartia tonsa (Dana). The most probable number of DCB associated with starved A. tonsa was 9.2 X 10(2) cells copepod(-1). The abundance of DCB recovered from the copepod body increased to 1.6-2.8 X 10......(4) after the copepod fed on DMSP-containing alga. DCB abundance associated with fecal pellets averaged 1.2 X 10(4) cells pellet(-1). In enrichment cultures, the DCB grew with a doubling time of 1.1- 2.9 days, and consumed DMSP at a rate of 4.5-7.5 fmol cell(-1) day(-1). The apparent DMSP-to-DMS conversion...... Elsevier Science B.V. All rights reserved....

German Center Subanalysis of the LEVANT 2 Global Randomized Study of the Lutonix Drug-Coated Balloon in the Treatment of Femoropopliteal Occlusive Disease.

Science.gov (United States)

Scheinert, Dierk; Schmidt, Andrej; Zeller, Thomas; Müller-Hülsbeck, Stefan; Sixt, Sebastian; Schröder, Henrik; Weiss, Norbert; Ketelsen, Dominik; Ricke, Jens; Steiner, Sabine; Rosenfield, Kenneth

2016-06-01

To report a subanalysis of the German centers enrolling patients in the prospective, global, multicenter, randomized LEVANT 2 pivotal trial (ClinicalTrials.gov identifier NCT01412541) of the Lutonix drug-coated balloon (DCB) for the treatment of femoropopliteal occlusive disease. Among the 476 patients in LEVANT 2, 126 patients (mean age 67.1±9.6 years; 79 men) were enrolled at the 8 participating German sites between August 2011 and July 2012 and were randomized 2:1 to treatment with the Lutonix DCB (n=83) vs an uncoated balloon during percutaneous transluminal angioplasty (PTA, n=43). All patients had intermittent claudication or rest pain (Rutherford categories 2-4). Average lesion length was 58 mm and average treated length was 100 mm. Severe calcification was present in 11% of lesions, and 23% were total occlusions. The efficacy outcome was primary patency at 12 months, and the safety outcome was 12-month freedom from a composite of perioperative death, index limb-related death, amputation (below or above the ankle), and index limb revascularization. Secondary endpoints included target lesion revascularization (TLR), major adverse events, and functional outcomes. Demographic, clinical, and lesion characteristics were matched between Lutonix DCB and PTA groups, as were the final percent diameter stenosis (19%) and procedure success (91%). By Kaplan-Meier analysis, the 12-month primary patency rate was 80% vs 58% (p=0.015) and the composite safety endpoint rate was 94% vs 72% (p=0.001), respectively. Freedom from TLR was higher for DCBs (96%) vs PTA (82%, p=0.012). Major adverse events were similar for both groups. The benefit favoring DCB over PTA was observed in German men and women. Compared to the non-German LEVANT 2 cohort, there was a shorter time between insertion and inflation of treatment balloons (21.8 vs 39.5 seconds, pGerman cohort. Balloons were inflated to higher pressures (9.0 vs 7.7 atm, pGerman cohort had a higher baseline stenosis, final

Mid-term outcomes of orbital atherectomy combined with drug-coated balloon angioplasty for treatment of femoropopliteal disease.

Science.gov (United States)

Foley, T Raymond; Cotter, Ryan P; Kokkinidis, Damianos G; Nguyen, Daniel D; Waldo, Stephen W; Armstrong, Ehrin J

2017-05-01

To assess the intraprocedural and mid-term outcomes of orbital atherectomy (OA) combined with drug-coated balloon (DCB) angioplasty for the treatment of calcified femoropopliteal disease. In this single-center cohort, 89 patients (139 lesions) were treated with DCB angioplasty for claudication or critical limb ischemia (CLI). Angiographic characteristics and procedural outcomes were reviewed for patients treated with or without adjunctive OA. Lesion calcification was graded using two previously published scoring systems, the angiographic calcium score (ACS) and the peripheral artery calcification scoring system (PACSS). Among 139 lesions, 40 (29%) were treated with OA + DCB. Mean lesion length was 135 ± 100 mm for lesions treated with OA + DCB and 139 ± 100 mm for DCB alone (P = 0.9). Moderate to severe calcification was present in 83% of patients treated with OA, compared to 42% of patients treated with DCB alone (P < 0.001). Lesions treated with OA + DCB were less likely to require bailout stenting (18% vs. 39%, P =0.01). Rates of embolization (0% in OA + DCB vs. 2% in DCB only, P = 0.4), dissection (13% vs. 14%, P = 0.8), and perforation (0%) did not differ significantly between groups. The freedom from TLR at 1 year was 82% in both groups (P = 0.6) while primary patency was 81% in-patients treated with DCB alone and 77% in-patients treated with DCB with concomitant OA (P = 0.8). In this single-center analysis of patients undergoing DCB angioplasty for claudication or CLI, OA was most often used for the treatment of severely calcified lesions. These lesions were more likely to be treated with scoring balloons and less likely to require bailout stenting. At 1 year, target lesion revascularization and primary patency was similar in patients treated with and without adjunctive OA, despite the higher lesion complexity among those receiving the combination procedure. © 2017 Wiley Periodicals, Inc. © 2017 Wiley

Surfactant flushing remediation of o-dichlorobenzene and p-dichlorobenzene contaminated soil.

Science.gov (United States)

Pei, Guangpeng; Zhu, Yuen; Cai, Xiatong; Shi, Weiyu; Li, Hua

2017-10-01

Surfactant-enhanced remediation is used to treat dichlorobenzene (DCB) contaminated soil. In this study, soil column experiments were conducted to investigate the removal efficiencies of o-dichlorobenzene (o-DCB) and p-dichlorobenzene (p-DCB) from contaminated soil using micellar solutions of biosurfactants (saponin, alkyl polyglycoside) compare to a chemically synthetic surfactant (Tween 80). Leachate was collected and analyzed for o-DCB and p-DCB content. In addition, soil was analyzed to explore the effect of surfactants on soil enzyme activities. Results showed that the removal efficiency of o-DCB and p-DCB was highest for saponin followed by alkyl polyglycoside and Tween 80. The maximum o-DCB and p-DCB removal efficiencies of 76.34% and 80.43%, respectively, were achieved with 4 g L -1 saponin solution. However, an opposite result was observed in the cumulative mass of o-DCB and p-DCB in leachate. The cumulative extent of o-DCB and p-DCB removal by the biosurfactants saponin and alkyl polyglycoside was lower than that of the chemically synthetic surfactant Tween 80 in leachate. Soil was also analyzed to explore the effect of surfactants on soil enzyme activities. The results indicated that surfactants were potentially effective in facilitating soil enzyme activities. Thus, it was confirmed that the biosurfactants saponin and alkyl polyglycoside could be used for remediation of o-DCB and p-DCB contaminated soil. Copyright © 2017 Elsevier Ltd. All rights reserved.

Directional Atherectomy With Antirestenotic Therapy vs Drug-Coated Balloon Angioplasty Alone for Isolated Popliteal Artery Lesions.

Science.gov (United States)

Stavroulakis, Konstantinos; Schwindt, Arne; Torsello, Giovanni; Stachmann, Arne; Hericks, Christiane; Bosiers, Michel J; Beropoulis, Efthymios; Stahlhoff, Stefan; Bisdas, Theodosios

2017-04-01

To report a single-center study comparing drug-coated balloon (DCB) angioplasty vs directional atherectomy with antirestenotic therapy (DAART) for isolated lesions of the popliteal artery. Seventy-two patients were treated with either DCB angioplasty alone (n=31) or with DAART (n=41) for isolated popliteal artery stenotic disease between October 2009 and December 2015. The majority of patients presented with lifestyle-limiting claudication (74% vs 86%, respectively). Vessel calcification (29% vs 29%, respectively), mean lesion length (47 vs 42 mm, respectively), and number of runoff vessels were comparable between the groups. The primary outcome measure was primary patency; secondary outcomes were technical success (<30% residual stenosis or bailout stenting), secondary patency, and freedom from clinically driven target lesion revascularization (TLR). The technical success rate following DCB was 84% vs 93% (p=0.24) after DAART. The 12-month primary patency rate was significantly higher in the DAART group (65% vs 82%; hazard ratio 2.64, 95% confidence interval 1.09 to 6.37, p=0.021), while freedom from TLR did not differ between the 2 treatment strategies (82% vs 94%, p=0.072). Secondary patency at 12 months was identical for both groups (96% vs 96%). Although not statistically significant, bailout stenting was more common after DCB angioplasty (16% vs 5% for DAART, p=0.13) and aneurysmal degeneration of the popliteal artery was seen more often after DAART (7% vs 0% for DCB alone, p=0.25). Popliteal artery injury was observed in 2 patients treated using DAART (5% vs 0% for DCB alone, p=0.5), whereas distal embolization rates were comparable between the groups (3% for DCB alone vs 5% for DAART, p=0.99). In this study, the use of DAART was associated with a higher primary patency rate compared with DCB angioplasty for isolated popliteal lesions. Nonetheless, both treatment options were associated with excellent 12-month secondary patency. Aneurysmal degeneration of

Detection of irradiated chicken by 2-alkylcyclobutanone analysis

International Nuclear Information System (INIS)

Tanabe, Hiroko; Goto, Michiko; Miyahara, Makoto

2001-01-01

Chicken meat irradiated at 0.5 kGy or higher doses were identified by GC/MS method analyzing 2-dodecylcyclobutanone (2-DCB) and 2-tetradecylcyclobutanone (2-TCB), which are formed from palmitic acid and stearic acid respectively, and isolated using extraction procedures of soxhlet-florisil chromatography. Many fat-containing foods have oleic acid in abundance as parent fatty acid, and chicken meat contains palmitoleic acid to the amount as much as stearic acid. In this study, we detected 2-tetradec-5'-enylcyclobutanone (2-TeCB) and 2-dodec-5'-enylcyclobutanone (2-DeCB) in chicken meat, which are formed from oleic acid and palmitoleic acid by irradiation respectively, using GC/MS method. Sensitivity in detection of both 2-TeCB and 2-DeCB were lower than that of 2-DCB. However, at least 0.57 μg/g/fat of 2-TeCB was detected in chicken meat irradiated at 0.5 kGy, so 2-TeCB seems to be a useful marker for the identification of irradiated foods containing fat. On the contrary, 2-DeCB was not detected clearly at low doses. This suggests that 2-DeCB may be a useful marker for irradiated fat in the food having enough amount of palmitoleic acid needed to analysis. In addition, 2-tetradecadienylcyclobutanone, which is formed from linoleic acid was also found in chicken meat. (author)

Cell proliferation studies in rodent hepatocytes during 1,4-dichlorobenzene administration

International Nuclear Information System (INIS)

Eldridge, S.R.; Tilbury, L.F.; Randall, H.; Goldsworthy, T.L.; Butterworth, B.E.

1990-01-01

In the NTP bioassay, 1,4-dichlorobenzene (DCB) induced hepatocellular carcinomas in mice, but not in rats. Because DCB is not DNA reactive, a cell proliferation study under conditions of the bioassay was undertaken to determine whether increased cell proliferation might play a role in DCB-induced hepatocarcinogenicity. DCB was administered in corn oil by gavage at the highest bioassay dose to male B6C3F1 mice (600 mg/kg) and male F344 rats (300 mg/kg) for five consecutive days. Cell proliferation was detected by labeling hepatocytes with either 5-bromo-2'-deoxyuridine (BRDU) or 3 H-thymidine delivered during the entire treatment period by subcutaneously implanted osmotic pumps. An increase in liver weight as a percentage of body weight was observed in treated mice (6.7±0.6 vs. 5.9±0.2) and rats (4.7±0.1 vs. 4.0±0.2) compared to controls. No significant elevations in plasma enzymes were found in either treated species, indicating a lack of overt hepatotoxicity. Histopathological evaluation revealed no evidence of hepatotoxicity in either species. The percentage of hepatocytes in S-phase was increased approximately 10-fold in both treated mice and rats compared to the respective control animals. Mice exhibited a centrilobular pattern of labeled hepatocytes, whereas rat hepatocytes were labeled hepatocytes, whereas rat hepatocytes were labeled throughout the lobules. These data demonstrate the hepatic mitogenic activity of DCB in mice and rats. However, this response dose not correlate with DCB-induced hepatocarcinogenicity. Further studies are required to examine the extent, duration and nature of the proliferative response in order to understand the species-specific effects of DCB

A phase III trial of docetaxel/carboplatin versus mitomycin C/ifosfamide/cisplatin (MIC) or mitomycin C/vinblastine/cisplatin (MVP) in patients with advanced non-small-cell lung cancer: a randomised multicentre trial of the British Thoracic Oncology Group (BTOG1).

Science.gov (United States)

Booton, R; Lorigan, P; Anderson, H; Baka, S; Ashcroft, L; Nicolson, M; O'Brien, M; Dunlop, D; O'Byrne, K; Laurence, V; Snee, M; Dark, G; Thatcher, N

2006-07-01

Phase III studies suggest that non-small-cell lung cancer (NSCLC) patients treated with cisplatin-docetaxel may have higher response rates and better survival compared with other platinum-based regimens. We report the final results of a randomised phase III study of docetaxel and carboplatin versus MIC or MVP in patients with advanced NSCLC. Patients with biopsy proven stage III-IV NSCLC not suitable for curative surgery or radiotherapy were randomised to receive four cycles of either DCb (docetaxel 75 mg/m(2), carboplatin AUC 6), or MIC/MVP (mitomycin 6 mg/m(2), ifosfamide 3 g/m(2) and cisplatin 50 mg/m(2) or mitomycin 6 mg/m(2), vinblastine 6 mg/m(2) and cisplatin 50 mg/m(2), respectively), 3 weekly. The primary end point was survival, secondary end points included response rates, toxicity and quality of life. The median follow-up was 17.4 months. Overall response rate was 32% for both arms (partial response = 31%, complete response = 1%); 32% of MIC/MVP and 26% of DCb patients had stable disease. One-year survival was 39% and 35% for DCb and MIC/MVP, respectively. Two-year survival was 13% with both arms. Grade 3/4 neutropenia (74% versus 43%, P MVP. The MIC/MVP arm had significant worsening in overall EORTC score and global health status whereas the DCb arm showed no significant change. The combination of DCb had similar efficacy to MIC/MVP but quality of life was better maintained.

Direct observation of the effects of cellulose synthesis inhibitors using live cell imaging of Cellulose Synthase (CESA) in Physcomitrella patens.

Science.gov (United States)

Tran, Mai L; McCarthy, Thomas W; Sun, Hao; Wu, Shu-Zon; Norris, Joanna H; Bezanilla, Magdalena; Vidali, Luis; Anderson, Charles T; Roberts, Alison W

2018-01-15

Results from live cell imaging of fluorescently tagged Cellulose Synthase (CESA) proteins in Cellulose Synthesis Complexes (CSCs) have enhanced our understanding of cellulose biosynthesis, including the mechanisms of action of cellulose synthesis inhibitors. However, this method has been applied only in Arabidopsis thaliana and Brachypodium distachyon thus far. Results from freeze fracture electron microscopy of protonemal filaments of the moss Funaria hygrometrica indicate that a cellulose synthesis inhibitor, 2,6-dichlorobenzonitrile (DCB), fragments CSCs and clears them from the plasma membrane. This differs from Arabidopsis, in which DCB causes CSC accumulation in the plasma membrane and a different cellulose synthesis inhibitor, isoxaben, clears CSCs from the plasma membrane. In this study, live cell imaging of the moss Physcomitrella patens indicated that DCB and isoxaben have little effect on protonemal growth rates, and that only DCB causes tip rupture. Live cell imaging of mEGFP-PpCESA5 and mEGFP-PpCESA8 showed that DCB and isoxaben substantially reduced CSC movement, but had no measureable effect on CSC density in the plasma membrane. These results suggest that DCB and isoxaben have similar effects on CSC movement in P. patens and Arabidopsis, but have different effects on CSC intracellular trafficking, cell growth and cell integrity in these divergent plant lineages.

Detection of some irradiated foods

International Nuclear Information System (INIS)

NASR, E.H.A

2009-01-01

This study was performed to investigate the possibility of using two rapid methods namely Supercritical Fluid Extraction (SFE) and Direct Solvent Extraction (DSE) methods for extraction and isolation of 2-dodecylcyclobutanone (2-DCB) followed by detecting this chemical marker by Gas chromatography technique and used this marker for identification of irradiated some foods containing fat (beef meat, chicken, camembert cheese and avocado) post irradiation, during cold and frozen storage. Consequently, this investigation was designed to study the following main points:- 1- The possibility of applying SFE-GC and DSE-GC rapid methods for the detection of 2-DCB from irradiated food containing fat (beef meat, chicken, camembert cheese and avocado fruits) under investigation.2-Studies the effect of gamma irradiation doses on the concentration of 2-DCB chemical marker post irradiation and during frozen storage at -18 degree C of chicken and beef meats for 12 months.3-Studies the effect of gamma irradiation doses on the concentration of 2-DCB chemical marker post irradiation and during cold storage at 4±1 degree C of camembert cheese and avocado fruits for 20 days.

Drug-coated balloon angioplasty after directional atherectomy improves outcome in restenotic femoropopliteal arteries.

Science.gov (United States)

Sixt, Sebastian; Carpio Cancino, Oscar Gerardo; Treszl, András; Beschorner, Ulrich; Macharzina, Roland; Rastan, Aljoscha; Krankenberg, Hans; Neumann, Franz-Josef; Zeller, Thomas

2013-09-01

Restenosis remains an unresolved problem despite different treatment modalities and new stent technology in femoropopliteal arteries. No standard therapy has proven to provide acceptable outcome data for this entity. Directional atherectomy alone did not result in satisfactory long-term patency rates. The outcome might be improved in conjunction with drug-coated balloon angioplasty. In this retrospective study, restenotic lesions of the femoropopliteal arteries were treated with directed atherectomy in 89 lesions of consecutive patients (58% male; mean age, 69 ± 11 years). All patients received adjunctive treatment with conventional balloon percutaneous angioplasty (PTA; n = 60) or drug-coated balloon angioplasty (DCB; n = 29). Lesion location was in the stent (DCB [n = 27] vs PTA [n = 36]) and in native restenotic vessels (DCB [n = 2] vs PTA [n = 25]). The 1-year Kaplan-Meier freedom from restenosis estimates (95% confidence intervals) in the DCB and PTA groups were 84.7% (70.9%-98.5%) and 43.8% (30.5%-57.1%), respectively. In a multivariable Cox model for restenosis, DCB treatment had a hazard ratio (95% confidence interval) of 0.28 (0.12-0.66; P = .0036) compared with the PTA group. In the multivariable model for procedural success, the effect of treatment did not differ between PTA and DCB (P = .134). The combination of directed atherectomy with adjunctive DCB is associated with a better event-free survival at 12 months of follow-up compared with PTA after directed atherectomy. Copyright © 2013 Society for Vascular Surgery. Published by Mosby, Inc. All rights reserved.

Spectral and thermodynamic properties for the exciplexes of N-alkyl carbazoles with dicyanobenzenes in THF

Science.gov (United States)

Asim, Sadia; Mansha, Asim; Landgraf, Stephan; Grampp, Günter; Zahid, Muhammad; Bhatti, Haq Nawaz

2014-01-01

The exciplex emission spectra of N-ethylcarbazole with 1,2-dicyanobenzene (NEC/1,2-DCB), N-methylcarbazole with 1,2-dicyanobenzene (NMC/1,2-DCB), 1,3-dicyanobenzene (NMC/1,3-DCB), and 1,4-dicyanobenzene (NMC/1,4-DCB) are studied in tetrahydrofuran (THF) for the temperature range starting from 253 K to 334 K. Thermochromic shifts along with the spectral properties including change in peak intensities and the ratio of exciplex peak intensity to fluorophore peak intensity are studied. Effect of temperature on the energy of zero-zero transitions hνo‧, Huang-Rhys factor (S), Gauss broadening of vibronic level (σ) and the dominant high-frequency vibration (hνν) are also part of investigation. Enthalpy of exciplex formation (ΔHEX∗) calculated by the model proposed by A. Weller and the Gibb's energy of electron transfer (ΔGet∗) for all exciplex systems are also discussed in the present paper. All the exciplexes under study were observed to be dipolar in nature. The exciplex of the N-methylcarbazole/1,4-dicyanobenzene was found to be the most stable and the N-methylcarbazole/1,3-dicyanobenzene was the weakest exciplex system.

Consideration on detection of irradiated rainbow trout by ESR method and 2-alkylcyclobutanone analysis

International Nuclear Information System (INIS)

Tanabe, Hiroko; Goto, Michiko

2002-01-01

Relative ESR strength of rib, backbone and opercular bone from irradiated culture rainbow trout was direct proportional to dose between 0.56kGy and 5.7kGy. Relative ESR strength of rib was higher than that of backbone. Although only 5mg of otolith was obtained from one rainbow trout, bone density of otolith is so high that relative ESR strength of otolith showed about 20-fold higher value than that of rib. In GCMS-SIM analysis of RCB, radiolytic compounds of lipid of fish meat, the amount of both DCB and TCB formed, estimated from ion concentrations of m/z98, were direct proportional to dose between 1.1kGy and 11.1kGy. Neither DCB nor TCB was detected in unirradiated sample. The ratio of amount of DCB formed to amount of TCB formed was nearly 4.4, which is the ratio of palmitic acid content to stearic acid content in rainbow trout, denoted in Standard Tables of Food Composition in Japan; Lipid composition of Foods. Finally, we propose to use detection of radiolytic compound, RCB, and measurement of ESR of high-density bone together for reliable identification of irradiated fish. (author)

Consideration on detection of irradiated rainbow trout by ESR method and 2-alkylcyclobutanone analysis

International Nuclear Information System (INIS)

Tanabe, H.; Goto, M.

2002-01-01

R elative ESR strength of rib, backbone and opercular bone from irradiated culture rainbow trout was direct proportional to dose between 0.56kGy and 5.7kGy. Relative ESR strength of rib was higher than that of backbone. Although only 5mg of otolith was obtained from one rainbow trout, bone density of otolith is so high that relative ESR strength of otolith showed about 20-fold higher value than that of rib. In GCMS-SIM analysis of RGB, radiolytic compounds of lipid of fish meat, the amount of both DCB and TCB formed, estimated from ion concentrations of m/z98, were direct proportional to dose between 1.1kGy and 11.1kGy. Neither DCB nor TCB was detected in unirradiated sample. The ratio of amount of DCB formed to amount of TCB formed was nearly 4.4, which is the ratio of palmitic acid content to stearic acid content in rainbow trout, denoted in Standard Tables of Food Composition in Japan; Lipid composition of Foods. Finally, we propose to use detection of radiolytic compound, RCB, and measurement of ESR of high-density bone together for reliable identification of irradiated fish

In vivo spin-trapping of the metabolites of 3,3'-dichlorobenzidine

International Nuclear Information System (INIS)

Iba, M.M.; Ghoshal, A.; Poyer, J.L.; Downs, P.; Massion, W.H.

1990-01-01

The carcinogen 3,3'-dichlorobenzidine (DCB) is bioactivated by liver enzymes to lipid-binding derivatives. To characterize the intermediates involved, male rats were treated with 14 C[U]DCB (100 mg, po and ip), followed 4 hr later by the spin trap ∝ phenyl-N-tert-butyl nitrone [(PBN), 50 mg, po and ip]. The rats were sacrificed 30 min after PBN treatment and the livers isolated and homogenized in CHCl 3 :CH 3 OH (2:1, v:v). The Folch extracts were analyzed by electron spin resonance (esr) spectroscopy, TLC and HPLC. The solvent extract yielded a 6-line spectrum by esr spectroscopy characteristic of a PBN adduct of an aryl radical. HPLC analysis of the extract revealed the presence of benzidine and a paramagnetic fraction which contained a PBN adduct of a DCB derivative. It is concluded that DCB undergoes reductive dehalogenation with aryl radicals as intermediates

The levels of polychlorinated biphenyls in 1,4-dichlorobenzene mothballs

Energy Technology Data Exchange (ETDEWEB)

Liu, Wenbin; Zheng, Minghui; Xing, Ying; Wang, Dongshen; Zhao, Xingru; Gao, Lirong [Chinese Academy of Sciences, Beijing (China). Key laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences

2004-09-15

The chemical 1,4-dichlorobenzene (p-DCB), also called paramoth, is one of the chemicals commonly used to make mothballs. For the more than 20 years, p-DCB has been used principally (35-55% of all uses) as a space deodorant for toilets and refuse containers, and as a fumigant for control of moths, molds, and mildews. The process of production of p-DCB currently used by industry is direct chlorination of benzene or chlorobenzene in the presence of a Friedel-Crafts catalyst (typically FeCl{sub 3}), and the pure products of p-DCB are obtained by distillation and crystallization from the mixture of polychlorinated benzenes. This process is similar to that of production of PCBs which were manufactured commercially by the progressive chlorination of biphenyl in the presence of a suitable catalyst, e.g., iron chloride. However, few studies on the formation of PCBs from chlorobenzenes have been published. Buser reported significant quantities of PCDFs and a small amount of PCDDs, PCBs, and chlorophenols were formed in the pyrolysis of chlorobenzenes at 620 C. Peng-Yan Liu et al. revealed that lower chlorinated benzenes produce more PCBs than higher ones. Nevertheless, prior to this study, no reports on PCBs in p-DCB and the restriction of PCBs in p-DCB products have been found. In this paper, the occurrence and distribution of dioxin-like PCBs and total PCBs in some commercial p-DCB mothballs are investigated. Except of the toxic of p-DCB, the low concentration of PCBs in p-DCB mothballs should not be negligible.

Removal of Malachite Green from aqueous solution using degreased coffee bean

International Nuclear Information System (INIS)

Baek, Mi-Hwa; Ijagbemi, Christianah Olakitan; O, Se-Jin; Kim, Dong-Su

2010-01-01

This study reports on the feasibility of employing degreased coffee beans (DCB) as adsorbent for Malachite Green (MG) removal in dyeing wastewater. The iodine value (IV), specific surface area (SSA) and porosity of the raw coffee beans (RCB) used in the study increased after the degreasing process, resulting in significant increase in the adsorption of MG onto DCB. Employing a batch experimental set-up, optimum conditions for complete color removal and adsorption of MG by DCB was studied considering parameters such as effect of degreasing process, adsorbent dosage, initial dye concentration, reaction temperature and pH. Adsorbed amount of MG by DCB increased with increasing DCB dosage and initial MG concentration. The rate of the adsorption reaction followed the pseudo second-order kinetics with the sorption isotherm well fitted to the Freundlich and the Langmuir isotherm models. Thermodynamic studies revealed that the adsorption processes is spontaneous and endothermic in nature. DCB has potentials for application as adsorbent for the removal of MG from dyeing process wastewater.

Removal of Malachite Green from aqueous solution using degreased coffee bean

Energy Technology Data Exchange (ETDEWEB)

Baek, Mi-Hwa; Ijagbemi, Christianah Olakitan; O, Se-Jin [Department of Environmental Science and Engineering, Ewha Womans University, Daehyundong 11-1, Seodaemungu, Seoul 120-750 (Korea, Republic of); Kim, Dong-Su, E-mail: dongsu@ewha.ac.kr [Department of Environmental Science and Engineering, Ewha Womans University, Daehyundong 11-1, Seodaemungu, Seoul 120-750 (Korea, Republic of)

2010-04-15

This study reports on the feasibility of employing degreased coffee beans (DCB) as adsorbent for Malachite Green (MG) removal in dyeing wastewater. The iodine value (IV), specific surface area (SSA) and porosity of the raw coffee beans (RCB) used in the study increased after the degreasing process, resulting in significant increase in the adsorption of MG onto DCB. Employing a batch experimental set-up, optimum conditions for complete color removal and adsorption of MG by DCB was studied considering parameters such as effect of degreasing process, adsorbent dosage, initial dye concentration, reaction temperature and pH. Adsorbed amount of MG by DCB increased with increasing DCB dosage and initial MG concentration. The rate of the adsorption reaction followed the pseudo second-order kinetics with the sorption isotherm well fitted to the Freundlich and the Langmuir isotherm models. Thermodynamic studies revealed that the adsorption processes is spontaneous and endothermic in nature. DCB has potentials for application as adsorbent for the removal of MG from dyeing process wastewater.

A modified carrier-to-code leveling method for retrieving ionospheric observables and detecting short-term temporal variability of receiver differential code biases

Science.gov (United States)

Zhang, Baocheng; Teunissen, Peter J. G.; Yuan, Yunbin; Zhang, Xiao; Li, Min

2018-03-01

Sensing the ionosphere with the global positioning system involves two sequential tasks, namely the ionospheric observable retrieval and the ionospheric parameter estimation. A prominent source of error has long been identified as short-term variability in receiver differential code bias (rDCB). We modify the carrier-to-code leveling (CCL), a method commonly used to accomplish the first task, through assuming rDCB to be unlinked in time. Aside from the ionospheric observables, which are affected by, among others, the rDCB at one reference epoch, the Modified CCL (MCCL) can also provide the rDCB offsets with respect to the reference epoch as by-products. Two consequences arise. First, MCCL is capable of excluding the effects of time-varying rDCB from the ionospheric observables, which, in turn, improves the quality of ionospheric parameters of interest. Second, MCCL has significant potential as a means to detect between-epoch fluctuations experienced by rDCB of a single receiver.

Correlating Coating Characteristics with the Performance of Drug-Coated Balloons – A Comparative In Vitro Investigation of Own Established Hydrogel- and Ionic Liquid-Based Coating Matrices

Science.gov (United States)

Kaule, Sebastian; Minrath, Ingo; Stein, Florian; Kragl, Udo; Schmidt, Wolfram; Schmitz, Klaus-Peter; Sternberg, Katrin; Petersen, Svea

2015-01-01

Drug-coated balloons (DCB), which have emerged as a therapeutic alternative to drug-eluting stents in percutaneous cardiovascular intervention, are well described with regard to clinical efficacy and safety within a number of clinical studies. In vitro studies elucidating the correlation between coating additive and DCB performance are however rare but considered important for the understanding of DCB requirements and the improvement of established DCB. In this regard, we examined three different DCB-systems, which were developed in former studies based on the ionic liquid cetylpyridinium salicylate, the body-own hydrogel hyaluronic acid and the pharmaceutically well-established hydrogel polyvinylpyrrolidone, considering coating morphology, coating thickness, drug-loss, drug-transfer to the vessel wall, residual drug-concentration on the balloon surface and entire drug-load during simulated use in an in vitro vessel model. Moreover, we investigated particle release of the different DCB during simulated use and determined the influence of the three coatings on the mechanical behavior of the balloon catheter. We could show that coating characteristics can be indeed correlated with the performance of DCB. For instance, paclitaxel incorporation in the matrix can reduce the drug wash-off and benefit a high drug transfer. Additionally, a thin coating with a smooth surface and high but delayed solubility can reduce drug wash-off and decrease particle burden. As a result, we suggest that it is very important to characterize DCB in terms of mentioned properties in vitro in addition to their clinical efficacy in order to better understand their function and provide more data for the clinicians to improve the tool of DCB in coronary angioplasty. PMID:25734818

Novel paclitaxel-coated angioplasty balloon catheter based on cetylpyridinium salicylate: Preparation, characterization and simulated use in an in vitro vessel model

Energy Technology Data Exchange (ETDEWEB)

Petersen, Svea, E-mail: svea.petersen@uni-rostock.de [Institute for Biomedical Engineering, University of Rostock, Friedrich-Barnewitz-Straße 4, 18119 Rostock (Germany); Kaule, Sebastian [Institute for Biomedical Engineering, University of Rostock, Friedrich-Barnewitz-Straße 4, 18119 Rostock (Germany); Stein, Florian [Institute for Chemistry, Analytical and Technical Chemistry University of Rostock, Albert-Einstein-Straße 3a, 18059 Rostock (Germany); Minrath, Ingo; Schmitz, Klaus-Peter [Institute for Biomedical Engineering, University of Rostock, Friedrich-Barnewitz-Straße 4, 18119 Rostock (Germany); Kragl, Udo [Institute for Chemistry, Analytical and Technical Chemistry University of Rostock, Albert-Einstein-Straße 3a, 18059 Rostock (Germany); Sternberg, Katrin [Institute for Biomedical Engineering, University of Rostock, Friedrich-Barnewitz-Straße 4, 18119 Rostock (Germany)

2013-10-15

Drug-coated balloons (DCB), which have emerged as therapeutic alternative to drug-eluting stents in percutaneous cardiovascular intervention, are well described with regard to clinical efficiency and safety within a number of clinical studies. In vitro studies elucidating the correlation of coating method and composition with DCB performance are however rare but considered important for the understanding of DCB requirements and the improvement of established DCB. In this context, we evaluated the applicability of a pipetting, dip-coating, and spray-coating process for the establishment of DCB based on paclitaxel (PTX) and the ionic liquid cetylpyridinium salicylate (Cetpyrsal) as novel innovative additive in three different compositions. Among tested methods and compositions, the pipetting process with 50 wt.% PTX resulted in most promising coatings as drug load was less controllable by the other processes and higher PTX contents led to considerable drug crystallization, as visualized by electron microscopy, accelerating PTX loss during short-term elution. Applying these conditions, homogeneous coatings could be applied on balloon catheter, whose simulated use in an in vitro vessel model revealed percental drug losses of 36 and 28% during transit and percental drug transfers of 12 and 40% under expansion for coatings applied in expanded and folded balloon condition, respectively. In comparison to literature values, these results support the high potential of Cetpyrsal as novel DCB matrix regarding low drug loss and efficient drug transfer. - Highlights: • We provide detailed in vitro data for definition of DCB coating requirements. • An in vitro vessel model for evaluating drug delivery from DCB is presented. • Innovative ionic liquid-based coatings for DCB are developed. • The coating shows low drug loss and efficient drug transfer.

Novel paclitaxel-coated angioplasty balloon catheter based on cetylpyridinium salicylate: Preparation, characterization and simulated use in an in vitro vessel model

International Nuclear Information System (INIS)

Petersen, Svea; Kaule, Sebastian; Stein, Florian; Minrath, Ingo; Schmitz, Klaus-Peter; Kragl, Udo; Sternberg, Katrin

2013-01-01

Drug-coated balloons (DCB), which have emerged as therapeutic alternative to drug-eluting stents in percutaneous cardiovascular intervention, are well described with regard to clinical efficiency and safety within a number of clinical studies. In vitro studies elucidating the correlation of coating method and composition with DCB performance are however rare but considered important for the understanding of DCB requirements and the improvement of established DCB. In this context, we evaluated the applicability of a pipetting, dip-coating, and spray-coating process for the establishment of DCB based on paclitaxel (PTX) and the ionic liquid cetylpyridinium salicylate (Cetpyrsal) as novel innovative additive in three different compositions. Among tested methods and compositions, the pipetting process with 50 wt.% PTX resulted in most promising coatings as drug load was less controllable by the other processes and higher PTX contents led to considerable drug crystallization, as visualized by electron microscopy, accelerating PTX loss during short-term elution. Applying these conditions, homogeneous coatings could be applied on balloon catheter, whose simulated use in an in vitro vessel model revealed percental drug losses of 36 and 28% during transit and percental drug transfers of 12 and 40% under expansion for coatings applied in expanded and folded balloon condition, respectively. In comparison to literature values, these results support the high potential of Cetpyrsal as novel DCB matrix regarding low drug loss and efficient drug transfer. - Highlights: • We provide detailed in vitro data for definition of DCB coating requirements. • An in vitro vessel model for evaluating drug delivery from DCB is presented. • Innovative ionic liquid-based coatings for DCB are developed. • The coating shows low drug loss and efficient drug transfer

Fabrication of blue luminescent MoS{sub 2} quantum dots by wet grinding assisted co-solvent sonication

Energy Technology Data Exchange (ETDEWEB)

Ali, Junaid; Siddiqui, Ghayas Uddin [Department of Mechatronics Engineering, Jeju National University, Jeju (Korea, Republic of); Choi, Kyung Hyun, E-mail: amm@jejunu.ac.kr [Department of Mechatronics Engineering, Jeju National University, Jeju (Korea, Republic of); Jang, Yunseok [Department of Printed Electronics, Korea Institute of Machinery & Materials, Daejeon, Republic of Korea (Korea, Republic of); Lee, Kangtaek [Department of Chemical and Biomolecular Engineering, Yonsei University (Korea, Republic of)

2016-01-15

Molybdenum disulfide (MoS{sub 2}) belongs to transition-metal dichalcogenides (TMDs) family and has vital position among 2D materials. Here, an efficient strategy for the synthesis of zero-dimensional MoS{sub 2} quantum dots (QDs) has been represented. This strategy consists of wet grinding of pristine MoS{sub 2} in N-methyl-2-pyrrolidone (NMP) followed by sonication in NMP and 1,2-dichlorobenzene (o-DCB). The efficacy of this approach to synthesize MoS{sub 2} QDs has been reported by analyzing the as synthesized MoS{sub 2} QDs by different characterization techniques such as high resolution transmission electron microscopy, energy dispersive x-ray spectroscopy, Raman spectroscopy, photoluminescence spectroscopy, Fourier transform infrared spectroscopy and UV–vis spectroscopy. The concentration (yield) of as synthesized MoS{sub 2} QDs was found to be 7 mg mL{sup −1}. Most of the MoS{sub 2} QDs were measured around 2–5 nm in size. The as synthesized MoS{sub 2} QDs showed distinct blue luminescence upon UV excitation. - Highlights: • Synthesis of MoS{sub 2} quantum dots. • Wet grinding of MoS{sub 2} flakes for 6 h in NMP. • Ultrasonication of MoS{sub 2} in NMP and DCB. • Particle size 2–5 nm and concentration 7 mg/ml. • MoS{sub 2} QDs showed blue luminescence.

Evidence for a pore-filling mechanism in the adsorption of aromatic hydrocarbons to a natural wood char.

Science.gov (United States)

Nguyen, Thanh H; Cho, Hyun-Hee; Poster, Dianne L; Ball, William P

2007-02-15

Sorption isotherms for five aromatic hydrocarbons were obtained with a natural wood char (NC1) and its residue after solvent extraction (ENC1). Substantial isotherm nonlinearity was observed in all cases. ENC1 showed higher BET surface area, higher nitrogen-accessible micropore volume, and lower mass of extractable organic chemicals, including quantifiable polycyclic aromatic hydrocarbons (PAHs),while the two chars showed identical surface oxygen/ carbon (O/C) ratio. For two chlorinated benzenes that normally condense as liquids at the temperatures used, sorption isotherms with NC1 and ENC1 were found to be statistically identical. For the solid-phase compounds (1,4-dichlorobenzene (1,4-DCB) and two PAHs), sorption was statistically higher with ENC1, thus demonstrating sorption effects due to both (1) authigenic organic content in the sorbentand (2)the sorbate's condensed state. Polanyi-based isotherm modeling, pore size measurements, and comparisons with activated carbon showthe relative importance of adsorptive pore filling and help explain results. With both chars, maximum sorption increased in the order of decreasing molecular diameter: phenanthrene < naphthalene < 1,2-dichlorobenzene/1,2,4-trichlorobenzene < 1,4-DCB. Comparison of 1,4- and 1,2-DCB shows that the critical molecular diameter was apparently more important than the condensed state, suggesting that 1,4-DCB sorbed in the liquid state for ENC1.

Removal of Malachite Green from aqueous solution using degreased coffee bean.

Science.gov (United States)

Baek, Mi-Hwa; Ijagbemi, Christianah Olakitan; O, Se-Jin; Kim, Dong-Su

2010-04-15

This study reports on the feasibility of employing degreased coffee beans (DCB) as adsorbent for Malachite Green (MG) removal in dyeing wastewater. The iodine value (IV), specific surface area (SSA) and porosity of the raw coffee beans (RCB) used in the study increased after the degreasing process, resulting in significant increase in the adsorption of MG onto DCB. Employing a batch experimental set-up, optimum conditions for complete color removal and adsorption of MG by DCB was studied considering parameters such as effect of degreasing process, adsorbent dosage, initial dye concentration, reaction temperature and pH. Adsorbed amount of MG by DCB increased with increasing DCB dosage and initial MG concentration. The rate of the adsorption reaction followed the pseudo second-order kinetics with the sorption isotherm well fitted to the Freundlich and the Langmuir isotherm models. Thermodynamic studies revealed that the adsorption processes is spontaneous and endothermic in nature. DCB has potentials for application as adsorbent for the removal of MG from dyeing process wastewater. 2009 Elsevier B.V. All rights reserved.

Preparation and structural characterization of zwitterionic surfactant intercalated into NiZn-layered hydroxide salts

Science.gov (United States)

Liu, Jiexiang; Wang, Jianlong; Zhang, Xiaoguang; Fang, Binbin; Hu, Pan; Zhao, Xuyang

2015-10-01

Three zwitterionic surfactants, dodecyl dimethyl carboxylbetaine (DCB), dodecyl dimethyl sulfobetaine (DSB) and N-dodecyl-β-aminoprpionate (DAP), intercalated into NiZn-layered hydroxide salts (NZL-DCB, NZL-DSB and NZL-DAP) were synthesized by the coprecipitation method. The effect of surfactant content, pH, temperature and time of hydrothermal treatment on preparation was investigated and discussed. The NZL-DCB, NZL-DSB and NZL-DAP were characterized by powder X-ray diffraction (PXRD), Fourier transform infrared spectroscopy (FTIR), and thermogravimetry analysis and differential thermal analysis (TGA/DTA). The results showed that basal spacings of NZL-DCB, NZL-DSB and NZL-DAP were around 3.45, 3.68 and 3.94 nm, respectively. DCB, DSB and DAP probably form an overlapped bilayer in the gallery. TGA/DTA data indicated that NZL-DCB, NZL-DSB and NZL-DAP displayed three loss weight stages: loss of adsorbed and structural water, dehydroxylation of matrix and decomposition of nitrate ions, decomposition and combustion of surfactants. Furthermore, chemical analysis data, BET surface area and scanning electron microscopic (SEM) were also measured and analyzed.

Recent developments in the use of 2-alkylcyclobutanones as markers for irradiated lipid-containing foods

International Nuclear Information System (INIS)

Stewart, E.M.; Department of Agriculture for Northern Ireland, Belfast; Moore, S.; Graham, W.D.; McRoberts, W.C.; Hamilton, J.T.G.

1998-01-01

Complete text of publication follows. The use of 2-alkylcyclobutanones as markers for irradiated fat-containing foods has been well documented in the recent years. Initial development of the method concentrated on the detection of 2-dodecylcyclobutanone (2-DCB) in irradiated chicken meat with the methodology being subsequently modified to also detect 2-tetradecylcyclobutanone (2-TCB). The method has been validated by interlaboratory blind trials for chicken meat, pork and liquid whole egg, and was finally adopted as a European Standard (en1785) for the detection of irradiated fat-containing foods by the European Committee for Standardization (CEN) in 1996. Work has continued to further extend the applicability of this irradiation detection test to other fat-containing foods. Experimental work has shown that 2-DCB and 2-TCB can be used as markers for irradiated salmon meat, Camembert cheese, mango and papaya. The effects of irradiation dose and storage on the cyclobutanone concentration of Camembert cheese, mango and papaya have been studied while the effects of dose and temperature of irradiation were investigated for salmon meat. Other recent studies have included the investigation of the supercritical fluid extraction (SFE) technique as an alternative means of fat extraction from irradiated foods and, in addition, for extraction of the cyclobutanones directly from samples. Work is also progressing on the development of an enzyme-linked immunosorbent assay (ELISA) for the detection of cyclobutanones with the view to developing a rapid screening test for irradiated fat-containing foods

Characterization of Mode 1 and Mode 2 delamination growth and thresholds in graphite/peek composites

Science.gov (United States)

Martin, Roderick H.; Murri, Gretchen B.

1988-01-01

Composite materials often fail by delamination. The onset and growth of delamination in AS4/PEEK, a tough thermoplastic matrix composite, was characterized for mode 1 and mode 2 loadings, using the Double Cantilever Beam (DCB) and the End Notched Flexure (ENF) test specimens. Delamination growth per fatigue cycle, da/dN, was related to strain energy release rate, G, by means of a power law. However, the exponents of these power laws were too large for them to be adequately used as a life prediction tool. A small error in the estimated applied loads could lead to large errors in the delamination growth rates. Hence strain energy release rate thresholds, G sub th, below which no delamination would occur were also measured. Mode 1 and 2 threshold G values for no delamination growth were found by monitoring the number of cycles to delamination onset in the DCB and ENF specimens. The maximum applied G for which no delamination growth had occurred until at least 1,000,000 cycles was considered the threshold strain energy release rate. Comments are given on how testing effects, facial interference or delamination front damage, may invalidate the experimental determination of the constants in the expression.

Estimation and analysis of the short-term variations of multi-GNSS receiver differential code biases using global ionosphere maps

Science.gov (United States)

Li, Min; Yuan, Yunbin; Wang, Ningbo; Liu, Teng; Chen, Yongchang

2017-12-01

Care should be taken to minimize the adverse impact of differential code biases (DCBs) on global navigation satellite systems (GNSS)-derived ionospheric information determinations. For the sake of convenience, satellite and receiver DCB products provided by the International GNSS Service (IGS) are treated as constants over a period of 24 h (Li et al. (2014)). However, if DCB estimates show remarkable intra-day variability, the DCBs estimated as constants over 1-day period will partially account for ionospheric modeling error; in this case DCBs will be required to be estimated over shorter time period. Therefore, it is important to further gain insight into the short-term variation characteristics of receiver DCBs. In this contribution, the IGS combined global ionospheric maps and the German Aerospace Center (DLR)-provided satellite DCBs are used in the improved method to determine the multi-GNSS receiver DCBs with an hourly time resolution. The intra-day stability of the receiver DCBs is thereby analyzed in detail. Based on 1 month of data collected within the multi-GNSS experiment of the IGS, a good agreement within the receiver DCBs is found between the resulting receiver DCB estimates and multi-GNSS DCB products from the DLR at a level of 0.24 ns for GPS, 0.28 ns for GLONASS, 0.28 ns for BDS, and 0.30 ns for Galileo. Although most of the receiver DCBs are relatively stable over a 1-day period, large fluctuations (more than 9 ns between two consecutive hours) within the receiver DCBs can be found. We also demonstrate the impact of the significant short-term variations in receiver DCBs on the extraction of ionospheric total electron content (TEC), at a level of 12.96 TECu (TEC unit). Compared to daily receiver DCB estimates, the hourly DCB estimates obtained from this study can reflect the short-term variations of the DCB estimates more dedicatedly. The main conclusion is that preliminary analysis of characteristics of receiver DCB variations over short

Avaliação de procedimentos de extração dos óxidos de ferro pedogênicos com ditionito-citrato-bicarbonato de sódio Evaluation of pedogenic iron oxide extraction procedures with sodium dithionite-citrate-bicarbonate

Directory of Open Access Journals (Sweden)

A. V. Inda Junior

2003-12-01

Full Text Available Em 20 amostras hematíticas e goethíticas de horizontes B latossólicos, uma de B plíntico, uma de B incipiente e uma de saprolito, foram avaliados dois procedimentos de extração de óxidos de ferro pedogênicos (Fe d por ditionito-citrato-bicarbonato de sódio (DCB. O procedimento a 80 ºC (DCB80 extraiu aproximadamente 90 % do Fe d na primeira extração e praticamente a totalidade do mesmo na segunda extração, sendo mais efetivo que o procedimento a temperatura ambiente (DCB20, o qual teve sua eficiência reduzida com o aumento da substituição isomórfica de Fe3+ por Al3+ na goethita. A substituição isomórfica de Fe3+ por Al3+ na goethita determinada por DCB80 superestimou os valores determinados por DRX conforme aumentaram as extrações. Em amostras hematíticas, esta estimativa foi prejudicada pela presença de maghemita que dissolveu juntamente com a hematita.Pedogenic iron oxides (Fe d were quantified in 22 hematitic and goethitic soil samples (19 from oxic horizons; one from a plinthic horizon; one from a cambic horizon; one from saprolite by use of two extraction procedures with sodium dithionite-citrate-bicarbonate (DCB. Approximately ninety percent of the Fe d content was extracted at the first extraction by the DCB80 procedure. This procedure was more effective at extracting Fe d than the DCB20, whose efficiency decreased with increasing Al3+-substitution in goethite. Compared with the DRX analysis, Al3+-substitution in goethite determined by the DCB80 procedure was superestimated. Maghemite masked Al3+-substitution estimates in hematite from hematitic samples.

Performance evaluation of the European Committee Standardization Method EN1785 for the detection of irradiated processed food

International Nuclear Information System (INIS)

Tsutsumi, Tomoaki; Adachi, Rika; Takatsuki, Satoshi; Matsuda, Rieko; Teshima, Reiko; Nei, Daisuke; Kameya, Hiromi; Todoriki, Setsuko; Kikuchi, Masahiro; Kobayashi, Yasuhiko

2014-01-01

2-dodecylcyclobutanone (DCB) and 2-tetradecylcyclobutanone (TCB) are specific radiolytic products in irradiated lipid-containing food and can be used to detect irradiated foods. We previously reported a performance evaluation test in a single laboratory for qualitative detection methods using DCB and TCB as markers for irradiated foods. EN1785, a European Committee Standardization Method, has been widely used for qualitative detection of DCB and TCB in irradiated foods. Here, we evaluated the applicability of EN1785 to camembert cheese, liquid whole egg, sausage and eel grilled without seasoning by using our evaluation test. In this test, extracted lipids from the food were used as negative samples. The lipids spiked with DCB and TCB were used as positive samples. For each food type, 4 negative and 16 positive samples were analyzed by EN1785. All of the negative samples were judged negative and all of the positive samples were judged positive. Thus, EN1785 should be able to detect irradiation in the tested food. Additionally, to confirm the ability of the validated method to detect irradiated food, the same type of food examined above, both unirradiated and irradiated at doses of 0.5-4 kGy, were analyzed by the method. All of the unirradiated samples were judged negative and all of the irradiated samples were judged positive. (author)

Anaerobic bacteria that dechlorinate perchloroethene.

Science.gov (United States)

Fathepure, B Z; Nengu, J P; Boyd, S A

1987-01-01

In this study, we identified specific cultures of anaerobic bacteria that dechlorinate perchlorethene (PCE). The bacteria that significantly dechlorinated PCE were strain DCB-1, an obligate anaerobe previously shown to dechlorinate chlorobenzoate, and two strains of Methanosarcina. The rate of PCE dechlorination by DCB-1 compared favorably with reported rates of trichloroethene bio-oxidation by methanotrophs. Even higher PCE dechlorination rates were achieved when DCB-1 was grown in a methanogenic consortium. PMID:3426224

A critical review on toxicological safety of 2-alkylcyclobutanones

International Nuclear Information System (INIS)

Song, Beom-Seok; Choi, Soo-Jeong; Jin, Young-Bae; Park, Jong-Heum; Kim, Jae-Kyung; Byun, Eui-Baek; Kim, Jae-Hun; Lee, Ju-Woon; Kim, Gang-Sung; Marchioni, Eric

2014-01-01

2-Alkylcyclobutanones (2-ACBs) are known as unique radiolytic products generated from the major fatty acids and triglycerides in food through only irradiation. Since 1990, studies on the toxicological safety of 2-ACBs have been conducted extensively with synthetic compounds. Mutagenicity tests of 2-ACBs on the microorganisms reviewed in this study clearly indicate that no evidence was observed, while several in vitro studies demonstrated the cytotoxicity of 2-ACBs through cell death. Moreover, the genotoxicity of 2-ACBs was suggested as DNA strand breaks were observed. However, these findings should be interpreted with caution because genotoxicity may result from cytotoxicity, which causes DNA damage or from cell membrane destruction and indirect oxidative DNA damage. Therefore, elucidation of the mechanism of genotoxic effects is needed. With regards to the suggestion of Raul et al. (2002) who showed the promoting effect of colon cancer by the administration of 2-ACBs, further studies are needed to correct some experimental design errors. Moreover, an in-vivo experiment that evaluated the metabolism of 2-ACBs has revealed that 2-dDCB was metabolized into cyclic alcohol and excreted through fecal discharge. In conclusion, it is considered that the ingestion of 2-ACBs through irradiated foods is unlikely to affect the human health. However, more specific studies are required to identify the fate of 2-ACBs in body and the LD 50 values. The determination of chronic toxicity by long-term exposure to low concentrations of 2-ACBs has to be evaluated more clearly to determine if these compounds are safe to human. - Highlights: • Mutagenicity 2-ACBs on the microorganisms was not observed. • Several in vitro studies demonstrated the cytotoxicity of 2-ACBs. • Genotoxicity of 2-ACBs was suggested, but elucidation of the mechanism is needed. • 2-dDCB was metabolized into cyclic alcohol and excreted in feces. • Further studies for toxicity of 2-ACBs following

Delamination R-curve as a material property of unidirectional glass/epoxy composites

International Nuclear Information System (INIS)

Shokrieh, M.M.; Heidari-Rarani, M.; Ayatollahi, M.R.

2012-01-01

Highlights: → The R-curve behavior of a unidirectional laminate as a material property is investigated. → Effect of initial crack length and thickness on R-curve is experimentally shown. → A mathematical relation is proposed to model the R-curve behavior of any unidirectional laminated composite. -- Abstract: It is still questionable to think of delamination resistance of a double cantilever beam (DCB) as a material property independent of the specimen size and geometry. In this research, the effects of initial crack length and DCB specimen thickness on the mode I delamination resistance curve (R-curve) behavior of different unidirectional glass/epoxy DCB specimens are experimentally investigated. It is observed that the magnitudes of initiation and propagation delamination toughness (G Ic-init and G Ic-prop ) as well as the fiber bridging length are constant in a specific range of the initial crack length to the DCB specimen thickness ratios of 8.5 0 /h < 19. Finally, a mathematical relationship is proposed for prediction of mode I delamination behavior (from the initiation to propagation) of E-glass/epoxy DCB specimens.

Dichlorobenzene: an effective solvent for epoxy/graphene nanocomposites preparation.

Science.gov (United States)

Wei, Jiacheng; Saharudin, Mohd Shahneel; Vo, Thuc; Inam, Fawad

2017-10-01

It is generally recognized that dimethylformamide (DMF) and ethanol are good media to uniformly disperse graphene, and therefore have been used widely in the preparation of epoxy/graphene nanocomposites. However, as a solvent to disperse graphene, dichlorobenzene (DCB) has not been fully realized by the polymer community. Owing to high values of the dispersion component ( δ d ) of the Hildebrand solubility parameter, DCB is considered as a suitable solvent for homogeneous graphene dispersion. Therefore, epoxy/graphene nanocomposites have been prepared for the first time with DCB as a dispersant; DMF and ethanol have been chosen as the reference. The colloidal stability, mechanical properties, thermogravimetric analysis, dynamic mechanical analysis and scanning electron microscopic images of nanocomposites have been obtained. The results show that with the use of DCB, the tensile strength of graphene has been improved from 64.46 to 69.32 MPa, and its flexural strength has been increased from 97.17 to 104.77 MPa. DCB is found to be more effective than DMF and ethanol for making stable and homogeneous graphene dispersion and composites.

A two-step ionospheric modeling algorithm considering the impact of GLONASS pseudo-range inter-channel biases

Science.gov (United States)

Zhang, Rui; Yao, Yi-bin; Hu, Yue-ming; Song, Wei-wei

2017-12-01

The Global Navigation Satellite System presents a plausible and cost-effective way of computing the total electron content (TEC). But TEC estimated value could be seriously affected by the differential code biases (DCB) of frequency-dependent satellites and receivers. Unlike GPS and other satellite systems, GLONASS adopts a frequency-division multiplexing access mode to distinguish different satellites. This strategy leads to different wavelengths and inter-frequency biases (IFBs) for both pseudo-range and carrier phase observations, whose impacts are rarely considered in ionospheric modeling. We obtained observations from four groups of co-stations to analyze the characteristics of the GLONASS receiver P1P2 pseudo-range IFB with a double-difference method. The results showed that the GLONASS P1P2 pseudo-range IFB remained stable for a period of time and could catch up to several meters, which cannot be absorbed by the receiver DCB during ionospheric modeling. Given the characteristics of the GLONASS P1P2 pseudo-range IFB, we proposed a two-step ionosphere modeling method with the priori IFB information. The experimental analysis showed that the new algorithm can effectively eliminate the adverse effects on ionospheric model and hardware delay parameters estimation in different space environments. During high solar activity period, compared to the traditional GPS + GLONASS modeling algorithm, the absolute average deviation of TEC decreased from 2.17 to 2.07 TECu (TEC unit); simultaneously, the average RMS of GPS satellite DCB decreased from 0.225 to 0.219 ns, and the average deviation of GLONASS satellite DCB decreased from 0.253 to 0.113 ns with a great improvement in over 55%.

Sequestration of maize crop straw C in different soils: role of oxyhydrates in chemical binding and stabilization as recalcitrance.

Science.gov (United States)

Song, Xiangyun; Li, Lianqing; Zheng, Jufeng; Pan, Genxing; Zhang, Xuhui; Zheng, Jinwei; Hussain, Qaiser; Han, Xiaojun; Yu, Xinyan

2012-05-01

While biophysical controls on the sequestration capacity of soils have been well addressed with physical protection, chemical binding and stabilization processes as well as microbial community changes, the role of chemical binding and stabilization has not yet well characterized for soil organic carbon (SOC) sequestration in rice paddies. In this study, a 6-month laboratory incubation with and without maize straw amendment (MSA) was conducted using topsoil samples from soils with different clay mineralogy and free oxy-hydrate contents collected across Southern China. The increase in SOC under MSA was found coincident with that in Fe- and Al-bound OC (Fe/Al-OC) after incubation for 30 d (R(2)=0.90, P=0.05), and with sodium dithionate-citrate-bicarbonate (DCB) extractable Fe after incubation for 180 d (R(2)=0.99, Psoils rich in DCB extractable Fe than those poor in DCB extractable Fe. The greater SOC sequestration in soils rich in DCB extractable Fe was further supported by the higher abundance of (13)C which was a natural signature of MSA. Moreover, a weak positive correlation of the increased SOC under MSA with the increased humin (R(2)=0.87, P=0.06) observed after incubation for 180 d may indicate a chemical stabilization of sequestered SOC as humin in the long run. These results improved our understanding of SOC sequestration in China's rice paddies that involves an initial chemical binding of amended C and a final stabilization as recalcitrant C of humin. Copyright © 2012 Elsevier Ltd. All rights reserved.

Structural Insights into Arl1-Mediated Targeting of the Arf-GEF BIG1 to the trans-Golgi

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Antonio Galindo

2016-07-01

Full Text Available The GTPase Arf1 is the major regulator of vesicle traffic at both the cis- and trans-Golgi. Arf1 is activated at the cis-Golgi by the guanine nucleotide exchange factor (GEF GBF1 and at the trans-Golgi by the related GEF BIG1 or its paralog, BIG2. The trans-Golgi-specific targeting of BIG1 and BIG2 depends on the Arf-like GTPase Arl1. We find that Arl1 binds to the dimerization and cyclophilin binding (DCB domain in BIG1 and report a crystal structure of human Arl1 bound to this domain. Residues in the DCB domain that bind Arl1 are required for BIG1 to locate to the Golgi in vivo. DCB domain-binding residues in Arl1 have a distinct conformation from those in known Arl1-effector complexes, and this plasticity allows Arl1 to interact with different effectors of unrelated structure. The findings provide structural insight into how Arf1 GEFs, and hence active Arf1, achieve their correct subcellular distribution.

Bimolecular Excited-State Electron Transfer with Surprisingly Long-Lived Radical Ions

KAUST Repository

Alsam, Amani Abdu; Aly, Shawkat Mohammede; Usman, Anwar; Parida, Manas R.; Del Gobbo, Silvano; Alarousu, Erkki; Mohammed, Omar F.

2015-01-01

We explored the excited-state interactions of bimolecular, non-covalent systems consisting of cationic poly[(9,9-di(3,3’-N,N’-trimethyl-ammonium) propyl fluorenyl-2,7-diyl)-alt-co-(9,9-dioctyl-fluorenyl-2,7-diyl)] diiodide salt (PFN) and 1,4-dicyanobenzene (DCB) using steady-state and time-resolved techniques, including femto- and nanosecond transient absorption and femtosecond infrared spectroscopies with broadband capabilities. The experimental results demonstrated that photo-induced electron transfer from PFN to DCB occurs on the picosecond time scale, leading to the formation of PFN+• and DCB-• radical ions. Interestingly, real-time observations of the vibrational marker modes on the acceptor side provided direct evidence and insight into the electron transfer process indirectly inferred from UV-Vis experiments. The band narrowing on the picosecond time scale observed on the antisymmetric C-N stretching vibration of the DCB radical anion provides clear experimental evidence that a substantial part of the excess energy is channeled into vibrational modes of the electron transfer product and that the geminate ion pairs dissociate. More importantly, our nanosecond time-resolved data indicate that the charge-separated state is very long lived ( 30 ns) due to the dissociation of the contact radical ion pair into free ions. Finally, the fast electron transfer and slow charge recombination anticipate the current donor−acceptor system with potential applications in organic solar cells.

Bimolecular Excited-State Electron Transfer with Surprisingly Long-Lived Radical Ions

KAUST Repository

Alsam, Amani Abdu

2015-09-02

We explored the excited-state interactions of bimolecular, non-covalent systems consisting of cationic poly[(9,9-di(3,3’-N,N’-trimethyl-ammonium) propyl fluorenyl-2,7-diyl)-alt-co-(9,9-dioctyl-fluorenyl-2,7-diyl)] diiodide salt (PFN) and 1,4-dicyanobenzene (DCB) using steady-state and time-resolved techniques, including femto- and nanosecond transient absorption and femtosecond infrared spectroscopies with broadband capabilities. The experimental results demonstrated that photo-induced electron transfer from PFN to DCB occurs on the picosecond time scale, leading to the formation of PFN+• and DCB-• radical ions. Interestingly, real-time observations of the vibrational marker modes on the acceptor side provided direct evidence and insight into the electron transfer process indirectly inferred from UV-Vis experiments. The band narrowing on the picosecond time scale observed on the antisymmetric C-N stretching vibration of the DCB radical anion provides clear experimental evidence that a substantial part of the excess energy is channeled into vibrational modes of the electron transfer product and that the geminate ion pairs dissociate. More importantly, our nanosecond time-resolved data indicate that the charge-separated state is very long lived ( 30 ns) due to the dissociation of the contact radical ion pair into free ions. Finally, the fast electron transfer and slow charge recombination anticipate the current donor−acceptor system with potential applications in organic solar cells.

Podocyte hypertrophy precedes apoptosis under experimental diabetic conditions.

Science.gov (United States)

Lee, Sun Ha; Moon, Sung Jin; Paeng, Jisun; Kang, Hye-Young; Nam, Bo Young; Kim, Seonghun; Kim, Chan Ho; Lee, Mi Jung; Oh, Hyung Jung; Park, Jung Tak; Han, Seung Hyeok; Yoo, Tae-Hyun; Kang, Shin-Wook

2015-08-01

Podocyte hypertrophy and apoptosis are two hallmarks of diabetic glomeruli, but the sequence in which these processes occur remains a matter of debate. Here we investigated the effects of inhibiting hypertrophy on apoptosis, and vice versa, in both podocytes and glomeruli, under diabetic conditions. Hypertrophy and apoptosis were inhibited using an epidermal growth factor receptor inhibitor (PKI 166) and a pan-caspase inhibitor (zAsp-DCB), respectively. We observed significant increases in the protein expression of p27, p21, phospho-eukaryotic elongation factor 4E-binding protein 1, and phospho-p70 S6 ribosomal protein kinase, in both cultured podocytes exposed to high-glucose (HG) medium, and streptozotocin-induced diabetes mellitus (DM) rat glomeruli. These increases were significantly inhibited by PKI 166, but not by zAsp-DCB. In addition, the amount of protein per cell, the relative cell size, and the glomerular volume were all significantly increased under diabetic conditions, and these changes were also blocked by treatment with PKI 166, but not zAsp-DCB. Increased protein expression of cleaved caspase-3 and cleaved poly (ADP-ribose) polymerase, together with increased Bax/Bcl-2 ratios, were also observed in HG-stimulated podocytes and DM glomeruli. Treatment with either zAsp-DCB or PKI 166 resulted in a significant attenuation of these effects. Both PKI 166 and zAsp-DCB also inhibited the increase in number of apoptotic cells, as assessed by Hoechst 33342 staining and TUNEL assay. Under diabetic conditions, inhibition of podocyte hypertrophy results in attenuated apoptosis, whereas blocking apoptosis has no effect on podocyte hypertrophy, suggesting that podocyte hypertrophy precedes apoptosis.

Critical experiments, measurements and analyses to establish a crack arrest methodology for nuclear pressure vessel steels. First annual progress report

International Nuclear Information System (INIS)

Hahn, G.T.; Gehlen, P.C.; Hoagland, R.G.; Kanninen, M.F.; Popelar, C.; Rosenfield, A.R.; deCampos, V.S.

1975-08-01

The one-dimensional, Timoshenko beam-on-a-generalized elastic foundation treatment has been extended to contoured-DCB specimens and to the conditions attending tensile loading in an ordinary testing machine. Preliminary calculations show that the crack propagation and arrest events in contoured DCB specimens are very similar to those calculated for regular DCB-specimens for comparable initiation conditions. In both cases the calculated K/sub Ia/-values are between 44 and 100 percent of K/sub ID,min/ and show a systematic variation with the initiation K/sub Q/-level. In contrast with stiff wedge loading, which favors a continuous event, the calculations for rectangular and contoured DCB specimens in series with an idealized testing machine load train display one or more halts and restarts before the final arrest. A series of experiments designed to distinguish between the K/sub D/ and K/sub a/ approaches to predicting crack arrest are described. Studies of the effect of side grooves in rectangular DCB specimens confirm that grooves with depths representing up to 60 percent of the cross section have no significant effect on either K/sub ID/ or K/sub Ia/ measurements. (auth)

Photodegradation of Selected PCBs in the Presence of Nano-TiO2 as Catalyst and H2O2 as an Oxidant

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Hongtao Yu

2010-11-01

Full Text Available Photodegradation of five strategically selected PCBs was carried out in acetonitrile/water 80:20. Quantum chemical calculations reveal that PCBs without any chlorine on ortho-positions are closer to be planar, while PCBs with at least one chlorine atoms at the ortho-positions causes the two benzene rings to be nearly perpendicular. Light-induced degradation of planar PCBs is much slower than the perpendicular ones. The use of nano-TiO2 speeds up the degradation of the planar PCBs, but slows down the degradation of the non-planar ones. The use of H2O2 speeds up the degradation of planar PCBs greatly (by >20 times, but has little effect on non-planar ones except 2,3,5,6-TCB. The relative photodegradation rate is: 2,2’,4,4’-TCB > 2,3,5,6-TCB > 2,6-DCB ≈ 3,3’,4,4’-TCB > 3,4’,5-TCB. The use of H2O2 in combination with sunlight irradiation could be an efficient and “green” technology for PCB remediation.

On stochastic modeling of the modernized global positioning system (GPS) L2C signal

International Nuclear Information System (INIS)

Elsobeiey, Mohamed; El-Rabbany, Ahmed

2010-01-01

In order to take full advantage of the modernized GPS L2C signal, it is essential that its stochastic characteristics and code bias be rigorously determined. In this paper, long sessions of GPS measurements are used to study the stochastic characteristics of the modernized GPS L2C signal. As a byproduct, the stochastic characteristics of the legacy GPS signals, namely C/A and P2 codes, are also determined, which are used to verify the developed stochastic model of the modernized signal. The differential code biases between P2 and C2, DCB P2-C2 , are also estimated using the Bernese GPS software. It is shown that the developed models improved the precise point positioning (PPP) solution and convergence time

A Mechanism for the induction of renal tumours in male Fischer 344 rats by short-chain chlorinated paraffins.

Science.gov (United States)

Warnasuriya, Gayathri D; Elcombe, Barbara M; Foster, John R; Elcombe, Clifford R

2010-03-01

Short-chain chlorinated paraffins (SCCPs) cause kidney tumours in male rats, but not in female rats or mice of either sex. Male rat-specific tumours also occur in rats dosed with a range of compounds including 1,4- dichlorobenzene (DCB) and d-limonene (DL). These compounds bind to a male rat-specific hepatic protein, alpha-2-urinary globulin (α2u), and form degradationresistant complexes in the kidney. The resulting accumulation of α2u causes cell death and sustained regenerative cell proliferation, which in turn leads to the formation of renal tumours. To investigate whether the SCCP, Chlorowax 500C (C500C), causes tumours via the accumulation of α2u male rats were orally dosed with either C500C (625 mg/kg of body weight), DCB (300 mg/kg of body weight), or DL (150 mg/kg of body weight) for 28 consecutive days. An increase in renal α2u and cell proliferation was observed in DCB- and DL-treated rats but not in C500C-treated rats. C500C caused peroxisome proliferation and a down-regulation of α2u synthesis in male rat liver. This down-regulation occurred at the transcriptional level. Since less α2u was produced in C500C-treated rats, there was less available for accumulation in the kidney hence a typical α2u nephropathy did not appear. However, the administration of a radiolabelled SCCP, [14C]polychlorotridecane (PCTD), to male rats demonstrated its binding to renal α2u. Thus, it is possible that SCCPs bind to α2u and cause a slow accumulation of the protein in the kidney followed by delayed onset of α2u nephropathy. As a consequence of these findings in the current experiments, while evidence exists implicating α2u-globulin in the molecular mechanism of action of the C500C, the classic profile of a α2u-globulin nephropathy seen with other chemicals such as DCB and DL was not reproduced during this experimental protocol.

Auditory-visual integration in fields of the auditory cortex.

Science.gov (United States)

Kubota, Michinori; Sugimoto, Shunji; Hosokawa, Yutaka; Ojima, Hisayuki; Horikawa, Junsei

2017-03-01

While multimodal interactions have been known to exist in the early sensory cortices, the response properties and spatiotemporal organization of these interactions are poorly understood. To elucidate the characteristics of multimodal sensory interactions in the cerebral cortex, neuronal responses to visual stimuli with or without auditory stimuli were investigated in core and belt fields of guinea pig auditory cortex using real-time optical imaging with a voltage-sensitive dye. On average, visual responses consisted of short excitation followed by long inhibition. Although visual responses were observed in core and belt fields, there were regional and temporal differences in responses. The most salient visual responses were observed in the caudal belt fields, especially posterior (P) and dorsocaudal belt (DCB) fields. Visual responses emerged first in fields P and DCB and then spread rostroventrally to core and ventrocaudal belt (VCB) fields. Absolute values of positive and negative peak amplitudes of visual responses were both larger in fields P and DCB than in core and VCB fields. When combined visual and auditory stimuli were applied, fields P and DCB were more inhibited than core and VCB fields beginning approximately 110 ms after stimuli. Correspondingly, differences between responses to auditory stimuli alone and combined audiovisual stimuli became larger in fields P and DCB than in core and VCB fields after approximately 110 ms after stimuli. These data indicate that visual influences are most salient in fields P and DCB, which manifest mainly as inhibition, and that they enhance differences in auditory responses among fields. Copyright © 2017 Elsevier B.V. All rights reserved.

Interlaminar fracture in woven carbon/epoxy laminates

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Paulo N.B. Reis

2014-10-01

Full Text Available This paper describes an experimental study developed to characterize the mode I and mode II fracture toughness of carbon/epoxy woven composites, using DCB and ENF tests, respectively. The laminates were manufactured using an epoxy resin and twelve woven balanced bi-directional layers of carbon fibres, all of them with the same orientation (0/90º. Significant instantaneous delaminations were observed particularly for the DCB specimen, which were responsible for an oscillatory behaviour of GI versus crack length. The maximum values obtained for GIC and GIIC were 281 and 1800 J/m2, respectively.

Cellulose synthesis inhibition, cell expansion, and patterns of cell wall deposition in Nitella internodes

International Nuclear Information System (INIS)

Richmond, P.A.; Metraux, J.P.

1984-01-01

The authors have investigated the pattern of wall deposition and maturation and correlated it with cell expansion and cellulose biosynthesis. The herbicide 2,6-dichlorobenzonitrile (DCB) was found to be a potent inhibitor of cellulose synthesis, but not of cell expansion in Nitella internodal cells. Although cellulose synthesis is inhibited during DCB treatment, matrix substances continue to be synthesized and deposited. The inhibition of cellulose microfibril deposition can be demonstrated by various techniques. These results demonstrate that matrix deposition is by apposition, not by intussusception, and that the previously deposited wall moves progressively outward while stretching and thinning as a result of cell expansion

Comparison of Intralaminar and Interlaminar Mode-I Fracture Toughness of Unidirectional IM7/8552 Graphite/Epoxy Composite

Science.gov (United States)

Czabaj, Michael W.; Ratcliffe, James

2012-01-01

The intralaminar and interlaminar mode-I fracture-toughness of a unidirectional IM7/8552 graphite/epoxy composite were measured using compact tension (CT) and double cantilever beam (DCB) test specimens, respectively. Two starter crack geometries were considered for both the CT and DCB specimen configurations. In the first case, starter cracks were produced by 12.5 micron thick, Teflon film inserts. In the second case, considerably sharper starter cracks were produced by fatigue precracking. For each specimen configuration, use of the Teflon film starter cracks resulted in initially unstable crack growth and artificially high initiation fracture-toughness values. Conversely, specimens with fatigue precracks exhibited stable growth onset and lower initiation fracture toughness. For CT and DCB specimens with fatigue precracks, the intralaminar and interlaminar initiation fracture toughnesses were approximately equal. However, during propagation, the CT specimens exhibited more extensive fiber bridging, and rapidly increasing R-curve behavior as compared to the DCB specimens. Observations of initiation and propagation of intralaminar and interlaminar fracture, and the measurements of fracture toughness, were supported by fractographic analysis using scanning electron microscopy.

Donor/Acceptor Molecular Orientation-Dependent Photovoltaic Performance in All-Polymer Solar Cells.

Science.gov (United States)

Zhou, Ke; Zhang, Rui; Liu, Jiangang; Li, Mingguang; Yu, Xinhong; Xing, Rubo; Han, Yanchun

2015-11-18

The correlated donor/acceptor (D/A) molecular orientation plays a crucial role in solution-processed all-polymer solar cells in term of photovoltaic performance. For the conjugated polymers PTB7-th and P(NDI2OD-T2), the preferential molecular orientation of neat PTB7-th films kept face-on regardless of the properties of processing solvents. However, an increasing content of face-on molecular orientation in the neat P(NDI2OD-T2) films could be found by changing processing solvents from chloronaphthalene (CN) and o-dichlorobenzene (oDCB) to chlorobenzene (CB). Besides, the neat P(NDI2OD-T2) films also exhibited a transformation of preferential molecular orientation from face-on to edge-on when extending film drying time by casting in the same solution. Consequently, a distribution diagram of molecular orientation for P(NDI2OD-T2) films was depicted and the same trend could be observed for the PTB7-th/P(NDI2OD-T2) blend films. By manufacture of photovoltaic devices with blend films, the relationship between the correlated D/A molecular orientation and device performance was established. The short-circuit current (Jsc) of devices processed by CN, oDCB, and CB enhanced gradually from 1.24 to 8.86 mA/cm(2) with the correlated D/A molecular orientation changing from face-on/edge-on to face-on/face-on, which could be attributed to facile exciton dissociation at D/A interface with the same molecular orientation. Therefore, the power conversion efficiency (PCE) of devices processed by CN, oDCB, and CB improved from 0.53% to 3.52% ultimately.

Chemical composition of elephant grass silages supplemented with different levels of dehydrated cashew bagasse

Directory of Open Access Journals (Sweden)

Danillo Glaydson Farias Guerra

2016-04-01

Full Text Available The objective of the present study was to evaluate the chemical composition of elephant grass silages supplemented with different levels dried cashew bagasse (DCB. Our experiment used a randomized design replicated four times, each replicate consisting of the following five treatments: 100% elephant grass; 95% elephant grass + 5% DCB; 90% elephant grass + 10% DCB; 85% elephant grass + 15% DCB; and 80% elephant grass + 20% DCB. The elephant grass was cut manually to a residual height of 5 cm at 80 days of age, and cashew bagasse was obtained from the processing of cashew stalks used in fruit pulp manufacturing in Mossoró/RN. Plastic buckets were used as experimental silos, and 90 days after ensiling the experimental silos were opened and the contents analyzed. The addition of dried cashew bagasse to silage linearly increased the levels of dried matter and crude protein by 0.59% and 0.13%, respectively, for each 1% addition (P < 0.05. The neutral detergent fiber and acid detergent content of the silages was reduced by 0.22% and 0.09%, respectively, for each 1% addition of the bagasse. The total carbohydrate content was not influenced by the bagasse addition (P > 0.05, and averaged 82.29%. The levels of non-fiber carbohydrate showed linear growth (P < 0.05 as the dehydrated cashew bagasse was added, and pH and ammoniacal nitrogen levels were reduced. The addition of the dehydrated bagasse to elephant grass silage improves its chemical composition, and it can be effectively added up to the level of 20%.

ORF Alignment: NC_003902 [GENIUS II[Archive

Lifescience Database Archive (English)

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Lifescience Database Archive (English)

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Lifescience Database Archive (English)

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ORF Alignment: NC_003919 [GENIUS II[Archive

Lifescience Database Archive (English)

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Lifescience Database Archive (English)

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ORF Alignment: NC_006370 [GENIUS II[Archive

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ORF Alignment: NC_003919 [GENIUS II[Archive

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ORF Alignment: NC_006834 [GENIUS II[Archive

Lifescience Database Archive (English)

Full Text Available ative regulator of cell autolysis [Desulfitobacterium ... hafniense DCB-2] ... Length = 127 ... Q... NC_006834 gi|58583632 >1i58A 23 189 289 415 6e-06 ... ref|ZP_00097900.1| COG3275: Put

Crack arrest toughness of structural steels evaluated by compact test

International Nuclear Information System (INIS)

Nakano, Yoshifumi; Tanaka, Michihiro

1982-01-01

Crack arrest tests such as compact, ESSO and DCB tests were made on SA533B Cl. 1, HT80 and KD32 steels to evaluate the crack arrest toughness. The main results obtained are as follows: (1) The crack arrest toughness could be evaluated by K sub(Ia) which was obtained by the static analysis of compact test. (2) K sub(ID) determined by the dynamic analysis of compact test was greater than K sub(Ia), though K sub(ID) became close to K sub(Ia)/K sub(Q) became a unity where K sub(Q) is the stress intensity factor at the crack initiation. (3) No significant difference was observed between K sub(Ia) and K sub(ca) obtained by ESSO and DCB tests, though K sub(ca) obtained by DCB test tended to be smaller than K sub(Ia) at lower temperatures. (4) K sub(Ia) was smaller than K sub(Ic) in the transition temperature range, while it was greater than K sub(Id). In the temperature range where K sub(Ic), which was determined from J sub(Ic), decreased with temperature increase, however, it was smaller than K sub(Ia). (5) The fracture appearance transition temperature and the absorbed energy obtained by 2 mm V-notch Charpy test were appropriate parameters for representing the crack arrest toughness, while the NDT temperature was not. (author)

Class III peroxidases in cellulose deficient cultured maize cells during cell wall remodelling.

Science.gov (United States)

Martínez-Rubio, Romina; Acebes, José Luis; Encina, Antonio; Kärkönen, Anna

2018-02-21

Maize (Zea mays L.) suspension-cultured cells habituated to a cellulose biosynthesis inhibitor 2,6-dichlorobenzonitrile (DCB) have a modified cell wall, in which the reduction in the cellulose content is compensated by a network of highly cross-linked feruloylated arabinoxylans and the deposition of lignin-like polymers. For both arabinoxylan cross-linking and lignin polymerization, class III peroxidases (POXs) have been demonstrated to have a prominent role. For the first time, a comparative study of POX activity and isoforms in control and cellulose-impaired cells has been addressed, also taking into account their cellular distribution in different compartments. Proteins from the spent medium (SM), soluble cellular (SC), ionically (ICW) and covalently bound cell wall protein fractions were assayed for total and specific peroxidase activity by using coniferyl and sinapyl alcohol and ferulic acid as substrates. The isoPOX profile was obtained by isoelectric focusing. POX activity was higher in DCB-habituated than in non-habituated cells in all protein fractions at all cell culture stages. For all substrates assayed, SC and ICW fractions showed higher activity at the early-log growth phase than at the late-log phase. However, the highest POX activity in the spent medium was found at the late-log phase. According to the isoPOX profiles, the highest diversity of isoPOXs was detected in the ICW and SM protein fractions. The latter fraction contained isoPOXs with higher activity in DCB-habituated cells. Some of the isoPOXs detected could be involved in cross-linking of arabinoxylans and in the lignin-like polymer formation in DCB-habituated cells. This article is protected by copyright. All rights reserved.

VASOMOTOR ENDOTHELIAL FUNCTION AND MICROCIRCULATION IN ELDERLY PATIENTS WITH ISOLATED SYSTOLIC ARTERIAL HYPERTENSION: INFLUENCE OF "DRY" CARBONIC BATHS AND GENERAL LOW-FREQUENCY MAGNETOTHERAPY

OpenAIRE

Alypova, Elena

2013-01-01

Abstract. The comparative estimation of influence of the general low-frequency magnetotherapy (GLMT) and "dry" carbonic baths (DCB) on indicators of vasomotor endothelial function and microcirculation in elderly patients with isolated systolic (ISAH) arterial hypertension has been studied. The efficiency of application the combined use of the GLMT and "dry" carbonic baths DCB for correction of revealed disorders in comparing to the monovariant use of thees medical physical factors is establis...

Determination of the distribution and reaction of polysaccharides in wood cell walls by the isotope tracer technique, 6: Selective radio-labeling of mannan in ginkgo (Ginkgo biloba)

International Nuclear Information System (INIS)

Imai, T.; Terashima, N.; Yasuda, S.

1997-01-01

D-Mannose-[2-H-3] and GDP (guanosine diphosphate)-D-mannose-[mannose-1-H-3] were administered to the shoots of ginkgo (Ginkgo biloba L.) tolabel mannan selectively in the cell walls. To suppress the incorporation of radioactivity into the lignin and cellulose, the precursors were administered in the presence of the inhibitor of phenylalanine ammonia-lyase (PAL): namely, L-alpha-aminooxy-beta-phenylpropionic acid (AOPP) and the inhibitor of glucan synthesis: namely, 2-deoxy-D-glucose (2-DG) and 2.6-dichlorobenzonitrile (2.6-DCB). When D-mannose-[2-H-3] was administered in the absence of the inhibitors, great radioactivities were found in the mannose and glucose obtained by sulfuric acid hydrolysis of the newly-formed xylem, and also in the vanillin obtained by nitrobenzene oxidation. These results indicate that the radioactivity was incorporated not only into mannan but also into cellulose and lignin. When D-mannose-[2-H-3] was administered in the presence of both AOPP and 2-DG, the radioactivities of vanillin and glucose were decreased but that of mannose was not decreased. These results indicate that the incorporations of radioactivities into lignin and cellulose were suppressed by the inhibitors, but the incorporation into mannan was not interfered with. The treatment with 2,6-DCB lessened the incorporations of radioactivity into vanillin, xylose, mannose, and glucose of the newly formed xylem considerably which indicated that 2,6-DCB disturbed the metabolic activities of the plant fatally. Consequently, the selective radiolabeling of mannan in ginkgo was achieved by the administration of D-mannose-[2-H-3], in the presence of both AOPP and 2-DG, toa growing stem. In the case of GDP-D-mannose-[mannose-1-H-3], the radioactivity incorporated into the newly-formed xylem was very little, and the selectivity in labeling and the effects of the inhibitors were not clear

Single-molecule conductance with nitrile and amino contacts with Ag or Cu electrodes

International Nuclear Information System (INIS)

Li, Dong-Fang; Mao, Jin-Chuan; Chen, De-Li; Chen, Fang; Ze-Wen, Hong; Zhou, Xiao-Yi; Wang, Ya-Hao; Zhou, Xiao-Shun; Niu, Zhen-Jiang; Maisonhaute, Emmanuel

2015-01-01

The single-molecule conductance of 1,4-dicyanobenzene (DCB), 1,4-benzenediamine (BDA) and 4,4'-biphenyldicarbonitrile (BPDC) with Ag and/or Cu electrodes is measured by electrochemical jump-to-contact STM-break junction. All single-molecule junctions present three sets of conductance values revealing different contact geometries. We observe that the single-molecule conductance of Ag-BDA-Ag junction is larger that of Ag-DCB-Ag junction, and DCB with Ag contacts are more conductive than that with Cu ones. This is related to a different electronic coupling between the molecules and the electrodes. Tunneling decay constants of 1.70 and 1.68 per phenyl group were found for Ag and Cu electrodes, respectively. The present study therefore shows that nitrile and amino groups can also be used as effective anchors for other metals than gold

DCB - DNA and Chromosome Aberrations Research

Science.gov (United States)

Part of NCI's Division of Cancer Biology's research portfolio, this research area is focused on making clear the genetic and epigenetic mechanisms of tumorigenesis and mechanisms of chemical and physical carcinogenesis.

Critical appraisal of paclitaxel balloon angioplasty for femoral–popliteal arterial disease

Directory of Open Access Journals (Sweden)

Herten M

2016-08-01

Full Text Available Monika Herten,1 Giovanni B Torsello,1,2 Eva Schönefeld,3 Stefan Stahlhoff2 1Department of Vascular and Endovascular Surgery, University Hospital Münster, 2Department of Vascular Surgery, St Franziskus Hospital, Münster, 3Institute for Education and Student Affairs, University Hospital Münster, Münster, Germany Abstract: Peripheral arterial disease, particularly critical limb ischemia, is an area with urgent need for optimized therapies because, to date, vascular interventions often have limited life spans. In spite of initial encouraging technical success after femoropopliteal percutaneous transluminal angioplasty or stenting, postprocedural restenosis remains the major problem. The challenging idea behind the drug-coated balloon (DCB concept is the biological modification of the injury response after balloon dilatation. Antiproliferative drugs administered via DCBs or drug-eluting stents are able to suppress neointimal hyperplasia, the main cause of restenosis. This article reviews the results of DCB treatments of femoropopliteal and infrapopliteal lesions in comparison to standard angioplasty with uncoated balloons. A systematic literature search was performed in 1 medical journals (ie, MEDLINE, 2 international registers for clinical studies (ie, www.clinicaltrials.gov, and 3 abstracts of scientific sessions. Several controlled randomized trials with follow-up periods of up to 5 years demonstrated the efficacy of paclitaxel –DCB technology. However, calcified lesions seem to affect the efficacy of DCB. Combinations of preconditioning methods with DCBs showed promising results. Although the mechanical abrasion of calcium via atherectomy or laser ablation showed favorable periprocedural results, the long-term impact on restenosis and clinical outcome has to be demonstrated. Major advantages of the DCBs are the rapid delivery of drug at uniform concentrations with a single dose, their efficacy in areas wherein stents have been

Contaminant mass flow rates between groundwater, streambed sediments and surface water at the regionally contaminated site Bitterfeld; Schadstoffmassenstroeme zwischen Grundwasser, Flussbettsedimenten und Oberflaechenwasser am regional kontaminierten Standort Bitterfeld

Energy Technology Data Exchange (ETDEWEB)

Schmidt, C.; Krieg, R.; Bayer-Raich, M.; Leschik, S. [Helmholtz-Zentrum fuer Umweltforschung GmbH - UFZ, Department Hydrogeologie, Leipzig (Germany); Kalbus, E. [Eberhard-Karls-Universitaet Tuebingen, Zentrum fuer Angewandte Geowissenschaften (ZAG), Tuebingen (Germany); UFZ - Helmholtz-Zentrum fuer Umweltforschung GmbH, Department Umweltinformatik, Leipzig (Germany); Reinstorf, F. [Hochschule Magdeburg-Stendal, Fachbereich Wasser- und Kreislaufwirtschaft, Magdeburg (Germany); Martienssen, M. [Helmholtz-Zentrum fuer Umweltforschung GmbH - UFZ, Department Hydrogeologie, Halle/Saale (Germany); Schirmer, M. [EAWAG, das Wasserforschungs-Institut des ETH-Bereichs, Abteilung Wasserressourcen und Trinkwasser, Duebendorf (Switzerland)

2008-09-15

As a result of intensive industrial, mining, and urban development, numerous large-scale contaminated areas exist in Germany. These so-called megasites represent a challenge to risk assessment and remediation strategies. At the Bitterfeld megasite, the contaminated groundwater interacts with the local streams. Along a stream reach 280 m long, the mass flow rates of chlorinated benzenes were estimated by combining integral pumping tests, streambed temperature mapping, and analyses of contaminant concentrations in the streambed sediments. On average, a total mass flow rate of 617 mg d{sup -1} monochlorobenzene (MCB) and 157 mg d{sup -1} dichlorobenzene (DCB) is released from the adjoining aquifer into the stream along the investigated reach. Further, the streambed sediment acts as the dominant contaminant source. Considering the streambed sediments, the contaminant mass flow rate to the river increases to values between 2,355 and 4,323 mg d{sup -1} MCB and between 892 and 3,587 mg d{sup -1} DCB. (orig.) [German] Als Folge intensiver industrieller, bergbaulicher und urbaner Nutzung gibt es in Deutschland zahlreiche grossflaechig kontaminierte Standorte. Diese so genannten Megasites stellen eine grosse Herausforderung fuer die Risikobewertung und Sanierung dar. An der Megasite Bitterfeld kommt es zudem zu Wechselwirkungen zwischen kontaminiertem Grundwasser und den lokalen Vorflutern. An einem 280 m langen Flussabschnitt wurden durch die Kombination integraler Pumpversuche, Kartierung der Flussbettsedimenttemperaturen und Analysen der Schadstoffkonzentrationen im Flussbettsediment die Schadstoffmassenstroeme chlorierter Benzole abgeschaetzt, die mit der Grundwasserstroemung aus dem Aquifer und dem Flussbettsediment in den Vorfluter gelangen. Im Mittel gelangt am untersuchten Flussabschnitt eine Fracht von 617 mg d{sup -1} Monochlorbenzen (MCB) und 157 mg d{sup -1} Dichlorbenzen (DCB) aus dem Aquifer in den Vorfluter. Das Flussbettsediment des untersuchten Vorfluters

Critical appraisal of paclitaxel balloon angioplasty for femoral-popliteal arterial disease.

Science.gov (United States)

Herten, Monika; Torsello, Giovanni B; Schönefeld, Eva; Stahlhoff, Stefan

2016-01-01

Peripheral arterial disease, particularly critical limb ischemia, is an area with urgent need for optimized therapies because, to date, vascular interventions often have limited life spans. In spite of initial encouraging technical success after femoropopliteal percutaneous transluminal angioplasty or stenting, postprocedural restenosis remains the major problem. The challenging idea behind the drug-coated balloon (DCB) concept is the biological modification of the injury response after balloon dilatation. Antiproliferative drugs administered via DCBs or drug-eluting stents are able to suppress neointimal hyperplasia, the main cause of restenosis. This article reviews the results of DCB treatments of femoropopliteal and infrapopliteal lesions in comparison to standard angioplasty with uncoated balloons. A systematic literature search was performed in 1) medical journals (ie, MEDLINE), 2) international registers for clinical studies (ie, www.clinicaltrials.gov), and 3) abstracts of scientific sessions. Several controlled randomized trials with follow-up periods of up to 5 years demonstrated the efficacy of paclitaxel -DCB technology. However, calcified lesions seem to affect the efficacy of DCB. Combinations of preconditioning methods with DCBs showed promising results. Although the mechanical abrasion of calcium via atherectomy or laser ablation showed favorable periprocedural results, the long-term impact on restenosis and clinical outcome has to be demonstrated. Major advantages of the DCBs are the rapid delivery of drug at uniform concentrations with a single dose, their efficacy in areas wherein stents have been contraindicated until now (ie, bifurcation, ostial lesions), and in leaving no stent scaffold behind. Reinterventions are easier to perform because DCBs leave no metal behind. Various combinations of DCBs with other treatment modalities may prove to be viable options in future. The follow-up results of clinical studies will evaluate the long-term impact

Preparation of ZnS@In2S3 Core@shell Composite for Enhanced Photocatalytic Degradation of Gaseous o-Dichlorobenzene under Visible Light.

Science.gov (United States)

Liu, Baojun; Hu, Xia; Li, Xinyong; Li, Ying; Chen, Chang; Lam, Kwok-Ho

2017-11-27

In this study, novel ZnS@In 2 S 3 core@shell hollow nanospheres were fabricated by a facile refluxing method for the first time, and the formation mechanism of hollow structure with interior architecture was discussed based on ion-exchange Ostwald ripening. As the photocatalytic material for degradation of gaseous o-Dichlorobenzene (o-DCB), the as-synthesized core@shell hollow nanospheres were found to show significantly enhanced catalytic performance for effective separation of photo-generated charges. Moreover, the mechanisms of enhanced activity were elucidated by band alignment and unique configuration. Such photocatalyst would meet the demands for the control of persistent organic pollutant (POPs) in the atmospheric environment.

Effectiveness of Sunscreen at Preventing Solar UV-Induced Alterations of Human Stratum Corneum

Science.gov (United States)

Martinez, O.; Dauskardt, R.; Biniek, K.; Novoa, F.

2012-12-01

The outermost layer of the epidermis, the stratum corneum, protects the body from harmful environmental conditions by serving as a selective barrier. Solar ultraviolet (UV) radiation is one of the most common conditions the body encounters and is responsible for many negative skin responses, including compromised barrier function. UV exposure has dramatic effects on stratum corneum cell cohesion and mechanical integrity that are related to its effects on the stratum corneum's intercellular lipids. Hypothesis Sunscreen contains chemicals that absorb UV radiation to prevent the radiation from penetrating the skin. Thus, it is expected that the application of sunscreen on human stratum corneum will reduce UV-induced alterations of human stratum corneum. Procedures/Equipment Human tissue was processed in order to isolate the stratum corneum, the top layer of the epidermis. Double cantilever beam (DCB) testing was used to study the effect of UV radiation on human stratum corneum. Two different types of DCB samples were created: control DCB samples with the application of carrier and UV light to the stratum corneum and DCB samples with the application of sunscreen and UV light to the stratum corneum. For the control sample, one side of the stratum corneum was glued to a polycarbonate beam and carrier was applied. Then, the sample was placed 10 cm away from the UV lamp inside of the environmental chamber and were exposed to UV dosages of about 800 J/cm2. Once this step was complete, a second polycarbonate beam was glued to the other side of the stratum corneum. The steps were similar for the DCB sample that had sunscreen applied and that was exposed to UV light. After gluing one side of the stratum corneum to a polycarbonate beam, Octinoxate sunscreen was applied. The next steps were similar to those of the control sample. All DCB samples were then let out to dry for two hours in a dry box in order for the moisture from the lab to be extracted. Each DCB sample was tested

Results of ASTM round robin testing for mode 1 interlaminar fracture toughness of composite materials

Science.gov (United States)

Obrien, T. Kevin; Martin, Roderick H.

1992-01-01

The results are summarized of several interlaboratory 'round robin' test programs for measuring the mode 1 interlaminar fracture toughness of advanced fiber reinforced composite materials. Double Cantilever Beam (DCB) tests were conducted by participants in ASTM committee D30 on High Modulus Fibers and their Composites and by representatives of the European Group on Fracture (EGF) and the Japanese Industrial Standards Group (JIS). DCB tests were performed on three AS4 carbon fiber reinforced composite materials: AS4/3501-6 with a brittle epoxy matrix; AS4/BP907 with a tough epoxy matrix; and AS4/PEEK with a tough thermoplastic matrix. Difficulties encountered in manufacturing panels, as well as conducting the tests are discussed. Critical issues that developed during the course of the testing are highlighted. Results of the round robin testing used to determine the precision of the ASTM DCB test standard are summarized.

Comparison of 3D-Printed Poly-ɛ-Caprolactone Scaffolds Functionalized with Tricalcium Phosphate, Hydroxyapatite, Bio-Oss, or Decellularized Bone Matrix.

Science.gov (United States)

Nyberg, Ethan; Rindone, Alexandra; Dorafshar, Amir; Grayson, Warren L

2017-06-01

Three-dimensional (3D)-printing facilitates rapid, custom manufacturing of bone scaffolds with a wide range of material choices. Recent studies have demonstrated the potential for 3D-printing bioactive (i.e., osteo-inductive) scaffolds for use in bone regeneration applications. In this study, we 3D-printed porous poly-ɛ-caprolactone (PCL) scaffolds using a fused deposition modeling (FDM) process and functionalized them with mineral additives that have been widely used commercially and clinically: tricalcium phosphate (TCP), hydroxyapatite (HA), Bio-Oss (BO), or decellularized bone matrix (DCB). We assessed the "print quality" of the composite scaffolds and found that the print quality of PCL-TCP, PCL-BO, and PCL-DCB measured ∼0.7 and was statistically lower than PCL and PCL-HA scaffolds (∼0.8). We found that the incorporation of mineral particles did not significantly decrease the compressive modulus of the graft, which was on the order of 260 MPa for solid blocks and ranged from 32 to 83 MPa for porous scaffolds. Raman spectroscopy revealed the surfaces of the scaffolds maintained the chemical profile of their dopants following the printing process. We evaluated the osteo-inductive properties of each scaffold composite by culturing adipose-derived stromal/stem cells in vitro and assessing their differentiation into osteoblasts. The calcium content (normalized to DNA) increased significantly in PCL-TCP (p  0.05). Collagen 1 expression was 10-fold greater than PCL in PCL-BO and PCL-DCB (p < 0.05) and osteocalcin expression was 10-fold greater in PCL-BO and PCL-DCB (p < 0.05) as measured by quantitative-real time-polymerase chain reaction. This study suggests that PCL-BO and PCL-DCB hybrid material may be advantageous for bone healing applications over PCL-HA or PCL-TCP blends.

Solar Energy Materials & Solar Cells Solvent additives for tuning the photovoltaic properties of polymer – fullerene solar cells

NARCIS (Netherlands)

Sio, Antonietta De; Madena, Thomas; Huber, Ralph; Deschler, Felix; Como, Enrico Da; Esposito, Salvatore; Hauff, Elizabeth Von

2011-01-01

We use solvent additives as a simple method to tune the photovoltaic performance of poly-3-hexylthiophene (P3HT) and [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) bulk heterojuncton solar cells. 1,2-dichlorobenzene (oDCB) was used as the reference solvent; chlorobenzene (CB) and 1,2,3,4-

Rapid method for Detection of Irradiation Mango Fruits

International Nuclear Information System (INIS)

El Salhy, F.T.

2011-01-01

To detect mango fruits which have been exposed to low doses of gamma rays (0.5-3.0 kGy), three recommended methods by European Committee for Standardization (EN 1784:1996, EN 1785:1996 and EN 1787:2000) were used to study the possibility for identification of irradiated mango fruits (Ewais variety). Fresh mangoes were irradiated to different doses (0.5, 0.75, 1.0 and 3.0 kGy). The first method for determining the volatile hydrocarbons (VHC) was carried out by using florisil column then identified by gas chromatography and mass spectrometry (GC-MS). The major VHCs were C14:1, C15:0 and C17:1 at different doses which increased linearly with increasing doses either at low or high doses. The second one for determining the 2-alkyl cyclobutanone (2-DCB) was carried out using florisil chromatography method activated with 20% for separation and identified by GC-MS. 2-DCB bio marker specific for irradiated food proved its presence at the applied doses from 0.75-3.0 kGy but not at 0.5 kGy. All the mentioned compounds could not detected in non-irradiated samples, which mean that these radiolytic products (VHC and 2-DCB) can be used as a detection markers for irradiated mangoes even at low doses. The third one (EN 1787:2000) was conducted by electron spin resonance (ESR) on dried petioles of mangoes. The results proved that ESR was more sensitive for all applied doses.It could be concluded that using the three methods can be succeeded for detection of irradiated mangoes but the rapid one even at low doses with high accuracy was ESR.

Formation of 2-alkylcyclobutanones in fat-containing irradiated food and evaluation of their toxicity

International Nuclear Information System (INIS)

Todoriki, Setsuko

2003-01-01

2-Alkylcyclobutanones (2-ACB) is unique radiolytic product which is produced by decomposition of triglyceride in fat of food. The effects of 2-ACB on body is not decided. Detection of 2-ACB in food and apply it to determination of irradiated food was studied at the first time by M.H.Stevenson in 1990. The detection methods and the detection results are explained. Nine toxicity tests of 2-ACB were summarized, for examples, genotoxic properties of 2-dodecylcyclobutanone, markers for an irradiation treatment in fat-containing food and induction of oxidative DNA damage by cyclobutanones generated by irradiation of fat-containing food. In WHO (World Health Organization) Statement on 2-Dodecylcyclobutanone and Related Compounds, March 2003, WHO concluded that 2-DCB and 2-ACB did not injure consumer's health on the basis of animal tests for long time and Ams tests. However, WHO expressed that it will promote the studies of toxicity and or carcinogenicity of 2-ACB and resume risk assessment of irradiated food, when new evidences of possibility of risk will be indicated. (S.Y.)

Versatile ruthenium(II) dye towards blue-light emitter and dye-sensitizer for solar cells

Science.gov (United States)

Zanoni, Kassio P. S.; Amaral, Ronaldo C.; Murakami Iha, Neyde Y.; Abreu, Felipe D.; de Carvalho, Idalina M. M.

2018-06-01

A versatile Ru(II) complex bearing an anthracene moiety was synthesized in our search for suitable compounds towards efficient molecular devices. The new engineered dye, cis‑[Ru(dcbH2)(NCS)2(mbpy‑anth)] (dcbH2 = 2,2‧‑bipyridyl‑4,4‧‑dicarboxylic acid, mbpy‑anth = 4‑[N‑(2‑anthryl)carbamoyl]‑4‧‑methyl‑2,2‧‑bipyridine), exhibits a blueish emission in a vibronically structured spectrum ascribed to the fluorescence of a 1LCAnth (ligand centered) excited state in the anthracene and has a potential to be exploited in the fields of smart lighting and displays. This complex was also employed in dye-sensitized solar cells with fairly efficient solar energy conversion with the use of self-assembled TiO2 compact layers beneath the TiO2 mesoporous film to prevent meso‑TiO2/dye back reactions. Further photoelectrochemical investigations through incident photon-to-current efficiency and electrochemical impedance spectra showed that the all-nano-TiO2 compact layer acts as contact layers that increase the electron harvesting in the external circuit, enhancing efficiencies up to 50%.

Dynamic circular buffering: a technique for equilibrium gated blood pool imaging.

Science.gov (United States)

Vaquero, J J; Rahms, H; Green, M V; Del Pozo, F

1996-03-01

We have devised a software technique called "dynamic circular buffering" (DCB) with which we create a gated blood pool image sequence of the heart in real time using the best features of LIST and FRAME mode methods of acquisition/processing. The routine is based on the concept of independent "agents" acting on the timing and position data continuously written into the DCB. This approach allows efficient asynchronous operation on PC-type machines and enhanced capability on systems capable of true multiprocessing and multithreading.

Adhesion of Antireflective Coatings in Multijunction Photovoltaics: Preprint

Energy Technology Data Exchange (ETDEWEB)

Brock, Ryan; Dauskardt, Reinhold H.; Miller, David C.

2016-06-16

The development of a new composite dual cantilever beam (cDCB) thin-film adhesion testing method is reported, which allows the measurement of adhesion on the fragile thin substrates used in multijunction photovoltaics. We address the adhesion of several antireflective coating systems on multijunction cells. By varying interface chemistry and morphology, we demonstrate the ensuing effects on adhesion and help to develop an understanding of how high adhesion can be achieved, as adhesion values ranging from 0.5 J/m2 to 10 J/m2 were measured. Damp Heat (85 degrees C/85% RH) was used to invoke degradation of interfacial adhesion. We show that even with germanium substrates that fracture easily, quantitative measurements of adhesion can still be made at high test yield. The cDCB test is discussed as an important new methodology, which can be broadly applied to any system that makes use of thin, brittle, or otherwise fragile substrates.

Laser-based surface patterning of composite plates for improved secondary adhesive bonding

KAUST Repository

Tao, Ran

2018-03-01

The effects of laser irradiation surface pretreatments on the mode I fracture toughness of adhesively bonded composite joints were evaluated. First, pulsed CO2 laser irradiation was uniformly deployed on carbon fiber reinforced polymer (CFRP) substrates. Next, double cantilever beam (DCB) tests were performed to assess the effects of surface pretreatments on the mode I fracture toughness of the adhesive joints. Then, a thoughtful combination of the proposed surface pretreatments was deployed to fabricate DCB specimens with patterned interfaces. A wide range of techniques, including X-ray photoelectron spectroscopy (XPS), contact profilometry, and optical and scanning electron microscopy (SEM) were used to ascertain the effects of all investigated surface pretreatments. It is shown that patterning promoted damage mechanisms that were not observed in the uniformly treated interfaces, resulting in an effective fracture toughness well above that predicted by a classical rule of mixture.

Laser-based surface patterning of composite plates for improved secondary adhesive bonding

KAUST Repository

Tao, Ran; Alfano, Marco; Lubineau, Gilles

2018-01-01

The effects of laser irradiation surface pretreatments on the mode I fracture toughness of adhesively bonded composite joints were evaluated. First, pulsed CO2 laser irradiation was uniformly deployed on carbon fiber reinforced polymer (CFRP) substrates. Next, double cantilever beam (DCB) tests were performed to assess the effects of surface pretreatments on the mode I fracture toughness of the adhesive joints. Then, a thoughtful combination of the proposed surface pretreatments was deployed to fabricate DCB specimens with patterned interfaces. A wide range of techniques, including X-ray photoelectron spectroscopy (XPS), contact profilometry, and optical and scanning electron microscopy (SEM) were used to ascertain the effects of all investigated surface pretreatments. It is shown that patterning promoted damage mechanisms that were not observed in the uniformly treated interfaces, resulting in an effective fracture toughness well above that predicted by a classical rule of mixture.

Transição epidemiológica da mortalidade por doenças circulatórias no Brasil Transición epidemiológica de la mortalidad por enfermedades circulatorias en Brasil Epidemiologic transition in mortality rate from circulatory diseases in Brazil

Directory of Open Access Journals (Sweden)

Antonio de Padua Mansur

2009-11-01

Full Text Available FUNDAMENTO: As doenças circulatórias (DC são as principais causas de morte no Brasil, com predomínio das doenças cerebrovasculares (DCbV. Nos países desenvolvidos, predominam as doenças isquêmicas do coração (DIC. OBJETIVO: Analisar a relação entre DCbV/DIC em homens e mulheres a partir de 30 anos. MÉTODOS: As estimativas da população e os dados de mortalidade para DC, DIC e DCbV foram obtidos do Ministério da Saúde para o período entre 1980 e 2005. O risco de morte por DIC e DCbV por 100.000 habitantes e a relação entre DCbV/DIC foram analisados nas faixas etárias decenais a partir de 30 anos. O risco de morte foi ajustado pelo método direto, usando como população padrão a população mundial de 1960. RESULTADOS: Observou-se aumento exponencial do risco de morte por DIC e DCbV, com o aumento da faixa etária. DCbV foi a principal causa de morte no Brasil até 1996, quando passou a predominar a DIC. Foi observada redução de 33,25% no risco de morte por DC na população brasileira. Na região metropolitana de São Paulo, houve uma diminuição de 45,44%, entre 1980 e 2005. A relação DCbV/DIC foi maior nas mulheres mais jovens: de 2,53 em 1980 e 2,04 em 2005 para a população brasileira, e de 2,76 em 1980 e 1,96 em 2005 na região metropolitana de São Paulo, com decréscimo nas faixas etárias subsequentes. Nos homens, a relação DCbV/DIC foi próximo de FUNDAMENTO: Las enfermedades circulatorias (EC son las principales causas de muerte en Brasil, con el predominio de las enfermedades cerebrovasculares (ECbV. En los países desarrollados predominan las enfermedades isquémicas del corazón (EIC. OBJETIVO: Analizar la relación entre ECbV/EIC en varones y mujeres a partir de 30 años. MÉTODOS: Se obtuvieron en el Ministério de la Salud las estimaciones de la población y los datos de mortalidad para EC, EIC y ECbV para el periodo entre 1980 y 2005. Se analizaron el riesgo de muerte por EIC y ECbV por 100

DCB - Cancer Immunology, Hematology, and Etiology Research

Science.gov (United States)

Part of NCI’s Division of Cancer Biology’s research portfolio, studies supported include the characterization of basic mechanisms relevant to anti-tumor immune responses and hematologic malignancies.

Peripheral Applications of Drug-Coated Balloons: Past, Present and Future

Energy Technology Data Exchange (ETDEWEB)

Krokidis, Miltiadis, E-mail: mkrokidis@hotmail.com; Spiliopoulos, Stavros, E-mail: stavspiliop@upatras.gr; Katsanos, Konstantinos, E-mail: katsanos@med.upatras.gr; Sabharwal, Tarun, E-mail: tarun_sabharwal@yahoo.co.uk [Guy' s and St. Thomas' Hospitals, NHS Foundation Trust, Department of Radiology (United Kingdom)

2013-04-15

Drug-coated balloon (DCB) technologies represent the latest and hottest development in the field of endovascular treatment of peripheral arterial disease. Initial experience with paclitaxel-coated balloon use in the femoral artery has demonstrated lower mid-term restenosis and superior mid-term clinical outcomes in terms of improved wound healing and reduced repeat angioplasty rates compared with standard balloon angioplasty. Many companies are presently developing and/or improving DCB catheters and therefore ongoing, technical improvements of the already existing platforms, new drugs, and innovative carriers are expected. The ongoing basic research studies and various multicenter randomized, controlled trials that are currently in progress will offer valuable scientific insights regarding the long-term effectiveness and other crucial issues, such as efficacy in various vascular beds, optimal balloon dosage, and post angioplasty antiplatelet therapy. Future applications of these devices also could include in-stent restenosis, anastomotic stenosis of surgical bypass, and benign stenoses of the central venous system. The authors envision that DCB angioplasty will evolve to a major paradigm shift in the endovascular treatment of occlusive vascular diseases.

Peripheral Applications of Drug-Coated Balloons: Past, Present and Future

International Nuclear Information System (INIS)

Krokidis, Miltiadis; Spiliopoulos, Stavros; Katsanos, Konstantinos; Sabharwal, Tarun

2013-01-01

Drug-coated balloon (DCB) technologies represent the latest and hottest development in the field of endovascular treatment of peripheral arterial disease. Initial experience with paclitaxel-coated balloon use in the femoral artery has demonstrated lower mid-term restenosis and superior mid-term clinical outcomes in terms of improved wound healing and reduced repeat angioplasty rates compared with standard balloon angioplasty. Many companies are presently developing and/or improving DCB catheters and therefore ongoing, technical improvements of the already existing platforms, new drugs, and innovative carriers are expected. The ongoing basic research studies and various multicenter randomized, controlled trials that are currently in progress will offer valuable scientific insights regarding the long-term effectiveness and other crucial issues, such as efficacy in various vascular beds, optimal balloon dosage, and post angioplasty antiplatelet therapy. Future applications of these devices also could include in-stent restenosis, anastomotic stenosis of surgical bypass, and benign stenoses of the central venous system. The authors envision that DCB angioplasty will evolve to a major paradigm shift in the endovascular treatment of occlusive vascular diseases.

Chlorinated aliphatic and aromatic VOC decomposition in air mixture by using electron beam irradiation

International Nuclear Information System (INIS)

Chmielewski, A.G.; Sun Yongxia; Bulka, S.; Zimek, Z.

2004-01-01

Chlorinated aliphatic and aromatic hydrocarbons, which are emitted from coal power station and waste incinerators, are very harmful to the environment and human health. Recent studies show that chlorinated aliphatic and aromatic hydrocarbons are suspected to be the precursors of dioxin's formation. Dioxin's emission into atmosphere will cause severe environmental problems by ecology contamination. l,4-dichlorobenzene(l,4-DCB) and cis-dichloroethylene(cis-DCE) were chosen as representative chlorinated aromatic and aliphatic compounds, respectively. Their decomposition was investigated by electron beam irradiation. The experiments were carried out 'in batch' system. It is found that over 97% cis-DCE is decomposed having an initial concentration of 661 ppm. G-values of cis-DCE decomposition vary from 10 to 28 (molecules/100 eV) for initial concentration of 270-1530 ppm cis-DCE. The decomposition is mainly caused by secondary electron attachment and Cl addition reactions. Comparing with cis-DCE, 1,4-DCB decomposition needs higher absorbed dose. G-value of 1,4-DCB is below 4 molecules/100 eV

Influence of extractable soil manganese on oxidation capacity of different soils in Korea

Science.gov (United States)

Chon, Chul-Min; Kim, Jae Gon; Lee, Gyoo Ho; Kim, Tack Hyun

2008-08-01

We examined the relationship between soil oxidation capacity and extractable soil manganese, iron oxides, and other soil properties. The Korean soils examined in this study exhibited low to medium Cr oxidation capacities, oxidizing 0.00-0.47 mmol/kg, except for TG-4 soils, which had the highest capacity for oxidizing added Cr(III) [>1.01 mmol/kg of oxidized Cr(VI)]. TG and US soils, with high Mn contents, had relatively high oxidation capacities. The Mn amounts extracted by dithionite-citrate-bicarbonate (DCB) (Mnd), NH2OH·HCl (Mnh), and hydroquinone (Mnr) were generally very similar, except for the YS1 soils, and were well correlated. Only small proportions of either total Mn or DCB-extractable Mn were extracted by NH2OH·HCl and hydroquinone in the YS1 soils, suggesting inclusion of NH2OH·HCl and hydroquinone-resistant Mn oxides, because these extractants are weaker reductants than DCB. No Cr oxidation test results were closely related to total Mn concentrations, but Mnd, Mnh, and Mnr showed a relatively high correlation with the Cr tests ( r = 0.655-0.851; P Mnh were better correlated with the Cr oxidation tests than was the Mnr concentration, suggesting that the oxidation capacity of our soil samples can be better explained by Mnd and Mnh than by Mnr. The first component in principal components analysis indicated that extractable soil Mn was a main factor controlling net Cr oxidation in the soils. Total soil Mn, Fe oxides, and the clay fraction are crucial for predicting the mobility of pollutants and heavy metals in soils. The second principal component indicated that the presence of Fe oxides in soils had a significant relationship with the clay fraction and total Mn oxide, and was also related to heavy-metal concentrations (Zn, Cd, and Cu, but not Pb).

A Novel Procedure for Prediction of Mixed Mode I/II in Fracture Toughness of Laminate Composites

Directory of Open Access Journals (Sweden)

M. Mahmood Shokrieh

2014-06-01

Full Text Available Delamination is one of the important modes of failure in laminated composite materials. In this respect, the mixed mode I/II fracture is the most major mode of delamination incidence in laminated composite. In the present research, a relation between the fracture toughness of double cantilever beam (DCB and asymmetric double cantilever beam (ADCB specimens is presented. The DCB and ADCB samples are used for measuring the mode I and mixed mode I/II fracture toughness (G of laminated composite materials, respectively. By considering the diversity of the stacking sequence of lay-ups, the test performance on all different types of lay-ups in order to measure the fracture toughness of laminated composites is a tedious, costly and time consuming task. The purpose of deriving this relation is to estimate the value of the strain energy release rate of laminated composite ADCB specimens by testing a unidirectional DCB. To develop this relationship, the geometry of DCB and ADCB specimens are considered to obtain fracture toughness of multi-directional laminate composites of ADCB samples with arbitrary ply sequence which may be used for design purposes. The procedure presented here reduces the calculation costs of the finite element modeling and its corresponding test significantly. The results obtained by this method are compared with those of experimental and numerical methods. It is shown that the fracture toughness of multi-directional lay-ups can be predicted by measuring the unidirectional ply with an error less than 10% demonstrating the accuracy of the procedure developed in the present research.

Real-time observation of intersystem crossing induced by charge recombination during bimolecular electron transfer reactions

KAUST Repository

Alsam, Amani Abdu

2016-09-21

Real-time probing of intersystem crossing (ISC) and triplet-state formation after photoinduced electron transfer (ET) is a particularly challenging task that can be achieved by time-resolved spectroscopy with broadband capability. Here, we examine the mechanism of charge separation (CS), charge recombination (CR) and ISC of bimolecular photoinduced electron transfer (PET) between poly[(9,9-di(3,3′-N,N’-trimethyl-ammonium) propyl fluorenyl-2,7-diyl)-alt-co-(9,9-dioctyl-fluorenyl-2,7-diyl)] diiodide salt (PFN) and dicyanobenzene (DCB) using time-resolved spectroscopy. PET from PFN to DCB is confirmed by monitoring the transient absorption (TA) and infrared spectroscopic signatures for the radical ion pair (DCB─•-PFN+•). In addition, our time-resolved results clearly demonstrate that CS takes place within picoseconds followed by CR within nanoseconds. The ns-TA data exhibit the clear spectroscopic signature of PFN triplet-triplet absorption, induced by the CR of the radical ion pairs (DCB─•-PFN+•). As a result, the triplet state of PFN (3PFN*) forms and subsequently, the ground singlet state is replenished within microseconds. © 2016

Tailoring Sandwich Face/Core Interfaces for Improved Damage Tolerance

DEFF Research Database (Denmark)

Lundsgaard-Larsen, Christian; Berggreen, Christian; Carlsson, Leif A.

2010-01-01

Various modifications of the face/core interface in foam core sandwich specimens are examined in a series of two papers. This paper constitutes part I and describes the finite element analysis of a sandwich test specimen, i.e. a DCB specimen loaded by uneven bending moments (DCB-UBM). Using...... this test almost any mode-mixity between pure mode I and mode II can be obtained. A cohesive zone model of the mixed mode fracture process involving large-scale bridging is developed. Results from the analysis are used in Part II, which describes methods and results of a series of experiments....

Bulk heterojunction organic photovoltaic cell fabricated by the electrospray deposition method using mixed organic solvent

Energy Technology Data Exchange (ETDEWEB)

Fukuda, Takeshi; Takagi, Kenji; Asano, Takashi [Department of Functional Materials Science, Graduate School of Science and Engineering, Saitama University, 255 Shimo-Okubo, Sakura-ku, Saitama 338-8570 (Japan); RIKEN, 2-1 Hirosawa, Wakou-shi, Saitama 351-0198 (Japan); Honda, Zentaro; Kamata, Norihiko; Ueno, Keiji; Shirai, Hajime [Department of Functional Materials Science, Graduate School of Science and Engineering, Saitama University, 255 Shimo-Okubo, Sakura-ku, Saitama 338-8570 (Japan); Ju, Jungmyoung; Yamagata, Yutaka; Tajima, Yusuke [RIKEN, 2-1 Hirosawa, Wakou-shi, Saitama 351-0198 (Japan)

2011-07-15

A high-efficiency bulk heterojunction organic photovoltaic cell (OPV) was achieved by the electrospray deposition method. The surface roughness of the P3HT:PCBM thin film can be reduced using the mixed solvent consisting of o-dichlorobenzene (o-DCB) and acetone. The effect of acetone concentration is related to its dielectric constant. Under an optimized concentration of acetone in o-DCB (20 vol%), the P3HT/PCBM active layer with a smooth surface can be formed, and the power conversion efficiency of the OPV was 1.9%. (copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Magnetic headspace adsorptive extraction of chlorobenzenes prior to thermal desorption gas chromatography-mass spectrometry

International Nuclear Information System (INIS)

Vidal, Lorena; Ahmadi, Mazaher; Fernández, Elena; Madrakian, Tayyebeh; Canals, Antonio

2017-01-01

This study presents a new, user-friendly, cost-effective and portable headspace solid-phase extraction technique based on graphene oxide decorated with iron oxide magnetic nanoparticles as sorbent, located on one end of a small neodymium magnet. Hence, the new headspace solid-phase extraction technique has been called Magnetic Headspace Adsorptive Extraction (Mag-HSAE). In order to assess Mag-HSAE technique applicability to model analytes, some chlorobenzenes were extracted from water samples prior to gas chromatography-mass spectrometry determination. A multivariate approach was employed to optimize the experimental parameters affecting Mag-HSAE. The method was evaluated under optimized extraction conditions (i.e., sample volume, 20 mL; extraction time, 30 min; sorbent amount, 10 mg; stirring speed, 1500 rpm, and ionic strength, non-significant), obtaining a linear response from 0.5 to 100 ng L −1 for 1,3-DCB, 1,4-DCB, 1,2-DCB, 1,3,5-TCB, 1,2,4-TCB and 1,2,3-TCB; from 0.5 to 75 ng L −1 for 1,2,4,5-TeCB, and PeCB; and from 1 to 75 ng L −1 for 1,2,3,4-TeCB. The repeatability of the proposed method was evaluated at 10 ng L −1 and 50 ng L −1 spiking levels, and coefficients of variation ranged between 1.5 and 9.5% (n = 5). Limits of detection values were found between 93 and 301 pg L −1 . Finally, tap, mineral and effluent water were selected as real water samples to assess method applicability. Relative recoveries varied between 86 and 110% showing negligible matrix effects. - Highlights: • A new extraction technique named Magnetic Headspace Adsorptive Extraction is presented. • Graphene oxide/iron oxide composite deposited on a neodymiun magnet as sorbent. • Sorbent of low cost, rapid and simple synthesis, easy manipulation and portability options. • Fast and efficient extraction and sensitive determination of chlorobenzenes in water samples.

A rapid supercritical fluid extraction method for the qualitative detection of 2-alkylcyclobutanones in gamma-irradiated fresh and sea water fish

International Nuclear Information System (INIS)

Tewfik, I.H.; Ismail, H.M.; Sumar, S.

1999-01-01

2-Alkylcyclobutanones are routinely used as chemical markers for irradiated foods containing lipids. However, current extraction procedures (soxhlet-Florisil chromatography) for the isolation of these markers involve a long and tedious clean-up regime prior to GC-MS identification. A simple and rapid method for the isolation of these markers using carbon dioxide as a super critical fluid is described for low lipid content fish samples (fresh and sea water) irradiated up to 8kGy. The presence of 2-dodecylcyclobutanone (2-DCB), a radiolytic marker, was confirmed in all irradiated fish samples at all doses. This was a clear indication that the fish samples had been irradiated and that both methods of isolation (florisil and supercritical fluid extraction) were capable of qualitatively extracting this marker. Supercritical fluid extraction is proposed as an alternative extraction procedure to the florisil chromatography method currently in use and has the added advantage of a considerably shorter extraction time

Moessbauer studies on some Argentinian soil: mollisols from Bahia Blanca

International Nuclear Information System (INIS)

Saragovi, C.; Venegas, R.

1994-01-01

Clay fractions of a Mollisol sample as is, treated with ammonium oxalate (AO), with dithionite-citrate-bicarbonate (DCB) and with dithionite-ethilene-diamine- tetraacetic acid (D-EDTA) methods, were studied. Illite-montmorillonites together with hematites, goethites and maghemites, all of the Al-substituted and with a wide range of sizes, were identified. It is found that the AO attack extracts little iron, whereas the other two attacks extract the magnetic signal. Furthermore, the DCB attack facilitates the reduction of the Fe 3+ ions, while the D-EDTA method does not. Instead, this attack extracts more clay mineral Fe ions. A comparison with large grain soil samples is made. (orig.)

Mössbauer studies on some Argentinian soil: Mollisols from Bahia Blanca

Science.gov (United States)

Saragovi, C.; Labenski, F.; Duhalde, S. M.; Acebal, S.; Venegas, R.

1994-12-01

Clay fractions of a Mollisol sample as is, treated with ammonium oxalate (AO), with dithionite-citrate-bicarbonate (DCB) and with dithionite-ethilene-diamine-tetraacetic acid (D-EDTA) methods, were studied. Illite-montmorillonites together with hematites, goethites and maghemites, all of the AI-substituted and with a wide range of sizes, were identified. It is found that the AO attack extracts little iron, whereas the other two attacks extract the magnetic signal. Furthermore, the DCB attack facilitates the reduction of the Fe3+ ions, while the D-EDTA method does not. Instead, this attack extracts more clay mineral Fe ions. A comparison with large grain soil samples is made.

Isolation and Partial Characterization of Bacteria in an Anaerobic Consortium That Mineralizes 3-Chlorobenzoic Acid †

OpenAIRE

Shelton, Daniel R.; Tiedje, James M.

1984-01-01

A methanogenic consortium able to use 3-chlorobenzoic acid as its sole energy and carbon source was enriched from anaerobic sewage sludge. Seven bacteria were isolated from the consortium in mono- or coculture. They included: one dechlorinating bacterium (strain DCB-1), one benzoate-oxidizing bacterium (strain BZ-2), two butyrate-oxidizing bacteria (strains SF-1 and NSF-2), two H2-consuming methanogens (Methanospirillum hungatei PM-1 and Methanobacterium sp. strain PM-2), and a sulfate-reduci...

Airland Battle Doctrine

Science.gov (United States)

1988-09-01

Professional Paper 463 / September 1988 OTIC - EL cOPY V 0- 00 00 N Airland Battle Doctrine DTIC S ELECTE DEC 2 81988D Douglas W. Skinner Dcb A...missiles to ground targets. Initial deployment will be on the Army’s OV-i Bronco and the Air Force’s TR-l and C-18. This is another outgrowth of the

InterProScan Result: FS783911 [KAIKOcDNA[Archive

Lifescience Database Archive (English)

Full Text Available FS783911 FS783911_6_ORF1 F4FB77A4630C2DCB PRINTS PR00385 P450 8.8e-13 T IPR001128 Cytochrome P450 Molecular... Function: monooxygenase activity (GO:0004497)|Molecular Function: iron ion binding (GO:0005506)|Molecular... Function: electron carrier activity (GO:0009055)|Molecular Function: heme binding (GO:0020037) ...

Rhodium based clusters for oxygen reduction and hydrogen oxidation in 0.5 M H2SO4, tolerant to methanol and carbon monoxide, respectively

Energy Technology Data Exchange (ETDEWEB)

Uribe-Godinez, J.; Jimenez-Sandoval, O.; Borja-Arco, E.; Altamirano-Gutierrez, A. [Centro de Investigacion y de Estudios Avanzados del Instituto Politecnico Nacional, Queritaro (Mexico); Castellanos, R.H. [Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada-Queretaro, Queretaro (Mexico)

2008-07-01

Rhodium (Rh6(CO)16) and novel Rh-based clusters were prepared using thermolysis techniques under different conditions in N2 and H2 reaction media, as well as in n-nonane, o-xylene, 1,2-dichlorobenzene and dimethylsulfoxide. The clusters were used as novel electrocatalysts for oxygen reduction reaction (ORR) in the absence and presence of 1.0 and 2.0 M methanol solutions. The catalysts were also used for hydrogen oxidation reaction (HOR) with pure hydrogen (H2) and in the presence of carbon monoxide (CO). Rotating disk electrode measurements were used to analyze the materials. The study showed that the electrocatalyst support ratio plays a significant role in the electrochemical behaviour of the materials. Rh6(CO)16 and Rh2(1,2-DCB) presented the best electrocatalytic behaviour for ORR and HOR in the absence and presence of methanol and CO. The study demonstrated that the rhodium-based materials are capable of performing ORR and HOR while being tolerant of both methanol and CO. 3 refs., 3 figs.

Inkjet Assisted Creation of Self-Healing Layers Between Composite Plies

Science.gov (United States)

2013-07-29

technology into a prepreg manufacturing process. The approach consisted of depositing novel thermoplastic low-viscosity microdroplets with chemically and...mechanically comparable properties to epoxy matrix in aerospace grade composites onto fiber-reinforced epoxy prepregs before curing using an ink-jet... prepreg Cycom977-2. Double cantilever beam (DCB) and short beam shear (SBS) tests were used to evaluate the self-healing efficiency. It was shown

Timing group delay and differential code bias corrections for BeiDou positioning

Science.gov (United States)

Guo, Fei; Zhang, Xiaohong; Wang, Jinling

2015-05-01

This article first clearly figures out the relationship between parameters of timing group delay (TGD) and differential code bias (DCB) for BDS, and demonstrates the equivalence of TGD and DCB correction models combining theory with practice. The TGD/DCB correction models have been extended to various occasions for BDS positioning, and such models have been evaluated by real triple-frequency datasets. To test the effectiveness of broadcast TGDs in the navigation message and DCBs provided by the Multi-GNSS Experiment (MGEX), both standard point positioning (SPP) and precise point positioning (PPP) tests are carried out for BDS signals with different schemes. Furthermore, the influence of differential code biases on BDS positioning estimates such as coordinates, receiver clock biases, tropospheric delays and carrier phase ambiguities is investigated comprehensively. Comparative analysis show that the unmodeled differential code biases degrade the performance of BDS SPP by a factor of two or more, whereas the estimates of PPP are subject to varying degrees of influences. For SPP, the accuracy of dual-frequency combinations is slightly worse than that of single-frequency, and they are much more sensitive to the differential code biases, particularly for the B2B3 combination. For PPP, the uncorrected differential code biases are mostly absorbed into the receiver clock bias and carrier phase ambiguities and thus resulting in a much longer convergence time. Even though the influence of the differential code biases could be mitigated over time and comparable positioning accuracy could be achieved after convergence, it is suggested to properly handle with the differential code biases since it is vital for PPP convergence and integer ambiguity resolution.

Laser synthesized super-hydrophobic conducting carbon with broccoli-type morphology as a counter-electrode for dye sensitized solar cells

Science.gov (United States)

Gokhale, Rohan; Agarkar, Shruti; Debgupta, Joyashish; Shinde, Deodatta; Lefez, Benoit; Banerjee, Abhik; Jog, Jyoti; More, Mahendra; Hannoyer, Beatrice; Ogale, Satishchandra

2012-10-01

A laser photochemical process is introduced to realize superhydrophobic conducting carbon coatings with broccoli-type hierarchical morphology for use as a metal-free counter electrode in a dye sensitized solar cell. The process involves pulsed excimer laser irradiation of a thin layer of liquid haloaromatic organic solvent o-dichlorobenzene (DCB). The coating reflects a carbon nanoparticle-self assembled and process-controlled morphology that yields solar to electric power conversion efficiency of 5.1% as opposed to 6.2% obtained with the conventional Pt-based electrode.A laser photochemical process is introduced to realize superhydrophobic conducting carbon coatings with broccoli-type hierarchical morphology for use as a metal-free counter electrode in a dye sensitized solar cell. The process involves pulsed excimer laser irradiation of a thin layer of liquid haloaromatic organic solvent o-dichlorobenzene (DCB). The coating reflects a carbon nanoparticle-self assembled and process-controlled morphology that yields solar to electric power conversion efficiency of 5.1% as opposed to 6.2% obtained with the conventional Pt-based electrode. Electronic supplementary information (ESI) available: Materials and equipment details, solar cell fabrication protocol, electrolyte spreading time measurement details, XPS spectra, electronic study, film adhesion test detailed analysis and field emission results. See DOI: 10.1039/c2nr32082g

A method of estimating GPS instrumental biases with a convolution algorithm

Science.gov (United States)

Li, Qi; Ma, Guanyi; Lu, Weijun; Wan, Qingtao; Fan, Jiangtao; Wang, Xiaolan; Li, Jinghua; Li, Changhua

2018-03-01

This paper presents a method of deriving the instrumental differential code biases (DCBs) of GPS satellites and dual frequency receivers. Considering that the total electron content (TEC) varies smoothly over a small area, one ionospheric pierce point (IPP) and four more nearby IPPs were selected to build an equation with a convolution algorithm. In addition, unknown DCB parameters were arranged into a set of equations with GPS observations in a day unit by assuming that DCBs do not vary within a day. Then, the DCBs of satellites and receivers were determined by solving the equation set with the least-squares fitting technique. The performance of this method is examined by applying it to 361 days in 2014 using the observation data from 1311 GPS Earth Observation Network (GEONET) receivers. The result was crosswise-compared with the DCB estimated by the mesh method and the IONEX products from the Center for Orbit Determination in Europe (CODE). The DCB values derived by this method agree with those of the mesh method and the CODE products, with biases of 0.091 ns and 0.321 ns, respectively. The convolution method's accuracy and stability were quite good and showed improvements over the mesh method.

Magnetic headspace adsorptive extraction of chlorobenzenes prior to thermal desorption gas chromatography-mass spectrometry

Energy Technology Data Exchange (ETDEWEB)

Vidal, Lorena, E-mail: lorena.vidal@ua.es [Department of Analytical Chemistry, Nutrition and Food Sciences and University Institute of Materials, University of Alicante, P.O. Box 99, E-03080, Alicante (Spain); Ahmadi, Mazaher [Faculty of Chemistry, Bu-Ali Sina University, Hamedan (Iran, Islamic Republic of); Fernández, Elena [Department of Analytical Chemistry, Nutrition and Food Sciences and University Institute of Materials, University of Alicante, P.O. Box 99, E-03080, Alicante (Spain); Madrakian, Tayyebeh [Faculty of Chemistry, Bu-Ali Sina University, Hamedan (Iran, Islamic Republic of); Canals, Antonio, E-mail: a.canals@ua.es [Department of Analytical Chemistry, Nutrition and Food Sciences and University Institute of Materials, University of Alicante, P.O. Box 99, E-03080, Alicante (Spain)

2017-06-08

This study presents a new, user-friendly, cost-effective and portable headspace solid-phase extraction technique based on graphene oxide decorated with iron oxide magnetic nanoparticles as sorbent, located on one end of a small neodymium magnet. Hence, the new headspace solid-phase extraction technique has been called Magnetic Headspace Adsorptive Extraction (Mag-HSAE). In order to assess Mag-HSAE technique applicability to model analytes, some chlorobenzenes were extracted from water samples prior to gas chromatography-mass spectrometry determination. A multivariate approach was employed to optimize the experimental parameters affecting Mag-HSAE. The method was evaluated under optimized extraction conditions (i.e., sample volume, 20 mL; extraction time, 30 min; sorbent amount, 10 mg; stirring speed, 1500 rpm, and ionic strength, non-significant), obtaining a linear response from 0.5 to 100 ng L{sup −1} for 1,3-DCB, 1,4-DCB, 1,2-DCB, 1,3,5-TCB, 1,2,4-TCB and 1,2,3-TCB; from 0.5 to 75 ng L{sup −1} for 1,2,4,5-TeCB, and PeCB; and from 1 to 75 ng L{sup −1} for 1,2,3,4-TeCB. The repeatability of the proposed method was evaluated at 10 ng L{sup −1} and 50 ng L{sup −1} spiking levels, and coefficients of variation ranged between 1.5 and 9.5% (n = 5). Limits of detection values were found between 93 and 301 pg L{sup −1}. Finally, tap, mineral and effluent water were selected as real water samples to assess method applicability. Relative recoveries varied between 86 and 110% showing negligible matrix effects. - Highlights: • A new extraction technique named Magnetic Headspace Adsorptive Extraction is presented. • Graphene oxide/iron oxide composite deposited on a neodymiun magnet as sorbent. • Sorbent of low cost, rapid and simple synthesis, easy manipulation and portability options. • Fast and efficient extraction and sensitive determination of chlorobenzenes in water samples.

Development of Embedded Vascular Networks in FRP for Active/Passive Thermal Management

Science.gov (United States)

2015-04-01

Fig 2.1. Hand layup of PLA coated NiCr wire into fibre direction cut-outs (SE70 Glass/epoxy prepreg ) Fig 2.2...cure   unidirectional   prepreg   tape   (SE70,   carbon  fibre/epoxy,  Gurit  UK),  Fig.  2.4  and  Fig.  2.5.  To...Tg  of  the  cured   laminate  would  be  126°C.   Mode  I  DCB  testing  was  performed  according  to  the

Exploring the Genome and Proteome of Desulfitobacterium hafniense DCB2 for its Protein Complexes Involved in Metal Reduction and Dechlorination

Energy Technology Data Exchange (ETDEWEB)

Sang-Hoon, Kim; Hardzman, Christina; Davis, John k.; Hutcheson, Rachel; Broderick, Joan B.; Marsh, Terence L.; Tiedje, James M.

2012-09-27

Desulfitobacteria are of interest to DOE mission because of their ability to reduce many electron acceptors including Fe(III), U(VI), Cr(VI), As(V), Mn(IV), Se(VI), NO₃- and well as CO₂, sulfite, fumarate and humates, their ability to colonize more stressful environments because they form spores, fix nitrogen and they have the more protective Gram positive cell walls. Furthermore at least some of them reductively dechlorinate aromatic and aliphatic pollutants. Importantly, most of the metals and the organochlorine reductions are coupled to ATP production and support growth providing for the organism's natural selection at DOE's contaminant sites. This work was undertaken to gain insight into the genetic and metabolic pathways involved in dissimilatory metal reduction and reductive dechlorination, (ii) to discern the commonalities among these electron-accepting processes, (iii) to identify multi-protein complexes catalyzing these functions and (iv) to elucidate the coordination in expression of these pathways and processes.

Rush-hour aromatic and chlorinated hydrocarbons in selected subway stations of Shanghai, China.

Science.gov (United States)

Zhang, Yanli; Li, Chunlei; Wang, Xinming; Guo, Hai; Feng, Yanli; Chen, Jianmin

2012-01-01

Air samples were collected simultaneously at platform, mezzanine and outdoor in five typical stations of subway system in Shanghai, China using stainless steel canisters and analyzed by gas chromatography-mass selective detector (GC-MSD) after cryogenic preconcentration. Benzene, toluene, ethylbenzene and xylenes (BTEX) at the platforms and mezzanines inside the stations averaged (10.3 +/- 2.1), (38.7 +/- 9.0), (19.4 +/- 10.1) and (30.0 +/- 11.1) microg/m3, respectively; while trichloroethylene (TrCE), tetrachloroethylene (TeCE) and para-dichlorobenzene (pDCB), vinyl chloride and carbon tetrachloride were the most abundant chlorinated hydrocarbons inside the stations with average levels of (3.6 +/- 1.3), (1.3 +/- 0.5), (4.1 +/- 1.1), (2.2 +/- 1.1) and (1.2 +/- 0.3) microg/m3, respectively. Mean levels of major aromatic and chlorinated hydrocarbons were higher indoor (platforms and mezzanines) than outdoor with average indoor/outdoor (I/O) ratios of 1.1-9.5, whereas no significant indoor/outdoor differences were found except for benzene and TrCE. The highly significant mutual correlations (p subway stations from indoor/outdoor air exchange and traffic emission should be their dominant source. TrCE and pDCB were mainly from indoor emission and TeCE might have both indoor emission sources and contribution from outdoor air, especially in the mezzanines.

Removal of chlorinated organic compounds from gas phase using electron beam technology

Energy Technology Data Exchange (ETDEWEB)

Sun, Y.; Bulka, S.; Zimek, A. [Institute of Nuclear Chemistry and Technology, Warsaw (Poland); Chmielewski, A. G. [Institute of Nuclear Chemistry and Technology, Warsaw (Poland); Faculty of Chemical and Process Engineering, Warsaw University of Technology, Warsaw (Poland)

2011-07-01

Selected chlorinated organic compounds (Cl-HC), which are emitted from coal fired power plants, waste incinerators, chemical industry etc., are very harmful to the environment and human’s health. Some of them are listed as carcinogenic compounds by USA EPA. Recent studies show that some chlorinated organic compounds are suspected to be precursors for dioxins formation. Chlorinated organic compounds decomposition in air in an electron beam (EB) generated plasma reactor technology was studied. We selected cis-dichloroethylene (cis-DCE), 1,4-dichlorobenznene(1,4-DCB), 1-chloronaphthalene as studied objects. It is found that chlorinated organic compounds can be decomposed in an electron beam generated plasma reactor. The order of decomposition efficiency of these compounds are: cis-DCE > 1,4-DCB> 1-chloronaphthalene. (author)

Edge Stenosis After Covered Stenting for Long Superficial Femoral Artery Occlusive Disease: Risk Factor Analysis and Prevention With Drug-Coated Balloon Angioplasty.

Science.gov (United States)

Lin, Ting-Chao; Huang, Chun-Yang; Chen, Po-Lin; Lee, Chiu-Yang; Shih, Chun-Che; Chen, I-Ming

2018-06-01

To report a retrospective analysis of risk factors for edge restenosis after Viabahn stent-graft treatment of superficial femoral artery (SFA) occlusive disease and determine any protective effect of drug-coated balloons (DCBs) used at the time of stent-graft implantation. Between October 2011 and July 2016, 110 patients (mean age 73.3±7.6 years; 78 men) were treated with the Viabahn stent-graft for long SFA occlusions. Thirty-eight (34.5%) patients had DCB reinforcement at the distal edge of the stent-graft. For analysis, the population was divided into groups of no edge stenosis patients (n=88; mean lesion length 22.4±4.2 cm) and edge stenosis patients (n=22; mean lesion length 23.5±5.7 cm). The clinical outcomes, ankle-brachial indices, computed tomography angiography findings, and patency were compared at a minimum of 12 months. Logistic regression analysis was employed to determine risk factors for edge stenosis; the results are presented as the odds ratio (OR) and 95% confidence interval. No differences in clinical or procedural characteristics were identified except the higher incidence of diabetes (p=0.008) and greater need for retrograde access (p=0.033) in the edge stenosis group. DCB reinforcement reduced the incidence of edge stenosis (p=0.021) and target lesion revascularization (TLR; p=0.010) and resulted in a significantly higher 1-year primary patency rate (92.1% vs 76.4%, p=0.042). However, multivariate analysis revealed only poor distal runoff (OR 0.31, 95% CI 0.11 to 0.83, p=0.020) as a predictor of edge stenosis. The risk of edge stenosis after Viabahn implantation was higher in patients with poor distal runoff. DCB reinforcement over the distal edge reduced edge stenosis, decreased 1-year TLR, and improved 1-year primary patency.

Characterization of Mode I and Mode II delamination growth and thresholds in AS4/PEEK composites

Science.gov (United States)

Martin, Roderick H.; Murri, Gretchen Bostaph

1990-01-01

Composite materials often fail by delamination. The onset and growth of delamination in AS4/PEEK, a tough thermoplastic matrix composite, was characterized for mode 1 and mode 2 loadings, using the Double Cantilever Beam (DCB) and the End Notched Flexure (ENF) test specimens. Delamination growth per fatigue cycle, da/dN, was related to strain energy release rate, G, by means of a power law. However, the exponents of these power laws were too large for them to be adequately used as a life prediction tool. A small error in the estimated applied loads could lead to large errors in the delamination growth rates. Hence strain energy release rate thresholds, G sub th, below which no delamination would occur were also measured. Mode 1 and 2 threshold G values for no delamination growth were found by monitoring the number of cycles to delamination onset in the DCB and ENF specimens. The maximum applied G for which no delamination growth had occurred until at least 1,000,000 cycles was considered the threshold strain energy release rate. Comments are given on how testing effects, facial interference or delamination front damage, may invalidate the experimental determination of the constants in the expression.

Assessment of global and gene-specific DNA methylation in rat liver and kidney in response to non-genotoxic carcinogen exposure

Energy Technology Data Exchange (ETDEWEB)

Ozden, Sibel, E-mail: stopuz@istanbul.edu.tr [Department of Pharmaceutical Toxicology, Faculty of Pharmacy, Istanbul University, Istanbul (Turkey); Turgut Kara, Neslihan [Department of Molecular Biology and Genetics, Faculty of Science, Istanbul University, Istanbul (Turkey); Sezerman, Osman Ugur [Department of Biostatistics and Medical Informatics, Acibadem University, Istanbul (Turkey); Durasi, İlknur Melis [Biological Sciences and Bioengineering, Faculty of Engineering and Natural Sciences, Sabancı University, Istanbul (Turkey); Chen, Tao [Department of Toxicology, School of Public Health, Soochow University, Suzhou (China); Demirel, Goksun; Alpertunga, Buket [Department of Pharmaceutical Toxicology, Faculty of Pharmacy, Istanbul University, Istanbul (Turkey); Chipman, J. Kevin [School of Biosciences, The University of Birmingham, Birmingham (United Kingdom); Mally, Angela [Department of Toxicology, University of Würzburg, Würzburg (Germany)

2015-12-01

Altered expression of tumor suppressor genes and oncogenes, which is regulated in part at the level of DNA methylation, is an important event involved in non-genotoxic carcinogenesis. This may serve as a marker for early detection of non-genotoxic carcinogens. Therefore, we evaluated the effects of non-genotoxic hepatocarcinogens, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), hexachlorobenzene (HCB), methapyrilene (MPY) and male rat kidney carcinogens, d-limonene, p-dichlorobenzene (DCB), chloroform and ochratoxin A (OTA) on global and CpG island promoter methylation in their respective target tissues in rats. No significant dose-related effects on global DNA hypomethylation were observed in tissues of rats compared to vehicle controls using LC–MS/MS in response to short-term non-genotoxic carcinogen exposure. Initial experiments investigating gene-specific methylation using methylation-specific PCR and bisulfite sequencing, revealed partial methylation of p16 in the liver of rats treated with HCB and TCDD. However, no treatment related effects on the methylation status of Cx32, e-cadherin, VHL, c-myc, Igfbp2, and p15 were observed. We therefore applied genome-wide DNA methylation analysis using methylated DNA immunoprecipitation combined with microarrays to identify alterations in gene-specific methylation. Under the conditions of our study, some genes were differentially methylated in response to MPY and TCDD, whereas d-limonene, DCB and chloroform did not induce any methylation changes. 90-day OTA treatment revealed enrichment of several categories of genes important in protein kinase activity and mTOR cell signaling process which are related to OTA nephrocarcinogenicity. - Highlights: • Studied non-genotoxic carcinogens caused no change on global DNA hypomethylation. • d-Limonene, DCB and chloroform did not show any genome-wide methylation changes. • Some genes were differentially methylated in response to MPY, TCDD and OTA. • Protein kinase activity

Assessment of global and gene-specific DNA methylation in rat liver and kidney in response to non-genotoxic carcinogen exposure

International Nuclear Information System (INIS)

Ozden, Sibel; Turgut Kara, Neslihan; Sezerman, Osman Ugur; Durasi, İlknur Melis; Chen, Tao; Demirel, Goksun; Alpertunga, Buket; Chipman, J. Kevin; Mally, Angela

2015-01-01

Altered expression of tumor suppressor genes and oncogenes, which is regulated in part at the level of DNA methylation, is an important event involved in non-genotoxic carcinogenesis. This may serve as a marker for early detection of non-genotoxic carcinogens. Therefore, we evaluated the effects of non-genotoxic hepatocarcinogens, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), hexachlorobenzene (HCB), methapyrilene (MPY) and male rat kidney carcinogens, d-limonene, p-dichlorobenzene (DCB), chloroform and ochratoxin A (OTA) on global and CpG island promoter methylation in their respective target tissues in rats. No significant dose-related effects on global DNA hypomethylation were observed in tissues of rats compared to vehicle controls using LC–MS/MS in response to short-term non-genotoxic carcinogen exposure. Initial experiments investigating gene-specific methylation using methylation-specific PCR and bisulfite sequencing, revealed partial methylation of p16 in the liver of rats treated with HCB and TCDD. However, no treatment related effects on the methylation status of Cx32, e-cadherin, VHL, c-myc, Igfbp2, and p15 were observed. We therefore applied genome-wide DNA methylation analysis using methylated DNA immunoprecipitation combined with microarrays to identify alterations in gene-specific methylation. Under the conditions of our study, some genes were differentially methylated in response to MPY and TCDD, whereas d-limonene, DCB and chloroform did not induce any methylation changes. 90-day OTA treatment revealed enrichment of several categories of genes important in protein kinase activity and mTOR cell signaling process which are related to OTA nephrocarcinogenicity. - Highlights: • Studied non-genotoxic carcinogens caused no change on global DNA hypomethylation. • d-Limonene, DCB and chloroform did not show any genome-wide methylation changes. • Some genes were differentially methylated in response to MPY, TCDD and OTA. • Protein kinase activity

Influence of iron plaque on uptake and accumulation of Cd by rice (Oryza sativa L.) seedlings grown in soil.

Science.gov (United States)

Liu, Houjun; Zhang, Junling; Christie, Peter; Zhang, Fusuo

2008-05-15

Iron plaque is ubiquitously formed on the root surfaces of rice. However, little is known about the role of iron plaque in Cd movement from soil to the plant aboveground parts. A pot experiment was conducted to investigate the influence of iron plaque in Cd uptake and accumulation by rice seedlings in soil. Rice seedlings were pre-cultivated in solution culture for 16 days. Two seedlings were transplanted in a nylon bag containing no substrate but surrounded by soil amended with Fe and Cd combined at rates of 0, 1, or 2 g Fe kg(-1) and 0, 2.0, or 10 mg Cd kg(-1) soil. Fe was added to induce different amounts of iron plaque, and Cd to simulate Cd-polluted soils. Plants were grown for a further 43 days and then harvested. The length of the longest leaf and SPAD values of the newly mature leaves were measured during plant growth. Fe and Cd concentrations were determined in dithionite-citrate-bicarbonate (DCB) soil extracts and in plant roots and shoots. Shoot and root dry weights were significantly affected by Fe supply level but not by added Cd. Root dry weight declined with increasing Fe supply but shoot dry weight decreased at 2 g Fe kg(-1) and increased at 1 g Fe kg(-1) (except at 2 mg Cd kg(-1)). The length of the longest leaf and SPAD values of the newly mature leaves were significantly affected by plant growth stage and added Fe and Cd. Fe tended to diminish the negative effect of Cd on these two parameters. Cd concentrations in DCB extracts increased with increasing Cd and Fe supply. In contrast, external Fe supply markedly reduced shoot and root Cd concentrations and there was generally no significant difference between the two Fe supply levels. Shoot and root Cd concentrations increased with increasing Cd addition. Root Cd concentrations were negatively correlated with root Fe concentrations. The proportion of Cd in DCB extracts was significantly lower than in roots or shoots. The results indicate that enhanced Fe uptake by plants can diminish the negative

Combined use of directional atherectomy and drug-coated balloon for the endovascular treatment of common femoral artery disease: immediate and one-year outcomes.

Science.gov (United States)

Cioppa, Angelo; Stabile, Eugenio; Salemme, Luigi; Popusoi, Grigore; Pucciarelli, Armando; Iacovelli, Fortunato; Arcari, Antonella; Coscioni, Enrico; Trimarco, Bruno; Esposito, Giovanni; Tesorio, Tullio

2017-02-20

Surgical endarterectomy is the therapy of choice for atherosclerotic common femoral artery (CFA) obstruction. Recently, some large single-centre series have shown encouraging results for the percutaneous treatment of CFA obstructions. The purpose of this study was to evaluate the safety, feasibility, and one-year efficacy of the endovascular treatment of CFA obstructions with combined use of directional atherectomy (DA) and a paclitaxel-coated balloon (DCB). Between January 2012 and July 2014, 30 consecutive patients with severely calcified obstructions of the common femoral artery were treated in our centre using DA followed by DCB dilatation. Provisional stenting was allowed in the case of a suboptimal result. Twenty cases (66%) were isolated CFA interventions, whereas five (17%) and five (17%) also involved inflow and outflow vessels, respectively. Chronic total CFA occlusions (CTO) were recanalised in six cases (20%). Procedural success was achieved in all cases; stenting was needed in three cases (10%). At one year, restenosis and target lesion revascularisation were observed in two of 30 (6.6%) and one of 30 (3.3%) patients, respectively. The secondary patency rate was 96.7%. This single-centre prospective study suggests that the combined use of DA and DCB is a safe and effective alternative to surgery, a treatment option for common femoral artery lesions and provides encouraging results in this setting.

Interest Rate Liberalization, Financial Development and Economic ...

African Journals Online (AJOL)

debate the impact of financial sector on economic growth; most of them ..... financial development, introduces domestic credit to the banking public, DCB, ...... Hysteresis in Unemployment: ... Obute, C., Adyorough, A., & Itodo, A.I. (2012).

Microstructural control over soluble pentacene deposited by capillary pen printing for organic electronics.

Science.gov (United States)

Lee, Wi Hyoung; Min, Honggi; Park, Namwoo; Lee, Junghwi; Seo, Eunsuk; Kang, Boseok; Cho, Kilwon; Lee, Hwa Sung

2013-08-28

Research into printing techniques has received special attention for the commercialization of cost-efficient organic electronics. Here, we have developed a capillary pen printing technique to realize a large-area pattern array of organic transistors and systematically investigated self-organization behavior of printed soluble organic semiconductor ink. The capillary pen-printed deposits of organic semiconductor, 6,13-bis(triisopropylsilylethynyl) pentacene (TIPS_PEN), was well-optimized in terms of morphological and microstructural properties by using ink with mixed solvents of chlorobenzene (CB) and 1,2-dichlorobenzene (DCB). Especially, a 1:1 solvent ratio results in the best transistor performances. This result is attributed to the unique evaporation characteristics of the TIPS_PEN deposits where fast evaporation of CB induces a morphological evolution at the initial printed position, and the remaining DCB with slow evaporation rate offers a favorable crystal evolution at the pinned position. Finally, a large-area transistor array was facilely fabricated by drawing organic electrodes and active layers with a versatile capillary pen. Our approach provides an efficient printing technique for fabricating large-area arrays of organic electronics and further suggests a methodology to enhance their performances by microstructural control of the printed organic semiconducting deposits.

Drug-Coated Balloon Angioplasty: A Novel Treatment for Pulmonary Artery In-Stent Stenosis in a Patient with Williams Syndrome.

Science.gov (United States)

Cohen, Jennifer L; Glickstein, Julie S; Crystal, Matthew A

2017-12-01

A 20-month-old boy with Williams syndrome had undergone multiple surgical and catheter-based interventions for resistant peripheral pulmonary arterial stenoses with eventual bilateral stent placement and conventional balloon angioplasty. He persistently developed suprasystemic right ventricular (RV) pressure. Angioplasty with a drug-coated balloon (DCB) was performed for in-stent restenosis and to remodel his distal pulmonary vessels bilaterally. This resulted in immediate improvement in the in-stent stenosis and resultant decrease in RV pressure. Follow-up catheterization two months later continued to show long-lasting improvement in the in-stent stenosis. We hypothesize that the anti-proliferative effects of DCBs may be of benefit in the arteriopathy associated with Williams syndrome. We report this as a novel use of a DCB in the pulmonary arterial circulation in a patient with Williams syndrome.

Mode I type delamination fracture toughness of YBCO coated conductor with additional Cu layer

International Nuclear Information System (INIS)

Miyazato, T.; Hojo, M.; Sugano, M.; Adachi, T.; Inoue, Y.; Shikimachi, K.; Hirano, N.; Nagaya, S.

2011-01-01

A fracture toughness test method was developed for a YBCO coated conductor with an additional Cu layer. Mode I type tests were carried out using double cantilever beam (DCB) specimens. Delamination propagated into the YBCO layer, and sometimes reached the Ag/YBCO interface. The fracture toughness for YBCO was about 10 J/m 2 . That for Ag/YBCO interface was about 100 J/m 2 . Although interlaminar fracture at a YBa 2 Cu 3 O 7-δ (YBCO)/CeO 2 interface was reported for YBCO coated conductors, this has not yet been investigated by a fracture mechanical approach. In the present study, we developed a mode I type fracture toughness test method for a YBCO coated conductor with an additional Cu layer using double cantilever beam (DCB) specimens. Fracture mechanism was investigated by microscopic observation by a scanning electron microscope (SEM), together with composition analysis by an energy dispersive X-ray spectroscope (EDS). A pre-crack introduced at the YBCO/CeO 2 interface deviated from the interface, and propagated into the YBCO layer, and sometimes reached the Ag/YBCO interface. The fracture toughness, G R , for YBCO and the Ag/YBCO interface was evaluated to be 7-10 J/m 2 and 80-120 J/m 2 , respectively. The complex stress intensity factor ratio, K 2 /K 1 , at YBCO/CeO 2 interface was evaluated to be -0.19, and this ratio controlled the formation of microcracks in the YBCO layer. The main crack propagated into the YBCO layer accompanied with the formation of microcracks.

SCC evaluation of candidate container alloys by DCB method

International Nuclear Information System (INIS)

Roy, A.K.; Freeman, D.C.; Lum, B.Y.; Spragge, M.K.

1999-01-01

The authors use a solid mechanics approach to investigate hydride formation and cracking in zirconium-niobium alloys used in the pressure tubes of CANDU nuclear reactors. In this approach, the forming hydride is assumed to be purely elastic and its volume dilation is accommodated by elasto-plastic deformation of the surrounding matrix material. The energetics of the hydride formation is revisited and the terminal solid solubility of hydrogen in solution is defined on the basis of the total elasto-plastic work done on the system by the forming hydride and the external loads. Hydrogen diffusion and probabilistic hydride formation coupled with the material deformation are modeled at a blunting crack tip under plane strain loading. A full transient finite element analysis allows for numerical monitoring of the development and expansion of the hydride zone as the externally applied loads increase. Using a Griffith fracture criterion for fracture limitiation, the reduced fracture resistance of the alloy can be predicted and the factors affecting fracture toughness quantified

The application of J integral to measure cohesive laws in materials undergoing large scale yielding

DEFF Research Database (Denmark)

Sørensen, Bent F.; Goutianos, Stergios

2015-01-01

We explore the possibility of determining cohesive laws by the J-integral approach for materials having non-linear stress-strain behaviour (e.g. polymers and composites) by the use of a DCB sandwich specimen, consisting of stiff elastic beams bonded to the non-linear test material, loaded with pure...... bending moments. For a wide range of parameters of the non-linear material, the plastic unloading during crack extension is small, resulting in J integral values (fracture resistance) that deviate maximum 15% from the work of the cohesive traction. Thus the method can be used to extract the cohesive laws...... directly from experiments without any presumption about their shape. Finally, the DCB sandwich specimen was also analysed using the I integral to quantify the overestimation of the steady-state fracture resistance obtained using the J integral based method....

Extent and Durability of Contamination of Groundwater and Water Works With The Pesticide Metabolite Bam (2,6 -dichlorbenzamide) Evaluated For Representative Aquifers In Denmark

Science.gov (United States)

Jørgensen, Peter R.; Clausen, Liselotte; Larsen, Flemming

The pesticide metabolite BAM (2,6-dichlorbenzamide) is the most frequently found pesticide contaminant in Danish groundwater. In 1999 BAM was found in 26% of Danish water supply wells and the drinking water standard (0.1 µg/L) was exceeded in 11% of the wells. BAM is a metabolite from the active ingredient dichlobenil (DCB), which was used for non-agricultural total weed protection during 1966 ­ 1997. By using the numerical codes FRAC3Dvs and MODFLOW/MT3D it is the aim of the study to evaluate the extent and durability of the BAM pollution in Danish groundwater and to recommend planning strategies to avoid or minimize BAM in future water supply. The modeling was based on the total amount sold of the DCB (29.000 ton/year) combined with data for sorption and degradation of the DCB and BAM measured from comprehensive laboratory experiments with soil material representing root zone and main aquifer soil types in Denmark. As a main result the laboratory experiments revealed that BAM was only very slowly degraded in the root zone, while no degradation was observed in the sub-soil environments. Combining these model in-put data with representative data for the main aquifer types and overriding fractured clay aquitards, the modeling indicates that more than 99% of infiltrated dichlobenile has been transformed to its metabolite BAM (approximately 500 tons in total), and that currently (year 2001) approximately 100% of this compound appears widely in the groundwater and/or in the above aquitards. The modeling shows that the BAM pollution will appear in the groundwater with a high frequency in extensive parts of Denmark during the following 20 years to more than 100 years. The highest current BAM concentrations, but however also the shortest durability of the BAM pollution, will occur in contaminated aquifers, which are not covered with clay layers. Short durability in such areas is furthermore dependent on the lack of further up-stream BAM sources. The modeling moreover

Kwantificatie van PCB-componenten in krachtvoeders

NARCIS (Netherlands)

Mazijk, van R.J.; Munsteren, van A.J.; Tuinstra, L.G.M.Th.

1981-01-01

Met behulp van individuele chloorbifenylstandaarden is het PCB-gehalte van een aantal krachtvoeders bepaald, waarbij voor de onbekende componenten een geschatte waarde is gebruikt. Uit deze gehalten is met behulp van omrekeningsfactoren de theoretische DCB-opbrengst bij perchloreren berekend. Dit

Critical assessment of the mandrel peel test for fiber reinforced thermoplastic laminates

NARCIS (Netherlands)

Grouve, Wouter Johannes Bernardus; Warnet, Laurent; Akkerman, Remko

2013-01-01

The applicability of the mandrel peel test for thermoplastic composites was investigated experimentally by comparing the fracture toughness to the values obtained by the double cantilever beam (DCB) and end loaded split (ELS) beam test. Two laminates were considered: a unidirectionally carbon-PPS

Perchlorering van PCB-extracten van paling : verificatie van Decachloorbifenyl m.b.v. massa spectrometrie

NARCIS (Netherlands)

Traag, W.A.; Mazijk, van R.J.; Tuinstra, L.G.M.Th.

1980-01-01

De gaschromatografische analyse van Decachloorbifenyl (DCB) wordt meestal uitgevoerd op een korte gepakte kolom, waardoor het mogelijk is een groot aantal monsters in een kort tijdsbestek te analyseren. Om eventuele interferentie aan te tonen werd de analyse uitgevoerd op een capillaire kolom met

The Synthesis of Carbon Nanomaterials using Chlorinated ...

African Journals Online (AJOL)

The effect of chlorine on the morphology of carbon nanotubes (CNTs) prepared from a Fe-Co/CaCO3 catalyst was investigated using chlorobenzene (CB), dichlorobenzene (DCB), trichlorobenzene (TCB), dichloroethane (DCE), trichloroethane (TCE) and tetrachloroethane (TTCE) as chlorine sources using a catalytic ...

A Practical Test Method for Mode I Fracture Toughness of Adhesive Joints with Dissimilar Substrates

Energy Technology Data Exchange (ETDEWEB)

Boeman, R.G.; Erdman, D.L.; Klett, L.B.; Lomax, R.D.

1999-09-27

A practical test method for determining the mode I fracture toughness of adhesive joints with dissimilar substrates will be discussed. The test method is based on the familiar Double Cantilever Beam (DCB) specimen geometry, but overcomes limitations in existing techniques that preclude their use when testing joints with dissimilar substrates. The test method is applicable to adhesive joints where the two bonded substrates have different flexural rigidities due to geometric and/or material considerations. Two specific features discussed are the use of backing beams to prevent substrate damage and a compliance matching scheme to achieve symmetric loading conditions. The procedure is demonstrated on a modified DCB specimen comprised of SRIM composite and thin-section, e-coat steel substrates bonded with an epoxy adhesive. Results indicate that the test method provides a practical means of characterizing the mode I fracture toughness of joints with dissimilar substrates.

Volatile organic compounds and pulmonary function in the Third National Health and Nutrition Examination Survey, 1988-1994.

Science.gov (United States)

Elliott, Leslie; Longnecker, Matthew P; Kissling, Grace E; London, Stephanie J

2006-08-01

Volatile organic compounds (VOCs) are present in much higher concentrations indoors, where people spend most of their time, than outdoors and may have adverse health effects. VOCs have been associated with respiratory symptoms, but few studies address objective respiratory end points such as pulmonary function. Blood levels of VOCs may be more indicative of personal exposures than are air concentrations; no studies have addressed their relationship with respiratory outcomes. We examined whether concentrations of 11 VOCs that were commonly identified in blood from a sample of the U.S. population were associated with pulmonary function. We used data from 953 adult participants (20-59 years of age) in the Third National Health and Nutrition Examination Survey (1988-1994) who had VOC blood measures as well as pulmonary function measures. Linear regression models were used to evaluate the relationship between 11 VOCs and measures of pulmonary function. After adjustment for smoking, only 1,4-dichlorobenzene (1,4-DCB) was associated with reduced pulmonary function. Participants in the highest decile of 1,4-DCB concentration had decrements of -153 mL [95% confidence interval (CI) , -297 to -8] in forced expiratory volume in 1 sec and -346 mL/sec (95% CI, -667 to -24) in maximum mid-expiratory flow rate, compared with participants in the lowest decile. Exposure to 1,4-DCB, a VOC related to the use of air fresheners, toilet bowl deodorants, and mothballs, at levels found in the U.S. general population, may result in reduced pulmonary function. This common exposure may have long-term adverse effects on respiratory health.

The concept of fatigue fracture toughness in fatigue delamination growth behavior

NARCIS (Netherlands)

Yao, L.; Alderliesten, R.C.; Benedictus, R.

2015-01-01

This paper provides a study on mode I fatigue delamination growth in composite laminates using energy principles. Experimental data has been obtained from fatigue tests conducted on Double Cantilever Beam (DCB) specimens at various stress ratios. A concept of fatigue fracture toughness is proposed

Woven fabric composites: Can we peel it?

NARCIS (Netherlands)

Sacchetti, Francisco; Grouve, Wouter Johannes Bernardus; Warnet, Laurent; Villegas, I. Fernandez

2016-01-01

The present work focuses on the applicability of the mandrel peel test to quantify the fracture toughness of woven fabric Carbon/PEEK composites. For this purpose, the mandrel peel test was compared to the standardized DCB test. Unstable crack propagation (stick-slip) was observed in both testing

Acoustic emission for interlaminar toughness testing of CFRP: Evaluation of the crack growth due to burst analysis

Czech Academy of Sciences Publication Activity Database

Lissek, F.; Haegerb, A.; Knoblauch, V.; Hloch, Sergej; Pude, F.; Kaufeld, M.

2018-01-01

Roč. 136, č. 1 (2018), s. 55-62 ISSN 1359-8368 Institutional support: RVO:68145535 Keywords : DCB * interlaminar toughness testing * acoustic emission * CFRP * burst analysis Subject RIV: JQ - Machines ; Tools Impact factor: 4.727, year: 2016 http://www.sciencedirect.com/science/article/pii/S1359836817313720

Bonding characteristics of glass seal/metallic interconnect for SOFC applications: Comparative study on chemical and mechanical properties of the interface

DEFF Research Database (Denmark)

Abdoli, Hamid; Alizadeh, Parvin; Boccaccini, Dino

fracture energies is double cantilever beam (DCB) test. The method allows to measure the crack-growth resistance of these materials to be able to use fracture mechanics design methods. Stable crack growth is necessary to get reliable and unambiguous fracture toughness data. If the fracture toughness values...

Acoustic emission for interlaminar toughness testing of CFRP: Evaluation of the crack growth due to burst analysis

Czech Academy of Sciences Publication Activity Database

Lissek, F.; Haegerb, A.; Knoblauch, V.; Hloch, Sergej; Pude, F.; Kaufeld, M.

2018-01-01

Roč. 136, č. 1 (2018), s. 55-62 ISSN 1359-8368 Institutional support: RVO:68145535 Keywords : DCB * interlaminar toughness testing * acoustic emission * CFRP * burst analysis Subject RIV: JQ - Machines ; Tools Impact factor: 4.727, year: 2016 http://www. science direct.com/ science /article/pii/S1359836817313720

Influence of the Hybrid Combination of Multiwalled Carbon Nanotubes and Graphene Oxide on Interlaminar Mechanical Properties of Carbon Fiber/Epoxy Laminates

Science.gov (United States)

Rodríguez-González, J. A.; Rubio-González, C.; Jiménez-Mora, M.; Ramos-Galicia, L.; Velasco-Santos, C.

2017-10-01

An effective strategy to improve the mode I and mode II interlaminar fracture toughness (G IC and G IIC ) of unidirectional carbon fiber/epoxy (CF/E) laminates using a hybrid combination of multiwalled carbon nanotubes (MWCNTs) and graphene oxide (GO) is reported. Double cantilever beam (DCB) and end notched flexure (ENF) tests were conducted to evaluate the G IC and G IIC of the CF/E laminates fabricated with sprayed MWCNTs, GO and MWCNTs/GO hybrid. Scanning electron microscopy was employed to observe the fracture surfaces of tested DCB and ENF specimens. Experimental results showed the positive effect on the G IC and G IIC by 17% and 14% improvements on CF/E laminates with 0.25 wt.% MWCNTs/GO hybrid content compared to the neat CF/E. Also, the interlaminar shear strength value was increased for MWCNTs/GO-CF/E laminates. A synergetic effect between MWCNTs and GO resulted in improved interlaminar mechanical properties of CF/E laminates made by prepregs.

Constant Cutting Force Control for CNC Machining Using Dynamic Characteristic-Based Fuzzy Controller

Directory of Open Access Journals (Sweden)

Hengli Liu

2015-01-01

Full Text Available This paper presents a dynamic characteristic-based fuzzy adaptive control algorithm (DCbFACA to avoid the influence of cutting force changing rapidly on the machining stability and precision. The cutting force is indirectly obtained in real time by monitoring and extraction of the motorized spindle current, the feed speed is fuzzy adjusted online, and the current was used as a feedback to control cutting force and maintain the machining process stable. Different from the traditional fuzzy control methods using the experience-based control rules, and according to the complex nonlinear characteristics of CNC machining, the power bond graph method is implemented to describe the dynamic characteristics of process, and then the appropriate variation relations are achieved between current and feed speed, and the control rules are optimized and established based on it. The numerical results indicated that DCbFACA can make the CNC machining process more stable and improve the machining precision.

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African Journals Online (AJOL)

GREGORY

2010-09-13

Sep 13, 2010 ... Piper aduncum. Phytochemistry, 48: 1075-1077. Navickiene HMD, Morandim AA, Alécio AC, Regasini LO, Bergamo. DCB, Telascrea M, Cavalheiro AJ, Lopes MN, Bolzani VS, Furlan M,. Marques MOM, Young MCM, Kato MJ (2006). Composition and antifungal activity of essential oils from Piper aduncum, ...

Volatile Organic Compounds and Pulmonary Function in the Third National Health and Nutrition Examination Survey, 1988–1994

Science.gov (United States)

Elliott, Leslie; Longnecker, Matthew P.; Kissling, Grace E.; London, Stephanie J.

2006-01-01

Background Volatile organic compounds (VOCs) are present in much higher concentrations indoors, where people spend most of their time, than outdoors and may have adverse health effects. VOCs have been associated with respiratory symptoms, but few studies address objective respiratory end points such as pulmonary function. Blood levels of VOCs may be more indicative of personal exposures than are air concentrations; no studies have addressed their relationship with respiratory outcomes. Objective We examined whether concentrations of 11 VOCs that were commonly identified in blood from a sample of the U.S. population were associated with pulmonary function. Methods We used data from 953 adult participants (20–59 years of age) in the Third National Health and Nutrition Examination Survey (1988–1994) who had VOC blood measures as well as pulmonary function measures. Linear regression models were used to evaluate the relationship between 11 VOCs and measures of pulmonary function. Results After adjustment for smoking, only 1,4-dichlorobenzene (1,4-DCB) was associated with reduced pulmonary function. Participants in the highest decile of 1,4-DCB concentration had decrements of −153 mL [95% confidence interval (CI), −297 to −8] in forced expiratory volume in 1 sec and −346 mL/sec (95% CI, −667 to −24) in maximum mid-expiratory flow rate, compared with participants in the lowest decile. Conclusions Exposure to 1,4-DCB, a VOC related to the use of air fresheners, toilet bowl deodorants, and mothballs, at levels found in the U.S. general population, may result in reduced pulmonary function. This common exposure may have long-term adverse effects on respiratory health. PMID:16882527

Enhanced performance of P3HT/(PCBM:ZnO:TiO{sub 2}) blend based hybrid organic solar cells

Energy Technology Data Exchange (ETDEWEB)

Ikram, M., E-mail: mianraj.1981@gmail.com [Solar Application Lab, Department of Physics, Government College University Lahore, 54000 Pakistan (Pakistan); Murray, R. [Department of Physics and Astronomy, University of Delaware, Delaware 19716 (United States); Imran, M. [Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, 29 Zhongguancun East Road, Haidian District, Beijing 100190 (China); Ali, S. [Solar Application Lab, Department of Physics, Government College University Lahore, 54000 Pakistan (Pakistan); Shah, S.Ismat [Department of Materials Science and Engineering, University of Delaware, Delaware 19716 (United States); Department of Physics and Astronomy, University of Delaware, Delaware 19716 (United States)

2016-03-15

Highlights: • We fabricated hybrid bulk heterojunction organic solar cells. • TiO{sub 2} and ZnO nanoparticles replace PCBM with fixed amount of P3HT in active layer • PCE was significantly improved by the introduction of TiO{sub 2} and ZnO. • A possible route toward low-cost OPV. • To the best of my knowledge, this work is the first time going to report. - Abstract: Quaternary blend hybrid organic solar cells enjoy both an increased light absorption range and an easy method to fabricate because of the simple structure. In this study effects of mixing inorganic metal oxides (ZnO and TiO{sub 2}) nanoparticles to the active layer of organic photovoltaics devices were investigated. The active layer primarily consists of various ratios of electron donor poly (3-hexylthiophene) (P3HT) and an electron acceptor [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) together with nanostructured ZnO and TiO{sub 2} dispersed in chlorobenzene (CB) and 1,2-dichlorobenzene (DCB). The ratio of PCBM to nanoparticles was varied keeping the ratio of P3HT to acceptor material constant. Mixing of nanoparticle plays a significant role in the resulting power conversion efficiency (PCE) of the devices. An increased PCE for ZnO/TiO{sub 2} doped devices can be attributed to increased absorption in the visible region and enhanced charge collection due to the percolation networks formed by metal oxides nanoparticles.

Fate of sulfamethoxazole, 4-nonylphenol, and 17beta-estradiol in groundwater contaminated by wastewater treatment plant effluent.

Science.gov (United States)

Barber, Larry B; Keefe, Steffanie H; Leblanc, Denis R; Bradley, Paul M; Chapelle, Francis H; Meyer, Michael T; Loftin, Keith A; Kolpin, Dana W; Rubio, Fernando

2009-07-01

Organic wastewater contaminants (OWCs) were measured in samples collected from monitoring wells located along a 4.5-km transect of a plume of groundwater contaminated by 60 years of continuous rapid infiltration disposal of wastewater treatment plant effluent. Fifteen percent of the 212 OWCs analyzed were detected, including the antibiotic sulfamethoxazole (SX), the nonionic surfactant degradation product 4-nonylphenol (NP), the solvent tetrachloroethene (PCE), and the disinfectant 1,4-dichlorobenzene (DCB). Comparison of the 2005 sampling results to data collected from the same wells in 1985 indicates that PCE and DCB are transported more rapidly in the aquiferthan NP, consistent with predictions based on compound hydrophobicity. Natural gradient in situ tracer experiments were conducted to evaluate the subsurface behavior of SX, NP, and the female sex hormone 17beta-estradiol (E2) in two oxic zones in the aquifer: (1) a downgradient transition zone at the interface between the contamination plume and the overlying uncontaminated groundwater and (2) a contaminated zone located beneath the infiltration beds, which have not been loaded for 10 years. In both zones, breakthrough curves for the conservative tracer bromide (Br-) and SX were nearly coincident, whereas NP and E2 were retarded relative to Br- and showed mass loss. Retardation was greater in the contaminated zone than in the transition zone. Attenuation of NP and E2 in the aquifer was attributed to biotransformation, and oxic laboratory microcosm experiments using sediments from the transition and contaminated zones show that uniform-ring-labeled 14C 4-normal-NP was biodegraded more rapidly 130-60% recovered as 14CO2 in 13 days) than 4-14C E2 (20-90% recovered as 14CO2 in 54 days). There was little difference in mineralization potential between sites.

Fate of sulfamethoxazole, 4-nonylphenol, and 17β-estradiol in groundwater contaminated by wastewater treatment plant effluent

Science.gov (United States)

Barber, Larry B.; Keefe, Steffanie H.; LeBlanc, Denis R.; Bradley, Paul M.; Chapelle, Francis H.; Meyer, Michael T.; Loftin, Keith A.; Koplin, Dana W.; Rubio, Fernando

2009-01-01

Organic wastewater contaminants (OWCs) were measured in samples collected from monitoring wells located along a 4.5-km transect of a plume of groundwater contaminated by 60 years of continuous rapid infiltration disposal of wastewater treatment plant effluent. Fifteen percent of the 212 OWCs analyzed were detected, including the antibiotic sulfamethoxazole (SX), the nonionic surfactant degradation product 4-nonylphenol (NP), the solvent tetrachloroethene (PCE), and the disinfectant 1,4-dichlorobenzene (DCB). Comparison of the 2005 sampling results to data collected from the same wells in 1985 indicates that PCE and DCB are transported more rapidly in the aquifer than NP, consistent with predictions based on compound hydrophobicity. Natural gradient in situ tracer experiments were conducted to evaluate the subsurface behavior of SX, NP, and the female sex hormone 17β-estradiol (E2) in two oxic zones in the aquifer: (1) a downgradient transition zone at the interface between the contamination plume and the overlying uncontaminated groundwater and (2) a contaminated zone located beneath the infiltration beds, which have not been loaded for 10 years. In both zones, breakthrough curves for the conservative tracer bromide (Br−) and SX were nearly coincident, whereas NP and E2 were retarded relative to Br− and showed mass loss. Retardation was greater in the contaminated zone than in the transition zone. Attenuation of NP and E2 in the aquifer was attributed to biotransformation, and oxic laboratory microcosm experiments using sediments from the transition and contaminated zones show that uniform-ring-labeled 14C 4-normal-NP was biodegraded more rapidly (30−60% recovered as 14CO2 in 13 days) than 4-14C E2 (20−90% recovered as 14CO2in 54 days). There was little difference in mineralization potential between sites.

The dynamics of low-chlorinated benzenes in a pilot-scale constructed wetland and a hydroponic plant root mat treating sulfate-rich groundwater.

Science.gov (United States)

Chen, Zhongbing; Kuschk, Peter; Paschke, Heidrun; Kästner, Matthias; Köser, Heinz

2015-03-01

A rarely used hydroponic plant root mat filter (PRMF, of 6 m(2)) and a horizontal subsurface flow constructed wetland (HSSF CW, of 6 m(2)), operating in continuous flow and discontinuous outflow flushing modes, were investigated for treating sulfate-rich and organic carbon-lean groundwater contaminated with monochlorobenzene (MCB); 1,2-dichlorobenzene (1,2-DCB); 1,4-dichlorobenzene (1,4-DCB); and 2-chlorotoluene. Whereas the mean inflow loads ranged from 1 to 247 mg m(-2) days(-1), the range of mean inflow concentrations of the chlorobenzenes recorded over a period of 7 months was within 0.04 and 8 mg L(-1). A hydraulic surface loading rate of 30 L m(-2) days(-1) was obtained in both systems. The mean load removal efficiencies were found to vary between 87 and 93 % in the PRMF after a flow path of 4 m, while the removal efficiencies were found to range between 46 and 70 % and 71 to 73 % in the HSSF CW operating in a continuous flow mode and a discontinuous outflow flushing mode, respectively. Seasonal variations in the removal efficiencies were observed for all low-chlorinated hydrocarbons both in the PRMF and the HSSF CW, whereby the highest removal efficiencies were reached during the summer months. Sulfide formation occurred in the organic carbon-lean groundwater particularly in summer, which is probably due to the plant-derived organic carbon that fostered the microbial dissimilatory sulfate reduction. Higher redox potential in water was observed in the PRMF. In conclusion, the PRMF could be an option for the treatment of water contaminated with compounds which in particular need oxic conditions for their microbial degradation, such as in the case of low-chlorinated benzenes.

Influencia del envejecimiento higrotérmico en el comportamiento a fractura de compuestos de matriz termoplástica

Directory of Open Access Journals (Sweden)

Zenasni, R.

2004-04-01

Full Text Available Aging was carried out by introducing the materials into a climatic chamber under appropriate conditions of temperature, humidity and time. The materials are made of two types of weaving (2/2 Twill, 8H Satin glass fibre, and (8H Satin carbon fibre. The matrix was polyetherimide(PEI. In order to characterize the interlaminar fracture a mechanical test was carried out using the mode I Double Cantilever Beam (DCB and mode II End Notched Fixed (ENF tests. The analysis consists of knowing the different failure mechanisms which have generated the hygrothermal aging.

En este trabajo se realiza un estudio sobre la influencia del envejecimiento higrotérmico en el comportamiento a fractura interlaminar de tres tipos de compuestos, dos de ellos reforzados con tejido de fibra de vidrio(2/2 Twill, y 8H Satin y otro con fibra de carbono (8H Satin . El envejecimiento se realizó manteniendo, durante diferentes periodos de tiempo, probetas en una cámara climática bajo unas determinadas condiciones de temperatura y humedad relativa. La determinación de la tenacidad a fractura interlaminar se realizó utilizando probetas de modos I (DCB y II (ENF. El análisis realizado consistió en poner de manifiesto los diferentes mecanismos de rotura a fractura que se generan tras someter las probetas a la exposición higrotérmica. De los resultados de los ensayos se concluye un diferente comportamiento a fractura según el refuerzo existente y también a igual refuerzo, según la trama del tejido.

Biases in GNSS-Data Processing

Science.gov (United States)

Schaer, S. C.; Dach, R.; Lutz, S.; Meindl, M.; Beutler, G.

2010-12-01

Within the Global Positioning System (GPS) traditionally different types of pseudo-range measurements (P-code, C/A-code) are available on the first frequency that are tracked by the receivers with different technologies. For that reason, P1-C1 and P1-P2 Differential Code Biases (DCB) need to be considered in a GPS data processing with a mix of different receiver types. Since the Block IIR-M series of GPS satellites also provide C/A-code on the second frequency, P2-C2 DCB need to be added to the list of biases for maintenance. Potential quarter-cycle biases between different phase observables (specifically L2P and L2C) are another issue. When combining GNSS (currently GPS and GLONASS), careful consideration of inter-system biases (ISB) is indispensable, in particular when an adequate combination of individual GLONASS clock correction results from different sources (using, e.g., different software packages) is intended. Facing the GPS and GLONASS modernization programs and the upcoming GNSS, like the European Galileo and the Chinese Compass, an increasing number of types of biases is expected. The Center for Orbit Determination in Europe (CODE) is monitoring these GPS and GLONASS related biases for a long time based on RINEX files of the tracking network of the International GNSS Service (IGS) and in the frame of the data processing as one of the global analysis centers of the IGS. Within the presentation we give an overview on the stability of the biases based on the monitoring. Biases derived from different sources are compared. Finally, we give an outlook on the potential handling of such biases with the big variety of signals and systems expected in the future.

Radiation degradation of aromatic pollutants exit in wastewater and ph dependence

International Nuclear Information System (INIS)

Takriti, S.

2002-12-01

The effect of gamma radiation on the degradation of phenol (hydroxybenzene), resorcinol (1,3 dihydroxybenzen) and hydroquinone (1,4 dihydroxybenzen) exit in waste water was investigated. The concentrations of these pollutants as well as the irradiated solution ph were studied. The results showed that the phenol is very resistance against the radiation doses comparing the other phenol compounds. Phenol was also a product of radiolysis of resorcinol and hydroquinone. On the other hand, the acid phase of the irradiation sample increased the degradation rate of pollutants. Spectrophotometer (UV-VIS) and chromatography (HPLC) were used to monitor the analysis of the radiation product solution. The results illustrated the existing of many substances such as organic alcohol, aldehyde, ketone and acidic functional groups as a final radiation products. The degradation of benzene, monochlorobenzene (CB) and 1,2 dichlorobenzene (1,2 DCB) exit in waste water by gamma irradiation was investigated. The effect of the irradiated solution composition was studied. The results showed that the benzene is very resistance against the radiation doses comparing to other chlorobenzene. However, the existence of oxidizing substances in the irradiation phase leads to increase the degradation rate of pollutants. The dechlorination of CB and 1,2 DCB that is a result of the hydrated electron reaction with studied compounds was observed. Chromatography (HPLC) and spectrophotometer (UV-VIS) were used to monitor the analysis of the radiation product solution. The results illustrated the existing of many species as a final radiation product. On the other, the irradiation phase containing scavengers such as methanol and ethanol requires large doses to decompose the pollutants, while the oxidizing phase accelerates the degradation. (author)

Critical experiments, measurements and analyses to establish a crack arrest methodology for nuclear pressure vessel steels. Task 62. Second annual progress report, 1 July 1975 to 30 June 1976

International Nuclear Information System (INIS)

Hahn, G.T.; Gehlen, P.C.; Hoagland, R.G.; Marschall, C.W.; Kanninen, M.F.; Popelar, C.; Rosenfield, A.R.

1976-10-01

Developments of the theory, the analyses and the materials characterization for assessments of crack arrest in heavy walled nuclear pressure vessels are described. A two-dimensional, dynamic, finite difference analysis of crack propagation and arrest, including inertia forces and thermal stresses is derived. The analysis is used to treat run-arrest events in DCB- and SEN-specimens. Calculations based on the one-dimensional analysis are compared with detailed measurements of run-arrest in two polymeric materials. The agreements between calculations and experiments support the dynamic, energy conservation theory of crack arrest. Implications of a K/sub ID/-crack velocity curve with a negative slope are examined. The quantity K/sub Im/, the minimum propagating crack toughness, is identified as the crack arrest material property for engineering applications. Considerations entering the design of a crack arrest property measuring procedure, including specimen shape, size, thickness and the crack jump are discussed. The influence of side grooves on the propensity for crack branching is examined. Compliance measurements for rectangular DCB-specimens are presented and analyzed. Energy losses arising from damping remote from the crack tip in an A533B steel DCB specimen are described, and classed as negligible. Interactions between test pieces and the loading system are examined. A simplified procedure for measuring K/sub D/-, K/sub m/-, and K/sub a/-values, based on the dynamic analysis of the crack length at arrest is demonstrated. Measurements of K/sub D/ at temperatures in the range (NDT-66)C to (NDT +34)C and for crack velocities in the range 200 ms -1 to 1000 ms -1 are presented. The connection between propagating crack toughness values and the rapidly loaded stationary crack toughness K/sub Id/ is examined

78 FR 41995 - Actions Taken Pursuant to Executive Order 13382

Science.gov (United States)

2013-07-12

...-hour fax-on-demand service, Tel.: 202/622-0077. Background On June 28, 2005, the President, invoking... Executive Order 13382. The list of additional designees is as follows: 1. DAEDONG CREDIT BANK (a.k.a. DAE-DONG CREDIT BANK; a.k.a. DCB; a.k.a. TAEDONG CREDIT BANK), Suite 401, Potonggang Hotel, Ansan-Dong...

Mechanism of electric fatigue crack growth in lead zirconate titanate

International Nuclear Information System (INIS)

Westram, Ilona; Oates, William S.; Lupascu, Doru C.; Roedel, Juergen; Lynch, Christopher S.

2007-01-01

A series of experiments was performed with through-thickness cracks in ferroelectric double cantilever beam (DCB) specimens. Cyclic electric fields of different amplitudes were applied which resulted in cyclic crack propagation perpendicular to the electric field direction. Crack propagation was observed optically and three regimes were identified: a pop-in from a notch, steady-state crack growth and a decrease of the crack growth rate with increasing cycle number. Crack growth only occurred if the applied field exceeded the coercive field strength of the material. Furthermore, the crack extended during each field reversal and the crack growth rate increased with increasing field. Based on the experimental observations, a mechanistic understanding was developed and contrasted with a nonlinear finite element analysis which quantified the stress intensity in the DCB specimens. The driving forces for crack formation at the notch and subsequent fatigue crack growth were computed based on the distribution of residual stresses due to ferroelectric switching. The finite element results are in good agreement with the experimental observations and support the proposed mechanism

Cadmium uptake by and translocation within rice (oryza sativa l.) seedlings as affected by iron plaque and Fe/sub 2/O/sub 3/

International Nuclear Information System (INIS)

Lai, Y.; Xu, B.O.; Mou, S.

2012-01-01

A hydroponics culture experiment was carried out to investigate the effect of iron plaque and/or Fe/sub 2/O/sub 3/ on Cadmium (Cd) uptake by and translocation within rice seedlings. Uniform rice seedlings grown in nutrient solution for two weeks were selected and transferred to nutrient solution containing ferrous iron (Fe/sup 2+/) (30 mg/L) for 24 h to induce the formation of iron plaque on the root surface. Then rice seedlings were exposed to different level of Cd (1.0 mg/L and 0.1 mg/L), and simultaneously Fe/sub 2/O/sub 3/ was added into hydroponic system for three days. At harvest Cd content in dithionite-citrate-bicarbonate (DCB) extracts, roots and shoots were determined. The results of this study showed that iron plaque could sequester more Cd on root surfaces of rice seedlings, however, Fe/sub 2/O/sub 3/ reduced Cd adsorbed on root surfaces. Both of iron plaque and/or Fe/sub 2/O/sub 3/ did not block Cd uptake by and translocation within rice seedlings. Although iron plaque could alleviate Cd toxicity to rice seedlings under low concentration of Cd (0.1 mg/L), the root tissue played more important role in reducing Cd translocation into shoot. And the long period experiment of hydroponic and soil culture was still needed to verify the potential effect of iron plaque and/or Fe/sub 2/O/sub 3/ on alleviating Cd toxicity to rice seedlings. (author)

Development of a Compton suppression whole body counting for small animals; Desenvolvimento de um detetor de corpo inteiro com supressao Compton para pequenos animais

Energy Technology Data Exchange (ETDEWEB)

Martini, Elaine

1996-12-31

The basic operation, design and construction of the plastic scintillator detector is described. In order to increase the sensitivity of this detector, two blocks of plastic scintillator have been assembled to act as a anticompton system. The detectors were produced by polymerisation of styrene monomer with PPO (2,5 diphenyl-oxazole) and POPOP (1,4 bis (-5 phenyl-2- oxazoly)benzene) in proportions of 0.5 and 0.05 respectively. The transparency of this detector was evaluated by excitation of the {sup 241} Am source located directly in the back surface plastic coupled to a photomultiplier. The light attenuation according to the detector thickness has fitted to a two-exponential function: relative height pulse = 0,519 e{sup -0.0016} + 0.481 e{sup -0.02112.x}. Four radioactive sources{sup {sup 2}2} Na, {sup 54} Mn, {sup 137} Cs and {sup 131} I were used to evaluate the performance of this system. The Compton reduction factor, determined by the ratio of the energy peak values of suppressed and unsuppressed spectra was 1.16. The Compton suppression factor determined by the ratio of the net photopeak area to the area of an equal spectra width in the Compton continuum, was approximately 1.208 {+-} 0.109. The sensitivity of the system, defined as the least amount of a radioactivity that can be quantified in the photopeak region, was 9.44 cps. First, the detector was assembled to be applied in biological studies of whole body counter measurements of small animals. Using a phantom, (small animal simulator) and a punctual {sup 137} Cs source, located in the central region of the well counter the geometrical efficiency detector was about 5%. (author) 40 refs., 28 fifs., 2 tabs.

Development of a Compton suppression whole body counting for small animals; Desenvolvimento de um detetor de corpo inteiro com supressao Compton para pequenos animais

Energy Technology Data Exchange (ETDEWEB)

Martini, Elaine

1995-12-31

The basic operation, design and construction of the plastic scintillator detector is described. In order to increase the sensitivity of this detector, two blocks of plastic scintillator have been assembled to act as a anticompton system. The detectors were produced by polymerisation of styrene monomer with PPO (2,5 diphenyl-oxazole) and POPOP (1,4 bis (-5 phenyl-2- oxazoly)benzene) in proportions of 0.5 and 0.05 respectively. The transparency of this detector was evaluated by excitation of the {sup 241} Am source located directly in the back surface plastic coupled to a photomultiplier. The light attenuation according to the detector thickness has fitted to a two-exponential function: relative height pulse = 0,519 e{sup -0.0016} + 0.481 e{sup -0.02112.x}. Four radioactive sources{sup {sup 2}2} Na, {sup 54} Mn, {sup 137} Cs and {sup 131} I were used to evaluate the performance of this system. The Compton reduction factor, determined by the ratio of the energy peak values of suppressed and unsuppressed spectra was 1.16. The Compton suppression factor determined by the ratio of the net photopeak area to the area of an equal spectra width in the Compton continuum, was approximately 1.208 {+-} 0.109. The sensitivity of the system, defined as the least amount of a radioactivity that can be quantified in the photopeak region, was 9.44 cps. First, the detector was assembled to be applied in biological studies of whole body counter measurements of small animals. Using a phantom, (small animal simulator) and a punctual {sup 137} Cs source, located in the central region of the well counter the geometrical efficiency detector was about 5%. (author) 40 refs., 28 fifs., 2 tabs.

The biosynthesis and wall-binding of hemicelluloses in cellulose-deficient maize cells: an example of metabolic plasticity.

Science.gov (United States)

de Castro, María; Miller, Janice G; Acebes, José Luis; Encina, Antonio; García-Angulo, Penélope; Fry, Stephen C

2015-04-01

Cell-suspension cultures (Zea mays L., Black Mexican sweet corn) habituated to 2,6-dichlorobenzonitrile (DCB) survive with reduced cellulose owing to hemicellulose network modification. We aimed to define the hemicellulose metabolism modifications in DCB-habituated maize cells showing a mild reduction in cellulose at different stages in the culture cycle. Using pulse-chase radiolabeling, we fed habituated and non-habituated cultures with [(3)H]arabinose, and traced the distribution of (3)H-pentose residues between xylans, xyloglucans and other polymers in several cellular compartments for 5 h. Habituated cells were slower taking up exogenous [(3)H]arabinose. Tritium was incorporated into polysaccharide-bound arabinose and xylose residues, but habituated cells diverted a higher proportion of their new [(3)H]xylose residues into (hetero) xylans at the expense of xyloglucan synthesis. During logarithmic growth, habituated cells showed slower vesicular trafficking of polymers, especially xylans. Moreover, habituated cells showed a decrease in the strong wall-binding of all pentose-containing polysaccharides studied; correspondingly, especially in log-phase cultures, habituation increased the proportion of (3)H-hemicelluloses ([(3)H]xylans and [(3)H]xyloglucan) sloughed into the medium. These findings could be related to the cell walls' cellulose-deficiency, and consequent reduction in binding sites for hemicelluloses; the data could also reflect the habituated cells' reduced capacity to integrate arabinoxylans by extra-protoplasmic phenolic cross-linking, as well as xyloglucans, during wall assembly. © 2015 Institute of Botany, Chinese Academy of Sciences.

Photoacidic and Photobasic Behavior of Transition Metal Compounds with Carboxylic Acid Group(s)

Energy Technology Data Exchange (ETDEWEB)

O’Donnell, Ryan M. [Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States; Sampaio, Renato N. [Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States; Li, Guocan [Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States; Johansson, Patrik G. [Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States; Ward, Cassandra L. [Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States; Meyer, Gerald J. [Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States

2016-03-10

Excited state proton transfer studies of six Ru polypyridyl compounds with carboxylic acid/carboxylate group(s) revealed that some were photoacids and some were photobases. The compounds [Ru^II(btfmb)₂(LL)]²⁺, [Ru^II(dtb)2(LL)]2+, and [RuII(bpy)2(LL)]2+, where bpy is 2,2'-bipyridine, btfmb is 4,4'-(CF₃)₂-bpy, and dtb is 4,4'-((CH₃)₃C)₂-bpy, and LL is either dcb = 4,4'-(CO₂H)₂-bpy or mcb = 4-(CO₂H),4'-(CO2Et)-2,2'-bpy, were synthesized and characterized. The compounds exhibited intense metal-to-ligand charge-transfer (MLCT) absorption bands in the visible region and room temperature photoluminescence (PL) with long τ > 100 ns excited state lifetimes. The mcb compounds had very similar ground state pKa’s of 2.31 ± 0.07, and their characterization enabled accurate determination of the two pK_a values for the commonly utilized dcb ligand, pK_a1 = 2.1 ± 0.1 and pKa2 = 3.0 ± 0.2. Compounds with the btfmb ligand were photoacidic, and the other compounds were photobasic. Transient absorption spectra indicated that btfmb compounds displayed a [Ru^III(btfmb–)L₂]^2+* localized excited state and a [Ru^III(dcb–)L₂]^2+* formulation for all the other excited states. Time dependent PL spectral shifts provided the first kinetic data for excited state proton transfer in a transition metal compound. PL titrations, thermochemical cycles, and kinetic analysis (for the mcb compounds) provided self-consistent pK_a* values. The ability to make a single ionizable group photobasic or photoacidic through ligand design was unprecedented and was understood based on the orientation of the lowest-lying MLCT excited state dipole relative to the ligand that contained the carboxylic acid group(s).

Critical experiments, measurements and analyses to establish a crack arrest methodology for nuclear pressure vessel steels. Sixth quarterly progress report, January--March 1976

International Nuclear Information System (INIS)

Hahn, G.T.; Gehlen, P.C.; Hoagland, R.G.; Kanninen, M.F.; Popelar, C.; Rosenfield, A.R.

1976-07-01

Governing equations for a complete two-dimensional analysis of fast fracture and crack arrest (including inertia and thermal gradients) are derived. Strain energy and compliance values calculated for an SEN specimen agree with experiment. In the case of a nonstationary crack, the strain energy release rate is computed from the nodal displacements in the immediate vicinity of the crack tip. This value of G is sensitive to the spacings between nodes in the x and y direction. Results of two-dimensional analyses of propagation and arrest in the SEN test piece are also described; they are in general accord with one propagation event measured in an SEN A533B steel test piece. Compliance measurements were carried out on the rectangular DCB specimen to test the accuracy of the compliance values calculated with the one-dimensional beam-on-elastic-foundation model. These compliance values and the derivatives of compliance with crack length are used to relate the loads or displacements at fracture onset and at arrest to K/sub Q/, K/sub D/, and K/sub a/. Efforts were also made to test the assumption that energy losses arising from damping remote from the crack tip can be neglected. Measurements of damped oscillations in an A533B DCB specimen with a stationary crack indicate that total damping rates are relatively low, and that oscillations of the load pins in the pinhole account for the bulk of the damping. Finally, a new procedure for measuring K/sub D/ and K/sub m/ values is described; it is based on a dynamic analysis of the crack length at arrest and dynamically stiff wedge loading (the tie-down device) and eliminates the need for crack velocity measurements. It can also be applied to both small and large crack jumps and to ordinary and duplex-DCB specimens. Results for A533B steel agree with K/sub D/-values obtained from velocity measurements. The new procedure is also used to analyze results for a series of ship steels

FUn: a framework for interactive visualizations of large, high-dimensional datasets on the web.

Science.gov (United States)

Probst, Daniel; Reymond, Jean-Louis

2018-04-15

During the past decade, big data have become a major tool in scientific endeavors. Although statistical methods and algorithms are well-suited for analyzing and summarizing enormous amounts of data, the results do not allow for a visual inspection of the entire data. Current scientific software, including R packages and Python libraries such as ggplot2, matplotlib and plot.ly, do not support interactive visualizations of datasets exceeding 100 000 data points on the web. Other solutions enable the web-based visualization of big data only through data reduction or statistical representations. However, recent hardware developments, especially advancements in graphical processing units, allow for the rendering of millions of data points on a wide range of consumer hardware such as laptops, tablets and mobile phones. Similar to the challenges and opportunities brought to virtually every scientific field by big data, both the visualization of and interaction with copious amounts of data are both demanding and hold great promise. Here we present FUn, a framework consisting of a client (Faerun) and server (Underdark) module, facilitating the creation of web-based, interactive 3D visualizations of large datasets, enabling record level visual inspection. We also introduce a reference implementation providing access to SureChEMBL, a database containing patent information on more than 17 million chemical compounds. The source code and the most recent builds of Faerun and Underdark, Lore.js and the data preprocessing toolchain used in the reference implementation, are available on the project website (http://doc.gdb.tools/fun/). daniel.probst@dcb.unibe.ch or jean-louis.reymond@dcb.unibe.ch.

Fracture Mechanics Analysis of Reinforced DCB Sandwich Debond Specimen Loaded by Moments

DEFF Research Database (Denmark)

Saseendran, Vishnu; Berggreen, Christian; Carlsson, Leif A.

2018-01-01

a pure moment loading is considered. The J-integral coupled with laminate beam theory is employed to derive closed-form expression for the energy releaserate in terms of the applied moments, geometry, and material properties .A scalar quantityωis obtained to express the mode-mixity phase angle...

Environmentally persistent free radicals inhibit cytochrome P450 activity in rat liver microsomes

Energy Technology Data Exchange (ETDEWEB)

Reed, James R., E-mail: rreed@lsuhsc.edu [Department of Pharmacology and Experimental Therapeutics, Louisiana State University Health Science Center, 533 Bolivar St., New Orleans, LA 70112 (United States); The Stanley S. Scott Cancer Center, Louisiana State University Health Science Center, 533 Bolivar St., New Orleans, LA 70112 (United States); Cawley, George F.; Ardoin, Taylor G. [Department of Pharmacology and Experimental Therapeutics, Louisiana State University Health Science Center, 533 Bolivar St., New Orleans, LA 70112 (United States); The Stanley S. Scott Cancer Center, Louisiana State University Health Science Center, 533 Bolivar St., New Orleans, LA 70112 (United States); Dellinger, Barry; Lomnicki, Slawomir M.; Hasan, Farhana; Kiruri, Lucy W. [Department of Chemistry, Louisiana State University, Baton Rouge, LA 70803 (United States); Backes, Wayne L. [Department of Pharmacology and Experimental Therapeutics, Louisiana State University Health Science Center, 533 Bolivar St., New Orleans, LA 70112 (United States); The Stanley S. Scott Cancer Center, Louisiana State University Health Science Center, 533 Bolivar St., New Orleans, LA 70112 (United States)

2014-06-01

Combustion processes generate particulate matter that affects human health. When incineration fuels include components that are highly enriched in aromatic hydrocarbons (especially halogenated varieties) and redox-active metals, ultrafine particulate matter containing air-stable, environmentally persistent free radicals (EPFRs) is generated. The exposure to fine EPFRs (less than 2.5 μm in diameter) has been shown to negatively influence pulmonary and cardiovascular functions in living organisms. The goal of this study was to determine if these EPFRs have a direct effect on cytochrome P450 function. This was accomplished by direct addition of the EPFRs to rat liver microsomal preparations and measurement of several P450 activities using form-selective substrates. The EPFRs used in this study were formed by heating vapors from an organic compound (either monochlorophenol (MCP230) or 1,2-dichlorobenzene (DCB230)) and 5% copper oxide supported on silica (approximately 0.2 μm in diameter) to 230 °C under vacuum. Both types of EPFRs (but not silica, physisorbed silica, or silica impregnated with copper oxide) dramatically inhibited the activities of CYP1A, CYP2B, CYP2E1, CYP2D2 and CYP3A when incubated at concentrations less than 0.1 mg/ml with microsomes and NADPH. Interestingly, at the same concentrations, the EPFRs did not inhibit HO-1 activity or the reduction of cytochrome c by NADPH-cytochrome P450 reductase. CYP2D2-selective metabolism by rat liver microsomes was examined in more detail. The inhibition of CYP2D2-selective metabolism by both DCB230- and MCP230-EPFRs appeared to be largely noncompetitive and was attenuated in the presence of catalase suggesting that reactive oxygen species may be involved in the mechanism of inhibition. - Highlights: • Combustion of organic pollutants generates long-lived particulate radicals (EPFRs). • EPFRs inhibit metabolism by all cytochromes P450 tested in rat liver microsomes. • EPFR-mediated inhibition is related to

Environmentally persistent free radicals inhibit cytochrome P450 activity in rat liver microsomes

International Nuclear Information System (INIS)

Reed, James R.; Cawley, George F.; Ardoin, Taylor G.; Dellinger, Barry; Lomnicki, Slawomir M.; Hasan, Farhana; Kiruri, Lucy W.; Backes, Wayne L.

2014-01-01

Combustion processes generate particulate matter that affects human health. When incineration fuels include components that are highly enriched in aromatic hydrocarbons (especially halogenated varieties) and redox-active metals, ultrafine particulate matter containing air-stable, environmentally persistent free radicals (EPFRs) is generated. The exposure to fine EPFRs (less than 2.5 μm in diameter) has been shown to negatively influence pulmonary and cardiovascular functions in living organisms. The goal of this study was to determine if these EPFRs have a direct effect on cytochrome P450 function. This was accomplished by direct addition of the EPFRs to rat liver microsomal preparations and measurement of several P450 activities using form-selective substrates. The EPFRs used in this study were formed by heating vapors from an organic compound (either monochlorophenol (MCP230) or 1,2-dichlorobenzene (DCB230)) and 5% copper oxide supported on silica (approximately 0.2 μm in diameter) to 230 °C under vacuum. Both types of EPFRs (but not silica, physisorbed silica, or silica impregnated with copper oxide) dramatically inhibited the activities of CYP1A, CYP2B, CYP2E1, CYP2D2 and CYP3A when incubated at concentrations less than 0.1 mg/ml with microsomes and NADPH. Interestingly, at the same concentrations, the EPFRs did not inhibit HO-1 activity or the reduction of cytochrome c by NADPH-cytochrome P450 reductase. CYP2D2-selective metabolism by rat liver microsomes was examined in more detail. The inhibition of CYP2D2-selective metabolism by both DCB230- and MCP230-EPFRs appeared to be largely noncompetitive and was attenuated in the presence of catalase suggesting that reactive oxygen species may be involved in the mechanism of inhibition. - Highlights: • Combustion of organic pollutants generates long-lived particulate radicals (EPFRs). • EPFRs inhibit metabolism by all cytochromes P450 tested in rat liver microsomes. • EPFR-mediated inhibition is related to

Compound-Specific Isotope Analysis (CSIA Application for Source Apportionment and Natural Attenuation Assessment of Chlorinated Benzenes

Directory of Open Access Journals (Sweden)

Luca Alberti

2017-11-01

Full Text Available In light of the complex management of chlorobenzene (CB contaminated sites, at which a hydraulic barrier (HB for plumes containment is emplaced, compound-specific stable isotope analysis (CSIA has been applied for source apportionment, for investigating the relation between the upgradient and downgradient of the HB, and to target potential CB biodegradation processes. The isotope signature of all the components potentially involved in the degradation processes has been expressed using the concentration-weighted average δ13C of CBs + benzene (δ13Csum. Upgradient of the HB, the average δ13Csum of −25.6‰ and −29.4‰ were measured for plumes within the eastern and western sectors, respectively. Similar values were observed for the potential sources, with δ13Csum values of −26.5‰ for contaminated soils and −29.8‰ for the processing water pipeline in the eastern and western sectors, respectively, allowing for apportioning of these potential sources to the respective contaminant plumes. For the downgradient of the HB, similar CB concentrations but enriched δ13Csum values between −24.5‰ and −25.9‰ were measured. Moreover, contaminated soils showed a similar δ13Csum signature of −24.5‰, thus suggesting that the plumes likely originate from past activities located in the downgradient of the HB. Within the industrial property, significant δ13C enrichments were measured for 1,2,4-trichlorobenzene (TCB, 1,2-dichlorobenzene (DCB, 1,3-DCB, and 1,4-DCBs, thus suggesting an important role for anaerobic biodegradation. Further degradation of monochlorobenzene (MCB and benzene was also demonstrated. CSIA was confirmed to be an effective approach for site characterization, revealing the proper functioning of the HB and demonstrating the important role of natural attenuation processes in reducing the contamination upgradient of the HB.

In situ synthesis of nanoparticles on substrates by inkjet printing

KAUST Repository

Abulikemu, Mutalifu; Jabbour, Ghassan

2014-01-01

Nanoparticles may be formed on a substrate by mixing precursor solutions deposited by an inkjet printer. A first solution is deposited on a substrate from a first inkjet print cartridge. Then, a second solution is deposited on the substrate from a second inkjet print cartridge. The solutions may be printed in an array of droplets on the substrate. Nanoparticles form when droplets of the first solution overlap with droplets of the second solution. In one example, the nanoparticles may be gold nanoparticles formed from mixing a first solution of 1,2-dichlorobenzene (DCB) and oleylamine and a second solution of gold chloride trihydrite and dimethyl sulfoxide (DMSO). The nanoparticles may be incorporated into optoelectronic devices.

In situ synthesis of nanoparticles on substrates by inkjet printing

KAUST Repository

Abulikemu, Mutalifu

2014-12-23

Nanoparticles may be formed on a substrate by mixing precursor solutions deposited by an inkjet printer. A first solution is deposited on a substrate from a first inkjet print cartridge. Then, a second solution is deposited on the substrate from a second inkjet print cartridge. The solutions may be printed in an array of droplets on the substrate. Nanoparticles form when droplets of the first solution overlap with droplets of the second solution. In one example, the nanoparticles may be gold nanoparticles formed from mixing a first solution of 1,2-dichlorobenzene (DCB) and oleylamine and a second solution of gold chloride trihydrite and dimethyl sulfoxide (DMSO). The nanoparticles may be incorporated into optoelectronic devices.

Proceedings of Damping 󈨡 Held in San Francisco, California on 24-26 February 1993. Volume 3.

Science.gov (United States)

1993-06-01

initial test of the new approach was carried out with the data obtained by testing a nitrile butadiene rubber ( NBR ). A novel technique, the Fourier...Figure 6 shows G’ versus frequency for NBR (nitrile butadiene rubber ) at various temperatures. The data was determined using FTMA apparatus [5,6]. Data...Temperature Behavior of DCB Polyisobutylene Dr. David I. G. Jones Estimation of Dynamic Properties of Rubber Materials and their DCC Applications to

Cellulose acetate fibers covered by CdS nanoparticles for hybrid solar cell applications

Energy Technology Data Exchange (ETDEWEB)

Cortina, Hugo; Martinez-Alonso, Claudia [Centro de Investigacion en Energia, UNAM, Priv. Xochicalco S/N, Temixco, Morelos 62580 (Mexico); Castillo-Ortega, Monica [Universidad de Sonora, Hermosillo, Sonora 83000 (Mexico); Hu, Hailin, E-mail: hzh@cie.unam.mx [Centro de Investigacion en Energia, UNAM, Priv. Xochicalco S/N, Temixco, Morelos 62580 (Mexico)

2012-09-20

In this work cellulose acetate (CA) fibers with a diameter of approximately 1 {mu}m were immersed in a cadmium sulfide (CdS) precursor solution. After 3 h the original white color CA fibers became yellow and maintained the same form, suggesting the deposition of CdS on fiber surface. SEM images showed that CA fibers were covered by uniformly sized CdS nanoparticles of approximately 100 nm. XRD and optical absorption spectra indicated that they contained mostly cubic crystalline phase with the optical band gap of 2.43 eV. CdS coated CA fibers, called CdS(CA) fibers, were dispersed in a polar dispersant (dimethyl sulfoxide, DMSO) and then mixed with a poly(3-hexylthiophene) (P3HT) solution in a non-polar solvent (dichlorobenzene, DCB). The mixture was cast onto a transparent conductive glass substrate (Indium-Tin-Oxide, ITO), and after solvent evaporation a thin layer of CdS(CA)-P3HT composite was formed. It is observed that the volume relation between the polar dispersant and non-polar solvent influences the solubility of the P3HT product in the composite coating and the photovoltaic performance of the corresponding cell as well. The mass ratio between CdS(CA) fibers and P3HT in the composite layer affects the optical absorption of the composite. The best photovoltaic performance was obtained in CdS(CA)-P3HT based cells with a volume relation between DCB and DMSO of 3.5-1, a mass ratio between CdS(CA) and P3HT of 1:1, and a rapid drying process for composite coatings.

Study of DDT and its derivatives DDD, DDE adsorption and degradation over Fe-SBA-15 at low temperature

Institute of Scientific and Technical Information of China (English)

Hailin Wang; Hua Tian; Zhengping Hao

2012-01-01

Mesoporous SBA-15 with different Fe2O3 loading were synthesized by an in-situ coating progress for removals of dichlorodiphenyltrichloroethane(DDT)and its derivatives,i.e.,1,1-dichloro-2,2-bis-(p-chlorophenyl)ethane(DDD)and 1,l-dichloro-2,2-bis-(4-chloro -phenyl)ethane(DDE).The results from XRD(X-ray diffractometer),TEM(transmission electron microscopy)indicated that the iron could be well dispersed on SBA-15 within 6 wt.% Fe2O3 loading.Nitrogen adsorption-desorption tests indicated that the synthesized materials were characterized by ordered meso-structure,high surface area and large pore volume.DDTs were removed from aqueous media in 12-hr treatment and high removal efficiency of DDTs was achieved at over 94%.DDTs could be completely degraded at 350℃ under the existence of SBA-15 with 4 wt.% Fe2O3 loading.The final degradation products of DDT were dichlorobenzophenone (DCB)and bis-(4-chloro-phenyl)methane(DDM),suggesting a complete dechlorination from trichloromethyl.

DISCRETIONARY COLLABORATIVE BEHAVIOUR (DCB) OF STUDENTS FROM INSTITUTES OF HIGHER LEARNING IN MALAYSIA

OpenAIRE

Huam Hon Tat; Muhamad Jantan; Mohd. Nasser Mohd. Noor

2008-01-01

It is generally accepted that a graduate who is satisfied with the quality of his or her educational experience is likely to reciprocate by performing certain behaviours that benefit the alma mater. Whether or not this reciprocating behaviour is consistent across all individuals, however, is much less clear. The present study addresses this question using the Satisfaction with Life Scale (SWLS) to measure life satisfaction. Three components of intended discretionary collaborative behaviours (...

DISCRETIONARY COLLABORATIVE BEHAVIOUR (DCB OF STUDENTS FROM INSTITUTES OF HIGHER LEARNING IN MALAYSIA

Directory of Open Access Journals (Sweden)

Huam Hon Tat

2008-01-01

Full Text Available It is generally accepted that a graduate who is satisfied with the quality of his or her educational experience is likely to reciprocate by performing certain behaviours that benefit the alma mater. Whether or not this reciprocating behaviour is consistent across all individuals, however, is much less clear. The present study addresses this question using the Satisfaction with Life Scale (SWLS to measure life satisfaction. Three components of intended discretionary collaborative behaviours (IDCB – institutional support, word-of-mouth, and financial contributions –were extracted from factor analysis. Using data from 167 usable responses to a mail and e-mail survey of 1,500 MBA graduates, we find that for low levels of life satisfaction, the impact of overall student satisfaction (OSS on the components of IDCB was either negligible or negative. However, for high levels of life satisfaction, the impact was generally in a positive direction, and a moderate level of OSS was already sufficient for the graduates to perform intended discretionary services in terms of word-of-mouth and financial contributions. Taken together, the outcomes of this study may offer preliminary support that, even though the occurrence of student dissatisfaction with overall services is known to reduce the likelihood of IDCBs, it is possible that high levels of life satisfaction may serve as support against the non-performance of IDCBs.

Mission Accomplishment through Outsourcing

Science.gov (United States)

2006-02-07

salary only and does not include associated benefits. According to the U.S. 7 Chamber of Commerce , employee benefit costs represent 37.6 percent of...articles/ glossary.html#o. 10 Office of Personnel Management, U.S. Government, http://www.opm.gov/oca/06tables/html/dcb.asp. 11 U.S. Chamber of Commerce , http...employee% 20turnover. U.S. Chamber of Commerce . http://www.uschamber.com/press/ releases/2005/january//05-13.htm. USGA. “Employee Turnover

Extração de ferro de esmectita brasileira com emprego do método ditionito-citrato-bicarbonato Iron extraction from Brazilian smectite by dithionite-citrate-bicarbonate method

Directory of Open Access Journals (Sweden)

Sidnei Quezada M. Leite

2000-06-01

Full Text Available A natural clay from Campina Grande region (Paraíba, Brazil, with 8.57% of Fe2O3, was used to study the most appropriate condition to carry out the iron extraction, without altering the clay structure in a significant way. Samples were treated with the Dithionite-Citrate-Bicarbonate method (DCB for 30 and 120 minutes (pH=9.1, and also with citric acid (pH=1.8; time=15min, at 75°C. Conductivity measurements, X-ray fluorescence, X-ray diffraction, energy-dispersive spectrometry, electron-diffraction with transmission electron microscopy and textural evaluation by nitrogen adsorption were done. The treatment in a basic medium was more selective for iron removal than in acid condition. The time of 30 minutes, with 1.6 g Na2S2O4/10 g clay, was the best condition for the iron extraction.

Influence of grain boundaries on the fracture toughness of tungsten alloys

International Nuclear Information System (INIS)

Gludovatz, B.; Faleschini, M.; Pippan, R.; Hoffmann, A.

2007-01-01

Full text of publication follows: Tungsten and tungsten alloys are possible candidates for future fusion reactors because of their high melting points, high thermal conductivity and their high erosion resistance. Since these materials have a body-centered cubic (bcc) structure, they show a typical change in fracture behaviour from brittle at low temperatures to ductile at high temperatures. For that reason the fracture behaviour of pure tungsten (W), potassium doped tungsten (AKS) and tungsten with 1 wt% La 2 O 3 (WL10) was studied, taking into account the influence of temperature and fabrication condition. Especially AKS has been studied to investigate the longitudinal splitting of the AKS-wires, the crack propagation direction with the lowest fracture toughness. This alloy subjected to intense deformation leads to a material with an elongated grain structure after recrystallization because of the potassium bubbles. Fracture toughness has been investigated by means of 3-point bending (3PB) specimens, double cantilever beam (DCB) specimens and compact tension (CT) specimens. Tests were performed in the range -196 deg. C to more than 1000 deg. C. Though all these materials show an expected increase in fracture toughness with increasing temperature, influences like texture, chemical composition, grain boundary segregation and dislocation density seem to have an extreme influence on the obtained results. These influences can especially be seen in the fracture behaviour and morphology, where two kinds of fracture can occur: on one hand the trans-crystalline and on the other hand the intercrystalline fracture. Therefore techniques like electron backscatter diffraction, auger electron spectroscopy and X-ray line profile analysis were used to determine the parameter influencing fracture toughness. Also new testing techniques have been devised and successfully applied. Additional tests like an 'in-situ EBSD' technique for investigating the formation of dislocations during

A comparative study on the uptake and translocation of organochlorines by Phragmites australis

Energy Technology Data Exchange (ETDEWEB)

San Miguel, Angélique; Ravanel, Patrick [Laboratoire d’Ecologie Alpine, UMR CNRS n°5553, Université Joseph Fourier, BP 53, 38041 Grenoble Cedex 09 (France); Raveton, Muriel, E-mail: muriel.raveton@ujf-grenoble.fr [Laboratoire d’Ecologie Alpine, UMR CNRS n°5553, Université Joseph Fourier, BP 53, 38041 Grenoble Cedex 09 (France)

2013-01-15

Highlights: ► This study compares uptake/translocation of organochlorine congeners in macrophytes. ► First, root OC uptake was strongly linked with the partitioning/diffusion process. ► With time exposure, bioconcentration increased with OC solubility and volatility. ► Translocation was linked to the combination of water flow and vapor flux transfers. ► The most volatile OCs might be phytovolatilized from foliar surfaces. -- Abstract: Organochlorines (OCs) are persistent chemicals found in various environmental compartments. The differences in the uptake of {sup 14}C-labeled 1,4-dichlorobenzene (DCB), 1,2,4-trichlorobenzene (TCB) and γ-hexachlorocyclohexane (γHCH) by Phragmites australis were investigated under hydroponic conditions. The first step in sorption appears to be correlated with the hydrophobic nature of the compounds, since log-linear correlations were obtained between root concentration factor and partition coefficient (LogK{sub ow}). After 7 days of exposure, plant uptake of DCB, TCB, γHCH was significant with bioconcentration factors reaching 14, 19 and 15, respectively. Afterwards, uptake and translocation were seen to be more complex, with a loss of the simple relationship between uptake and LogK{sub ow}. Linear correlations between the bioconcentration/translocation factors and the physico-chemical properties of OCs were shown, demonstrating that translocation from roots to shoots increases with solubility and volatility of the OCs. This suggests that OC-translocation inside plants might result from the combination of two processes, xylem sap flow and vapor fluxes. {sup 14}C-phytovolatilization was measured and was correlated with the volatility of the compounds; the more volatile OCs being most the likely to be phytovolatilized from foliar surfaces (p = 0.0008). Thus, OC-uptake/translocation appears to proceed at a rate that depends mostly on the OCs hydrophobicity, solubility and volatility.

A J Integral Approach for Measuring Cohesive Laws Using a Modified DCB Sandwich Specimen

DEFF Research Database (Denmark)

Lundsgaard-Larsen, Christian; Berggreen, Christian; Sørensen, Bent F.

2007-01-01

mode mixities. The sandwich specimen consists of glass fiber faces and Divinycell H200 foam core. Arbitrary stiffening of the sandwich specimen with steel bars adhered to the faces reduces rotations and ensures that the method is useable for a wide range of materials. The J integral is employed...... and the opening of the pre-crack tip is recorded by a commercial digital photogrammetry measurement system. Cohesive laws are extracted by differentiating J with respect to the normal and tangential opening of the pre-crack tip. Some results are presented and discussed....

Critical experiments, measurements, and analyses to establish a crack arrest methodology for nuclear pressure vessel steels

International Nuclear Information System (INIS)

Hahn, G.T.

1977-01-01

Substantial progress was made in three important areas: crack propagation and arrest theory, two-dimensional dynamic crack propagation analyses, and a laboratory test method for the material property data base. The major findings were as follows: Measurements of run-arrest events lent support to the dynamic, energy conservation theory of crack arrest. A two-dimensional, dynamic, finite-difference analysis, including inertia forces and thermal gradients, was developed. The analysis was successfully applied to run-arrest events in DCB (double-cantilever-beam) and SEN (single-edge notched) test pieces. A simplified procedure for measuring K/sub D/ and K/sub Im/ values with ordinary and duplex DCB specimens was demonstrated. The procedure employs a dynamic analysis of the crack length at arrest and requires no special instrumentation. The new method was applied to ''duplex'' specimens to measure the large K/sub D/ values displayed by A533B steel above the nil-ductility temperature. K/sub D/ crack velocity curves and K/sub Im/ values of two heats of A533B steel and the corresponding values for the plane strain fracture toughness associated with static initiation (K/sub Ic/), dynamic initiation (K/sub Id/), and the static stress intensity at crack arrest (K/sub Ia/) were measured. Possible relations among these toughness indices are identified. During the past year the principal investigators of the participating groups reached agreement on a crack arrest theory appropriate for the pressure vessel problem. 7 figures

Lipid drug conjugate nanoparticle as a novel lipid nanocarrier for the oral delivery of decitabine: ex vivo gut permeation studies

International Nuclear Information System (INIS)

Neupane, Yub Raj; Sabir, M D; Ahmad, Nafees; Ali, Mushir; Kohli, Kanchan

2013-01-01

The purpose of this study was to develop lipid drug conjugate (LDC) nanoparticles of decitabine (DCB) using stearic acid as a lipid to increase the permeability of the drug along with its protection from chemical degradation. The LDC was prepared by salt formation of DCB with stearic acid and followed by cold homogenization technique to produce the LDC nanoparticles. The role of key independent variables influencing on dependent variables were determined by using a Box–Behnken design. The optimized batch revealed spherical morphology under TEM analysis with particle size of 202.6 ± 1.65 nm and 0.334 ± 0.987 PDI. The zeta potential and %EE were found to be −33.6 ± 0.845 mV and 68.89% ± 0.59 respectively. Lyophilized powder showed the crystalline structure under DSC analysis. In vitro release studies showed the initial burst release followed by a sustained release up to 24 h in PBS pH 7.4 and the data were further studied using release kinetic models which revealed the first-order model as a best-fitting model. Ex vivo gut permeation studies proved that the formulation containing lipid and surfactants has a higher permeability than the plain drug solution with nearly fourfold increase in the apparent permeability coefficients. Finally, LDC nanoparticles prepared by using stearic acid as a lipid and surfactants as Tween 80, Poloxamer 188, and Labrasol in equal ratio possess high potential for the oral delivery of hydrophilic drugs. (paper)

Lipid drug conjugate nanoparticle as a novel lipid nanocarrier for the oral delivery of decitabine: ex vivo gut permeation studies

Science.gov (United States)

Neupane, Yub Raj; Sabir, M. D.; Ahmad, Nafees; Ali, Mushir; Kohli, Kanchan

2013-10-01

The purpose of this study was to develop lipid drug conjugate (LDC) nanoparticles of decitabine (DCB) using stearic acid as a lipid to increase the permeability of the drug along with its protection from chemical degradation. The LDC was prepared by salt formation of DCB with stearic acid and followed by cold homogenization technique to produce the LDC nanoparticles. The role of key independent variables influencing on dependent variables were determined by using a Box-Behnken design. The optimized batch revealed spherical morphology under TEM analysis with particle size of 202.6 ± 1.65 nm and 0.334 ± 0.987 PDI. The zeta potential and %EE were found to be -33.6 ± 0.845 mV and 68.89% ± 0.59 respectively. Lyophilized powder showed the crystalline structure under DSC analysis. In vitro release studies showed the initial burst release followed by a sustained release up to 24 h in PBS pH 7.4 and the data were further studied using release kinetic models which revealed the first-order model as a best-fitting model. Ex vivo gut permeation studies proved that the formulation containing lipid and surfactants has a higher permeability than the plain drug solution with nearly fourfold increase in the apparent permeability coefficients. Finally, LDC nanoparticles prepared by using stearic acid as a lipid and surfactants as Tween 80, Poloxamer 188, and Labrasol in equal ratio possess high potential for the oral delivery of hydrophilic drugs.

In Search of a Time Efficient Approach to Crack and Delamination Growth Predictions in Composites

Science.gov (United States)

Krueger, Ronald; Carvalho, Nelson

2016-01-01

Analysis benchmarking was used to assess the accuracy and time efficiency of algorithms suitable for automated delamination growth analysis. First, the Floating Node Method (FNM) was introduced and its combination with a simple exponential growth law (Paris Law) and Virtual Crack Closure technique (VCCT) was discussed. Implementation of the method into a user element (UEL) in Abaqus/Standard(Registered TradeMark) was also presented. For the assessment of growth prediction capabilities, an existing benchmark case based on the Double Cantilever Beam (DCB) specimen was briefly summarized. Additionally, the development of new benchmark cases based on the Mixed-Mode Bending (MMB) specimen to assess the growth prediction capabilities under mixed-mode I/II conditions was discussed in detail. A comparison was presented, in which the benchmark cases were used to assess the existing low-cycle fatigue analysis tool in Abaqus/Standard(Registered TradeMark) in comparison to the FNM-VCCT fatigue growth analysis implementation. The low-cycle fatigue analysis tool in Abaqus/Standard(Registered TradeMark) was able to yield results that were in good agreement with the DCB benchmark example. Results for the MMB benchmark cases, however, only captured the trend correctly. The user element (FNM-VCCT) always yielded results that were in excellent agreement with all benchmark cases, at a fraction of the analysis time. The ability to assess the implementation of two methods in one finite element code illustrated the value of establishing benchmark solutions.

Structural health monitoring method for wind turbine trailing edge: Crack growth detection using Fibre Bragg Grating sensor embedded in composite materials

DEFF Research Database (Denmark)

Pereira, Gilmar Ferreira; Mikkelsen, Lars Pilgaard; McGugan, Malcolm

2015-01-01

In this article a novel method to assess a crack growing/damage event in composite material using Fibre Bragg Grating (FBG) sensors embedded in a host material and its application into a composite material structure, Wind Turbine Trailing Edge, is presented. A Structure-Material-FBG model......, such as compression fields ahead the crack or non-uniform strain fields, and then identify the presence of such damage in the structure. Experimental tests were conducted to fully characterize this concept and support the model. Double Cantilever Beams (DCB), made with two glass fibre beams glued with structural...

Modelling the double cantilever beam test with bending moments by using bilinear discontinuous cohesive laws

DEFF Research Database (Denmark)

Valvo, Paolo S.; Sørensen, Bent F.; Toftegaard, Helmuth Langmaack

2015-01-01

A theoretical model of the double cantilever beam tests with bending moments (DCB-UBM) is presented. The specimen is modelled as the assemblage of two laminated beams connected by a cohesive interface. It is assumed that the traction-separation laws – i.e. the relationships between the interfacial...... the cohesive law parameters from experiments. Experimental tests have been conducted on glass fibre reinforced specimens under pure mode I and II loading conditions. The predictions of the theoretical model turn out to be in very good agreement with the experimental results....

Study on electrohydrodynamic jetting performance of organic solvents

Energy Technology Data Exchange (ETDEWEB)

Lee, Soo Hong; Nguyen, Xuan Hung; Gim, Yeong Hyeon; Ko, Han Seo [Sungkyunkwan University, Suwon (Korea, Republic of)

2015-11-15

The electrohydrodynamic (EHD) inkjet method is a printing technology using electricity. This technique allows for the printing of EML (Emission layer) materials, usually used for OLED devices, on a substrate. In this study, ejection experiments were performed with various solvents to verify which of them is properly ejected in the EHD method. The solvents employed were dielectric liquids with low viscosity and it was confirmed that among them two solvents, 1,2-Dichlorobenzene (DCB) and 1,2-Dichloroethane (DCE), produced the pulsating cone-Jet mode and stable cone-jet mode well. In addition, experiments were conducted to find out how the voltage and applied flux influence the ejection mode, in order to apply the result to the ejection control. It was found that the selected solvent was easily ejected and printed, due to the free surface charge and charge density determined by the dielectric constant. Finally, a patterning experiment was performed to verify proper printing.

Radiation degradation of aromatic pollutants exit in wastewater and ph dependence

CERN Document Server

Takriti, S

2002-01-01

The effect of gamma radiation on the degradation of phenol (hydroxybenzene), resorcinol (1,3 dihydroxybenzen) and hydroquinone (1,4 dihydroxybenzen) exit in waste water was investigated. The concentrations of these pollutants as well as the irradiated solution ph were studied. The results showed that the phenol is very resistance against the radiation doses comparing the other phenol compounds. Phenol was also a product of radiolysis of resorcinol and hydroquinone. On the other hand, the acid phase of the irradiation sample increased the degradation rate of pollutants. Spectrophotometer (UV-VIS) and chromatography (HPLC) were used to monitor the analysis of the radiation product solution. The results illustrated the existing of many substances such as organic alcohol, aldehyde, ketone and acidic functional groups as a final radiation products. The degradation of benzene, monochlorobenzene (CB) and 1,2 dichlorobenzene (1,2 DCB) exit in waste water by gamma irradiation was investigated. The effect of the irradi...

The relative stress-corrosion-cracking susceptibility of candidate aluminum-lithium alloys for aerospace applications

Science.gov (United States)

Pizzo, P. P.

1982-01-01

Stress corrosion tests of Al-Li-Cu powder metallurgy alloys are described. Alloys investigated were Al-2.6% Li-1.4% and Al-2.6% Li-1.4% Cu-1.6% Mg. The base properties of the alloys were characterized. Process, heat treatment, and size/orientational effects on the tensile and fracture behavior were investigated. Metallurgical and electrochemical conditions are identified which provide reproducible and controlled parameters for stress corrosion evaluation. Preliminary stress corrosion test results are reported. Both Al-Li-Cu alloys appear more susceptible to stress corrosion crack initiation than 7075-T6 aluminum, with the magnesium bearing alloy being the most susceptible. Tests to determine the threshold stress intensity for the base and magnesium bearing alloys are underway. Twelve each, bolt loaded DCB type specimens are under test (120 days) and limited crack growth in these precracked specimens has been observed. General corrosion in the aqueous sodium chloride environment is thought to be obscuring results through crack tip blunting.

Interface debonding characterization by image correlation integrated with Double Cantilever Beam kinematics

KAUST Repository

Blaysat, Benoît

2015-03-01

A procedure is proposed for the identification of spatial interfacial traction profiles of peel loaded Double Cantilever Beam (DCB) samples, from which the corresponding traction-separation relation is extracted. The procedure draws upon recent developments in the area of non-contact optical techniques and makes use of so-called Integrated Digital Image Correlation (I-DIC) concepts. The distinctive feature of the I-DIC approach proposed herein is that the unknown degrees of freedom are not displacements or rotations, but the set of interfacial fracture properties describing the traction profile. A closed-form theoretical model is developed to reconstruct a mechanically admissible displacement field representing the deformation of the adhering layers during debonding in the DCB fracture test. The proposed modeling accounts for the spatial traction profile along the interface between the adherends using few degrees of freedom, i.e. crack tip position, maximum stress and size of the process zone. By minimizing the correlation residual with respect to the degrees of freedom, the full set of interfacial fracture properties is obtained through a one-step algorithm, revealing a substantial gain in terms of computational efficiency and robustness. It is shown that the identified traction profile can be effectively combined with the crack opening displacement to extract the corresponding traction-separation relation, i.e. the key input data for any cohesive zone model (CZM). The proposed procedure is validated by post-processing virtually deformed images generated through the finite element method. The robustness with respect to noisy data, as well as the low sensitivity to the initial guess, are demonstrated.

Study on crack propagation of adhesively bonded DCB for aluminum foam using energy release rate

Energy Technology Data Exchange (ETDEWEB)

Bang, Hye Jin; Lee, Sang Kyo; Cho, Chong Du [Inha University, Incheon (Korea, Republic of); Cho, Jae Ung [Kongju National University, Choenan (Korea, Republic of)

2015-01-15

Aluminum foam with initial crack, which has a closed cell form adhesively bonded, is studied to compare and analyze the crack propagation behavior by using both experimental and finite element analysis techniques. The specimen is loaded in Mode I type of fracture as 15 mm/min speed of a displacement control method. The experimental results were used to accommodate the finite element analysis performed with commercial software ABAQUS 6.10. First, using a video recording, five steps of experiment were selected at random and then the energy release rate was calculated. The estimated energy release rate was then used as fracture energy into the finite element analysis. Comparing the experimental axial load-displacement graphs and the finite element analysis results, roughly equivalent peak values were observed in the cohesive strength of the aluminum foam double cantilever beam. However, force versus displacement patterns showed somewhat different: little deformation was observed in aluminum foam, whereas adhesive parts in double cantilever beam were significantly deformed.

Identification of parameters of cohesive elements for modeling of adhesively bonded joints of epoxy composites

Directory of Open Access Journals (Sweden)

Kottner R.

2013-12-01

Full Text Available Adhesively bonded joints can be numerically simulated using the cohesive crack model. The critical strain energy release rate and the critical opening displacement are the parameters which must be known when cohesive elements in MSC.Marc software are used. In this work, the parameters of two industrial adhesives Hunstman Araldite 2021 and Gurit Spabond 345 for bonding of epoxy composites are identified. Double Cantilever Beam (DCB and End Notched Flexure (ENF test data were used for the identification. The critical opening displacements were identified using an optimization algorithm where the tests and their numerical simulations were compared.

Determination of a cohesive law for delamination modelling - Accounting for variation in crack opening and stress state across the test specimen width

DEFF Research Database (Denmark)

Joki, R. K.; Grytten, F.; Hayman, Brian

2016-01-01

by differentiating the fracture resistance with respect to opening displacement at the initial location of the crack tip, measured at the specimen edge. 2) Extend the bridging law to a cohesive law by accounting for crack tip fracture energy. 3) Fine-tune the cohesive law through an iterative modelling approach so......The cohesive law for Mode I delamination in glass fibre Non-Crimped Fabric reinforced vinylester is determined for use in finite element models. The cohesive law is derived from a delamination test based on DCB specimens loaded with pure bending moments taking into account the presence of large...... that the changing state of stress and deformation across the width of the test specimen is taken into account. The changing state of stress and deformation across the specimen width is shown to be significant for small openings (small fracture process zone size). This will also be important for the initial part...

Using the Climbing Drum Peel (CDP) Test to Obtain a G(sub IC) value for Core/Facesheet Bonds

Science.gov (United States)

Nettles, A. T.; Gregory, Elizabeth D.; Jackson, Justin R.

2006-01-01

A method of measuring the Mode I fracture toughness of core/facesheet bonds in sandwich Structures is desired, particularly with the widespread use of models that need this data as input. This study examined if a critical strain energy release rate, G(sub IC), can be obtained from the climbing drum peel (CDP) test. The CDP test is relatively simple to perform and does not rely on measuring small crack lengths such as required by the double cantilever beam (DCB) test. Simple energy methods were used to calculate G(sub IC) from CDP test data on composite facesheets bonded to a honeycomb core. Facesheet thicknesses from 2 to 5 plies were tested to examine the upper and lower bounds on facesheet thickness requirements. Results from the study suggest that the CDP test, with certain provisions, can be used to find the GIG value of a core/facesheet bond.

TOPOGRAFÍA INTRANEURAL DE LA RAMA PROFUNDA DEL NERVIO ULNAR EN EL ANTEBRAZO DISTAL: ESTUDIO CADAVÉRICO. Intraneural topography of the deep branch of the ulnar nerve in the distal forearm: cadaveric study.

Directory of Open Access Journals (Sweden)

Joaquín García Pisón

2016-07-01

the deep branch of the ulnar nerve was performed under magnification (Olympus OME, 4-20x and its intraneural position was registered using a quadrants scheme. Distance from pisiform to the origin of the dorsal cutaneous branch of the ulnar nerve (DCB was measured and its intraneural position relative to DBUN was identified. Results: The DBUN could be identified up to 69mm (41-94 proximal to the pisiform and occupied the posteromedial quadrant of the ulnar nerve in 78% (67-87, 93% (92-93 and 100% of the cases in the 0-2, 3-6 and 7-9cm ranges, respectively. Distance from pisiform to the origin of the DCB was 63mm (52-83. The DBUN could be identified proximal to the origin of the DCB in 11 forearms, being located between the latter and the superficial branch of the ulnar nerve in all this cases.  Conclusions: Intraneural topography of the DBUN in the most appropriate site for its identification during its anastomosis to the PQN is predictable in the majority of cases, which supports the viability of safe identification of the de DBUN by means of minimal intraneural dissection.

Atributos químicos, mineralógicos e micromorfológicos de horizontes coesos de latossolos e argissolos dos tabuleiros costeiros do estado de Alagoas Mineralogy and micromorphology of cohesive horizons in oxisols and ultisols of the coastal tablelands of Alagoas, Brazil

Directory of Open Access Journals (Sweden)

José de Almeida Lima Neto

2010-04-01

Full Text Available O caráter coeso é um atributo característico de horizontes subsuperficiais que, quando secos, apresentam consistência muito dura e extremamente dura, passando a friável ou firme quando úmidos. A formação desses horizontes, entretanto, ainda é um assunto polêmico, não estando completamente esclarecida. O objetivo deste trabalho foi realizar uma caracterização química, mineralógica e micromorfológica de solos coesos, visando entender a sua gênese e definir características que possam complementar a definição do caráter coeso no Sistema Brasileiro de Classificação de Solos. Quatro perfis de solos foram coletados na região dos tabuleiros costeiros de Alagoas, envolvendo um Argissolo Amarelo, um Argissolo Acinzentado e dois Latossolos Amarelos. Os solos foram descritos morfologicamente, e as amostras dos horizontes coesos e não coesos foram coletadas para execução de análises químicas de Fe, Al e Si por extração com DCB, oxalato, CaCl2 e água quente, análises mineralógicas por DRX e caracterização micromorfológica. Os solos apresentaram baixos teores de Fe, com domínio das formas de baixa cristalinidade e predominância de caulinitas com moderado a alto grau de desordem estrutural em todos os horizontes. Não foi observada, nos horizontes coesos, tendência de aumento dos teores de Al e Si extraídos com DCB e oxalato, indicando que a sua gênese não se deve à presença de agentes cimentantes. Os resultados das análises mineralógicas e micromorfológicas sugerem que a gênese do caráter coeso apresenta duas fases distintas, sendo formado inicialmente pelo entupimento dos poros decorrente da iluviação de argila fina, havendo posteriormente uma perda de Fe na parte superior, que colapsa a estrutura e provoca um ajuste face a face da caulinita.The cohesive character is a property of subsurface soil horizons with hard to extremely hard consistency when dry, and friable or firm when wet. Despite the agricultural

Removal of selected pollutants from aqueous media by hardwood mulch

International Nuclear Information System (INIS)

Ray, Asim B.; Selvakumar, Ariamalar; Tafuri, Anthony N.

2006-01-01

Generic hardwood mulch, usually used for landscaping, was utilized to remove several selected pollutants (heavy metals and toxic organic compounds) typically found in urban stormwater (SW) runoff. The hardwood mulch sorbed all the selected pollutants from a spiked stormwater mixture, including copper (Cu 2+ ), cadmium (Cd 2+ ), chromium (Cr 6+ ), lead (Pb 2+ ), zinc (Zn 2+ ), 1,3 dichlorobenzene (DCB), naphthalene (NP), fluoranthene (FA), butylbenzylphthalate (BBP), and benzo(a)pyrene (B[a]P). Masses of the pollutants sorbed depended upon the pollutant species, contact time, and initial concentration which varied from 20 to 100%. Sorption rates of the metals, in general, were more rapid than those of the organics; however, mass removals (percent) of the organics, in contrast to those of the metals, were independent of their initial concentrations. With the exception of Cd, percentages (weight) of the metals removed declined as their initial concentrations decreased. None of the sorbed pollutants desorbed to any significant extent upon extended washing with water. It is quite feasible that in the presence of mulch the uptake of these pollutants by the aquatic species will be reduced significantly

Cadmium availability in rice paddy fields from a mining area: The effects of soil properties highlighting iron fractions and pH value.

Science.gov (United States)

Yu, Huan-Yun; Liu, Chuanping; Zhu, Jishu; Li, Fangbai; Deng, Dong-Mei; Wang, Qi; Liu, Chengshuai

2016-02-01

Cadmium (Cd) availability can be significantly affected by soil properties. The effect of pH value on Cd availability has been confirmed. Paddy soils in South China generally contain high contents of iron (Fe). Thus, it is hypothesized that Fe fractions, in addition to pH value, may play an important role in the Cd bioavailability in paddy soil and this requires further investigation. In this study, 73 paired soil and rice plant samples were collected from paddy fields those were contaminated by acid mine drainage containing Cd. The contents of Fe in the amorphous and DCB-extractable Fe oxides were significantly and negatively correlated with the Cd content in rice grain or straw (excluding DCB-extractable Fe vs Cd in straw). In addition, the concentration of HCl-extractable Fe(II) derived from Fe(III) reduction was positively correlated with the Cd content in rice grain or straw. These results suggest that soil Fe redox could affect the availability of Cd in rice plant. Contribution assessment of soil properties to Cd accumulation in rice grain based on random forest (RF) and stochastic gradient boosting (SGB) showed that pH value should be the most important factor and the content of Fe in the amorphous Fe oxides should be the second most important factor in affecting Cd content in rice grain. Overall, compared with the studies from temperate regions, such as Europe and northern China, Fe oxide exhibited its unique role in the bioavailability of Cd in the reddish paddy soil from our study area. The exploration of practical remediation strategies for Cd from the perspective of Fe oxide may be promising. Copyright © 2015 Elsevier Ltd. All rights reserved.

Cancer risk disparities between hispanic and non-hispanic white populations: the role of exposure to indoor air pollution.

Science.gov (United States)

Hun, Diana E; Siegel, Jeffrey A; Morandi, Maria T; Stock, Thomas H; Corsi, Richard L

2009-12-01

Hispanics are the fastest growing minority group in the United States; however, minimal information is available on their cancer risks from exposures to hazardous air pollutants (HAPs) and how these risks compare to risks to non-Hispanic whites. We estimated the personal exposure and cancer risk of Hispanic and white adults who participated in the Relationships of Indoor, Outdoor, and Personal Air (RIOPA) study. We evaluated 12 of the sampled volatile organic compounds and carbonyls and identified the HAPs of most concern and their possible sources. Furthermore, we examined sociodemographic factors and building characteristics. Cumulative cancer risks (CCRs) estimated for Hispanics (median = 519 x 10(-6), 90th percentile = 3,968 x 10(-6)) and for whites (median = 443 x 10(-6), 90th percentile = 751 x 10(-6)) were much greater than the U.S. Environmental Protection Agency (EPA) benchmark of 10(-6). Cumulative risks were dominated by formaldehyde and p-dichlorobenzene (p-DCB) and, to a lesser extent, by acetaldehyde, chloroform, and benzene. Exposure to all of these compounds except benzene was primarily due to indoor residential sources. Hispanics had statistically higher CCRs than did whites (p DCB, chloroform, and benzene. Formaldehyde was the largest contributor to CCR for 69% of Hispanics and 88% of whites. Cancer risks for pollutants emitted indoors increased in houses with lower ventilation rates. Hispanics appear to be disproportionately affected by certain HAPs from indoor and outdoor sources. Policies that aim to reduce risk from exposure to HAPs for the entire population and population subgroups should consider indoor air pollution.

Modeling of fracture and durability of paste-bonded composite joints subjected to hygro-thermal-mechanical loading

Science.gov (United States)

Harris, David Lee

The objective of the research is to characterize the behavior of composite/composite joints with paste adhesive using both experimental testing and analytical modeling. In comparison with the conventional tape adhesive, joining composites using paste adhesive provides several advantages. The carbon fiber laminate material systems employed in this study included IM7 carbon fibers and 977-3 epoxy matrix assembled in prepreg tape, and AS4 carbon fibers and 977-3 epoxy matrix as a five-harness satin weave. The adhesive employed was EA 9394 epoxy. All laminates and test specimens were fabricated and inspected by Boeing using their standard propriety procedures. Three types of test specimens were used in the program. They were bonded double-lap shear (DLS), bonded double cantilever beam (DCB) and bonded interlaminar tension (ILT) specimens. A group of specimens were conditioned at elevated temperature and humidity in an environmental chamber at Boeing's facility and their moisture absorption recorded with time. Specimens were tested at room temperature dry and elevated temperatures. DCB and DLS specimens were tested in fatigue as well as static conditions. Two-dimensional finite element models of the three configurations were developed for determining stresses and strains using the ABAQUS finite element package code. Due to symmetry, only the one-half of the specimen needed to be considered thus reducing computational time. The effect of the test fixture is not taken into account instead equivalent distributed stresses are applied directly on the composite laminates. For each of the specimen, the distribution of Mises stress and the first strain invariant J1 are obtained to identify potential failure locations within a specimen.

A Mixed-Mode (I-II) Fracture Criterion for AS4/8552 Carbon/Epoxy Composite Laminate

Science.gov (United States)

Karnati, Sidharth Reddy

A majority of aerospace structures are subjected to bending and stretching loads that introduce peel and shear stresses between the plies of a composite laminate. These two stress components cause a combination of mode I and II fracture modes in the matrix layer of the composite laminate. The most common failure mode in laminated composites is delamination that affects the structural integrity of composite structures. Damage tolerant designs of structures require two types of materials data: mixed-mode (I-II) delamination fracture toughness that predicts failure and delamination growth rate that predicts the life of the structural component. This research focuses determining mixed-mode (I-II) fracture toughness under a combination of mode I and mode II stress states and then a fracture criterion for AS4/8552 composite laminate, which is widely used in general aviation. The AS4/8552 prepreg was supplied by Hexcel Corporation and autoclave fabricated into a 20-ply unidirectional laminate with an artificial delamination by a Fluorinated Ethylene Propylene (FEP) film at the mid-plane. Standard split beam specimens were prepared and tested in double cantilever beam (DCB) and end notched flexure modes to determine mode I (GIC) and II (GIIC) fracture toughnesses, respectively. The DCB specimens were also tested in a modified mixed-mode bending apparatus at GIIm /GT ratios of 0.18, 0.37, 0.57 and 0.78, where GT is total and GIIm is the mode II component of energy release rates. The measured fracture toughness, GC, was found to follow the locus a power law equation. The equation was validated for the present and literature experimental data.

Gas chromatographic/mass spectrometric and microbiological analyses on irradiated chicken

Science.gov (United States)

Parlato, A.; Calderaro, E.; Bartolotta, A.; D'Oca, M. C.; Giuffrida, S. A.; Brai, M.; Tranchina, L.; Agozzino, P.; Avellone, G.; Ferrugia, M.; Di Noto, A. M.; Caracappa, S.

2007-08-01

Ionizing radiation is widely used as treatment technique for food preservation. It involves among others reduction of microbial contamination, disinfestations, sprout inhibition and extension of shelf life of food. However, the commercialization of irradiated food requires the availability of reliable methods to identify irradiated foodstuffs. In this paper, we present results on the application to irradiated chicken of this method, based on the detection, in muscle and skin samples, of the peaks of ions 98 Da and 112 Da, in a ratio approximately 4:1, typical of radiation induced 2-dodecylcyclobutanones (2-DCB). Aim of the work was also to study the time stability of the measured parameters in samples irradiated at 3 and 5 kGy, and to verify the efficacy of the treatment from a microbiological point of view. Our results show that, one month after irradiation at 3 kGy, the method is suitable using the skin but not the muscle, while the measured parameters are detectable in both samples irradiated at 5 kGy. The microbial population was substantially reduced even at 3 kGy.

Gas chromatographic/mass spectrometric and microbiological analyses on irradiated chicken

Energy Technology Data Exchange (ETDEWEB)

Parlato, A. [Dipartimento di Ingegneria Nucleare, Universita di Palermo, Viale delle Scienze, Edificio 6, 90100 Palermo (Italy); Calderaro, E. [Dipartimento di Ingegneria Nucleare, Universita di Palermo, Viale delle Scienze, Edificio 6, 90100 Palermo (Italy); Bartolotta, A. [Dipartimento Farmacochimico, Tossicologico e Biologico, Universita di Palermo, via Archirafi 32, 90123 Palermo (Italy)]. E-mail: antonio.bartolotta@unipa.it; D' Oca, M.C. [Dipartimento Farmacochimico, Tossicologico e Biologico, Universita di Palermo, via Archirafi 32, 90123 Palermo (Italy); Giuffrida, S.A. [Dipartimento Farmacochimico, Tossicologico e Biologico, Universita di Palermo, via Archirafi 32, 90123 Palermo (Italy); Brai, M. [Dipartimento di Fisica e Tecnologie Relative, Universita di Palermo, Viale delle Scienze, Edificio 18, 90100 Palermo (Italy); Tranchina, L. [Dipartimento di Fisica e Tecnologie Relative, Universita di Palermo, Viale delle Scienze, Edificio 18, 90100 Palermo (Italy); Agozzino, P. [Dipartimento di Chimica e Tecnologie Farmaceutiche, Universita di Palermo, via Archirafi 32, 90123 Palermo (Italy); Avellone, G. [Dipartimento di Chimica e Tecnologie Farmaceutiche, Universita di Palermo, via Archirafi 32, 90123 Palermo (Italy); Ferrugia, M. [Dipartimento di Chimica e Tecnologie Farmaceutiche, Universita di Palermo, via Archirafi 32, 90123 Palermo (Italy); Di Noto, A.M. [Istituto Zooprofilattico Sperimentale della Sicilia ' A.Mirri' , Palermo (Italy); Caracappa, S. [Istituto Zooprofilattico Sperimentale della Sicilia ' A.Mirri' , Palermo (Italy)

2007-08-15

Ionizing radiation is widely used as treatment technique for food preservation. It involves among others reduction of microbial contamination, disinfestations, sprout inhibition and extension of shelf life of food. However, the commercialization of irradiated food requires the availability of reliable methods to identify irradiated foodstuffs. In this paper, we present results on the application to irradiated chicken of this method, based on the detection, in muscle and skin samples, of the peaks of ions 98 Da and 112 Da, in a ratio approximately 4:1, typical of radiation induced 2-dodecylcyclobutanones (2-DCB). Aim of the work was also to study the time stability of the measured parameters in samples irradiated at 3 and 5 kGy, and to verify the efficacy of the treatment from a microbiological point of view. Our results show that, one month after irradiation at 3 kGy, the method is suitable using the skin but not the muscle, while the measured parameters are detectable in both samples irradiated at 5 kGy. The microbial population was substantially reduced even at 3 kGy.

Gas chromatographic/mass spectrometric and microbiological analyses on irradiated chicken

International Nuclear Information System (INIS)

Parlato, A.; Calderaro, E.; Bartolotta, A.; D'Oca, M.C.; Giuffrida, S.A.; Brai, M.; Tranchina, L.; Agozzino, P.; Avellone, G.; Ferrugia, M.; Di Noto, A.M.; Caracappa, S.

2007-01-01

Ionizing radiation is widely used as treatment technique for food preservation. It involves among others reduction of microbial contamination, disinfestations, sprout inhibition and extension of shelf life of food. However, the commercialization of irradiated food requires the availability of reliable methods to identify irradiated foodstuffs. In this paper, we present results on the application to irradiated chicken of this method, based on the detection, in muscle and skin samples, of the peaks of ions 98 Da and 112 Da, in a ratio approximately 4:1, typical of radiation induced 2-dodecylcyclobutanones (2-DCB). Aim of the work was also to study the time stability of the measured parameters in samples irradiated at 3 and 5 kGy, and to verify the efficacy of the treatment from a microbiological point of view. Our results show that, one month after irradiation at 3 kGy, the method is suitable using the skin but not the muscle, while the measured parameters are detectable in both samples irradiated at 5 kGy. The microbial population was substantially reduced even at 3 kGy

New methodology to investigate potential contaminant mass fluxes at the stream-aquifer interface by combining integral pumping tests and streambed temperatures

International Nuclear Information System (INIS)

Kalbus, E.; Schmidt, C.; Bayer-Raich, M.; Leschik, S.; Reinstorf, F.; Balcke, G.U.; Schirmer, M.

2007-01-01

The spatial pattern and magnitude of mass fluxes at the stream-aquifer interface have important implications for the fate and transport of contaminants in river basins. Integral pumping tests were performed to quantify average concentrations of chlorinated benzenes in an unconfined aquifer partially penetrated by a stream. Four pumping wells were operated simultaneously for a time period of 5 days and sampled for contaminant concentrations. Streambed temperatures were mapped at multiple depths along a 60 m long stream reach to identify the spatial patterns of groundwater discharge and to quantify water fluxes at the stream-aquifer interface. The combined interpretation of the results showed average potential contaminant mass fluxes from the aquifer to the stream of 272 μg m -2 d -1 MCB and 71 μg m -2 d -1 DCB, respectively. This methodology combines a large-scale assessment of aquifer contamination with a high-resolution survey of groundwater discharge zones to estimate contaminant mass fluxes between aquifer and stream. - We provide a new methodology to quantify the potential contaminant mass flux from an aquifer to a stream

Modified cellulose synthase gene from Arabidopsis thaliana confers herbicide resistance to plants

Science.gov (United States)

Somerville, Chris R [Portola Valley, CA; Scheible, Wolf [Golm, DE

2007-07-10

Cellulose synthase ("CS"), a key enzyme in the biosynthesis of cellulose in plants is inhibited by herbicides comprising thiazolidinones such as 5-tert-butyl-carbamoyloxy-3-(3-trifluromethyl)phenyl-4-thiazolidinone (TZ), isoxaben and 2,6-dichlorobenzonitrile (DCB). Two mutant genes encoding isoxaben and TZ-resistant cellulose synthase have been isolated from isoxaben and TZ-resistant Arabidopsis thaliana mutants. When compared with the gene coding for isoxaben or TZ-sensitive cellulose synthase, one of the resistant CS genes contains a point mutation, wherein glycine residue 998 is replaced by an aspartic acid. The other resistant mutation is due to a threonine to isoleucine change at amino acid residue 942. The mutant CS gene can be used to impart herbicide resistance to a plant; thereby permitting the utilization of the herbicide as a single application at a concentration which ensures the complete or substantially complete killing of weeds, while leaving the transgenic crop plant essentially undamaged.

Adsorptive removal of hydrophobic organic compounds by carbonaceous adsorbents: a comparative study of waste-polymer-based, coal-based activated carbon, and carbon nanotubes.

Science.gov (United States)

Lian, Fei; Chang, Chun; Du, Yang; Zhu, Lingyan; Xing, Baoshan; Liu, Chang

2012-01-01

Adsorption of the hydrophobic organic compounds (HOCs) trichloroethylene (TCE), 1,3-dichlorobenzene (DCB), 1,3-dinitrobenzene (DNB) and gamma-hexachlorocyclohexane (HCH) on five different carbonaceous materials was compared. The adsorbents included three polymer-based activated carbons, one coal-based activated carbon (F400) and multiwalled carbon nanotubes (MWNT). The polymer-based activated carbons were prepared using KOH activation from waste polymers: polyvinyl chloride (PVC), polyethyleneterephthalate (PET) and tire rubber (TR). Compared with F400 and MWNT, activated carbons derived from PVC and PET exhibited fast adsorption kinetics and high adsorption capacity toward the HOCs, attributed to their extremely large hydrophobic surface area (2700 m2/g) and highly mesoporous structures. Adsorption of small-sized TCE was stronger on the tire-rubber-based carbon and F400 resulting from the pore-filling effect. In contrast, due to the molecular sieving effect, their adsorption on HCH was lower. MWNT exhibited the lowest adsorption capacity toward HOCs because of its low surface area and characteristic of aggregating in aqueous solution.

Modified cellulose synthase gene from 'Arabidopsis thaliana' confers herbicide resistance to plants

Energy Technology Data Exchange (ETDEWEB)

Somerville, Chris R.; Scieble, Wolf

2000-10-11

Cellulose synthase ('CS'), a key enzyme in the biosynthesis of cellulose in plants is inhibited by herbicides comprising thiazolidinones such as 5-tert-butyl-carbamoyloxy-3-(3-trifluromethyl) phenyl-4-thiazolidinone (TZ), isoxaben and 2,6-dichlorobenzonitrile (DCB). Two mutant genes encoding isoxaben and TZ-resistant cellulose synthase have been isolated from isoxaben and TZ-resistant Arabidopsis thaliana mutants. When compared with the gene coding for isoxaben or TZ-sensitive cellulose synthase, one of the resistant CS genes contains a point mutation, wherein glycine residue 998 is replaced by an aspartic acid. The other resistant mutation is due to a threonine to isoleucine change at amino acid residue 942. The mutant CS gene can be used to impart herbicide resistance to a plant; thereby permitting the utilization of the herbicide as a single application at a concentration which ensures the complete or substantially complete killing of weeds, while leaving the transgenic crop plant essentially undamaged.

Adsorptive removal of hydrophobic organic compounds by carbonaceous adsorbents: A comparative study of waste-polymer-based,coal-based activated carbon, and carbon nanotubes

Institute of Scientific and Technical Information of China (English)

Fei Lian; Chun Chang; Yang Du; Lingyan Zhu; Baoshan Xing; Chang Liu

2012-01-01

Adsorption of the hydrophobic organic compounds (HOCs) trichloroethylene (TCE),1,3-dichlorobenzene (DCB),1,3-dinitrobenzene (DNB) and γ-hexachlorocyclohexane (HCH) on five different carbonaceous materials was compared.The adsorbents included three polymer-based activated carbons,one coal-based activated carbon (F400) and multiwalled carbon nanotubes (MWNT).The polymerbased activated carbons were prepared using KOH activation from waste polymers:polyvinyl chloride (PVC),polyethyleneterephthalate (PET) and tire rubber (TR).Compared with F400 and MWNT,activated carbons derived from PVC and PET exhibited fast adsorption kinetics and high adsorption capacity toward the HOCs,attributed to their extremely large hydrophobic surface area (2700 m2/g) and highly mesoporous structures.Adsorption of small-sized TCE was stronger on the tire-rubber-based carbon and F400 resulting from the pore-filling effect.In contrast,due to the molecular sieving effect,their adsorption on HCH was lower.MWNT exhibited the lowest adsorption capacity toward HOCs because of its low surface area and characteristic of aggregating in aqueous solution.

A general mixed mode fracture mechanics test specimen: The DCB-specimen loaded with uneven bending moments

Energy Technology Data Exchange (ETDEWEB)

Soerensen, B.F.; Joergensen, K.; Oestergaard, R.C. [Risoe National Lab., Materials Dept., Roskilde (Denmark); Jacobsen, T.K. [LM Glasfiber A/S, Lunderskov (Denmark)

2004-03-01

A mixed mode specimen is proposed for fracture mechanics characterisation of adhesive joints, laminates and multilayers. The specimen is a double cantilever beam specimen loaded with uneven bending moments at the two free beams. By varying the ratio between the two applied moments, the full mode mixity range from pure mode I to pure mode II can be generated for the same specimen geometry. The specimen allows stable crack growth. In case of large scale crack bridging, mixed mode cohesive laws can be obtained by a J integral based approach. As a preliminary example, fracture of adhesive joints between two glass-fibre laminates was studied. The mixed mode fracture resistance increased with increasing crack length due to fibre cross over bridging, eventually reaching a steady-state level (R-curve behaviour). The steady-state fracture toughness level increased with increasing tangential crack opening displacement. Cohesive stresses were determined by a J integral approach. The deducted shear stress was found to be relative high ({approx} = 20 MPa) in comparison with the normal stress ({approx} = 1 MPa). (au)

A general mixed mode fracture mechanics test specimen: The DCB-specimen loaded with uneven bending moments

DEFF Research Database (Denmark)

Sørensen, Bent F.; Jørgensen, K.; Jacobsen, T.K.

2004-01-01

A mixed mode specimen is proposed for fracture mechanics characterisation of adhesive joints, laminates and multilayers. The specimen is a double cantilever beam specimen loaded with uneven bending moments at the two free beams. By varying the ratiobetween the two applied moments, the full mode...... glass-fibre laminates was studied. The mixed mode fracture resistance increased with increasing crack length due to fibre bridging, eventually reaching asteady-state level (R-curve behaviour). The steady-state fracture toughness level increased with increasing tangential crack opening displacement....

Relation between interlaminar fracture toughness and pressure condition in autoclave molding process of GFRP composite laminates; GFRP sekisoban no autoclave seikei ni okeru atsuryoku joken to sokan hakai jinseichi tono kankei

Energy Technology Data Exchange (ETDEWEB)

Jiang, J. [Osaka City University, Osaka (Japan); Motogi, S.; Fukuda, T. [Osaka City University, Osaka (Japan). Faculty of Engineering

1998-06-15

Relation between fracture toughness and pressure condition in autoclave molding of GF composite laminates is investigated. Glass/epoxy prepregs are molded under different curing pressures, and UD laminates of [O{sub 8}]T and [O{sub 16}]T are fabricated. The results of the double cantilever beam (DCB) test show that the curing pressure has certain influences on the interlaminar fracture toughness via the change in morphology of matrix resin and fibers between laminae, and via the change in interfacial strength of fiber and matrix. It is also found that the fiber/matrix interfacial strength increases as the curing pressure increases by SEM photographs of the fracture surface in GF UD laminates. 13 refs., 12 figs.

Shear Pressed Aligned Carbon Nanotubes and their use as Composite and Adhesive Interlayers

Science.gov (United States)

Stahl, James Joseph, III

The following studies utilize shearing force to consolidate and re-orient multi-walled carbon nanotubes (MWCNT) into a shear pressed sheet (SPS) preform. Carbon nanotube (CNT) array growth and shear pressing angle are studied to improve the quality of SPSs. Heat assisted vacuum infusion is used to form a nano-composite from the SPS preform, and mechanical properties are characterized and compared between non-functionalized and functionalized nano-composite tensile specimens. A novel functionalization technique is applied which rinses SPSs with an acidic wet chemical oxidation treatment of H2SO4 and KMnO4 in order to add sidewall carboxyl groups to the CNTs. This is shown to impart hydrophilicity to the SPS and improves composite modulus by 62%, strain-to-failure 42% and failure stress 113%. Composite laminates and joints are vulnerable to shearing forces which cause delamination in the former and failure in the latter. Damage is initiated and propagated at defects and free edges often due to high peel stress, which is much higher than the shear stress and functions as a tensile opening of the joint just as in Mode I delamination failure of laminate composites. In order to resist failure it is necessary to improve the strain-to-failure of the interphase where a crack propagates without sacrificing strength or modulus of the material, thus toughening the material without impacting the rigidity of the composite. Due to the similarity between peel stress/strain and Mode I delamination, the initiation fracture toughness of a double cantilever beam (DCB) test should provide a good indication of peel toughness at a joint free edge. Many studies have explored the possibility of improving Mode I fracture toughness (G IC) of a composite through locally incorporating a tough material into the interlaminar interphase; this material is termed an interleaf. Common interleaf categories are toughened adhesive, disperse particle, disperse fiber, short fiber nonwoven, and continuous

Investigations of mode I crack propagation in fibre-reinforced plastics with real time X-ray tests and simultaneous sound emission analysis

International Nuclear Information System (INIS)

Brunner, A.; Nordstrom, R.; Flueeler, P.

1992-01-01

The described investigation of crack formation and crack propagation in mode I (tensile stress) in fibre-reinforced plastic samples, especially uni-directional carbon fibre reinforced polyether-ether ketone (PEEK) has several aims. On the one hand, the phenomena of crack formation and crack propagation in these materials are to be studied, and on the other hand, the draft standards for these tests are to be checked. It was found that the combination of real time X-ray tests and simultaneous sound emission analysis is excellently suited for the basic examination of crack formation and crack propagation in DCB samples. With the aid of picture processing and analysis of the video representation, consistent crack lengths and resulting G IC values can be determined. (orig./RHM) [de

Effects of Forming Process on Composite mode I Interlaminar Fracture Toughness

Directory of Open Access Journals (Sweden)

CHEN Xingyi

2016-10-01

Full Text Available In order to compare and analyse the effect of two different kinds of forming process on composite mode I interlaminar fracture toughness, the DCB specimens were tested by using hypothesis inspeetion method.A finite element model was also used to simulate the crack propagation process.The results demonstrate that the average of mode I interlaminar fracture toughness from silicon rubber flexible mold forming is a bit higher than that from metal rigid mold forming.Howevers the variance of mode I interlaminar fracture toughness from the two groups shows no significant difference.The crack propagation process of the two forming process is similar. The established finite element model, which is identical to the test results, can predict the process of the crack expansion effectively.

Effect of Processing Conditions on Fracture Resistance and Cohesive Laws of Binderfree All-Cellulose Composites

DEFF Research Database (Denmark)

Goutianos, Stergios; Arévalo, R.; Sørensen, Bent F.

2014-01-01

molecules during the drying process. Defibrilation of the raw cellulose material is done in wet medium in a paper-like process. Panels with different refining time were tested and it was found than an increase in fibre fibrillation results in a lower fracture resistance. © 2014 Springer Science......The fracture properties of all-cellulose composites without matrix were studied using Double Cantilever Beam (DCB) sandwich specimens loaded with pure monotonically increasing bending moments, which give stable crack growth. The experiments were conducted in an environmental scanning electron...... microscope to a) perform accurate measurements of both the fracture energy for crack initiation and the fracture resistance and b) observe the microscale failure mechanisms especially in the the wake of the crack tip. Since the mechanical behaviour of the all-cellulose composites was non-linear, a general...

Structure of the first representative of Pfam family PF04016 (DUF364) reveals enolase and Rossmann-like folds that combine to form a unique active site with a possible role in heavy-metal chelation

International Nuclear Information System (INIS)

Miller, Mitchell D.; Aravind, L.; Bakolitsa, Constantina; Rife, Christopher L.; Carlton, Dennis; Abdubek, Polat; Astakhova, Tamara; Axelrod, Herbert L.; Chiu, Hsiu-Ju; Clayton, Thomas; Deller, Marc C.; Duan, Lian; Feuerhelm, Julie; Grant, Joanna C.; Han, Gye Won; Jaroszewski, Lukasz; Jin, Kevin K.; Klock, Heath E.; Knuth, Mark W.; Kozbial, Piotr; Krishna, S. Sri; Kumar, Abhinav; Marciano, David; McMullan, Daniel; Morse, Andrew T.; Nigoghossian, Edward; Okach, Linda; Reyes, Ron; Bedem, Henry van den; Weekes, Dana; Xu, Qingping; Hodgson, Keith O.; Wooley, John; Elsliger, Marc-André; Deacon, Ashley M.; Godzik, Adam; Lesley, Scott A.; Wilson, Ian A.

2010-01-01

The crystal structure of the first representative of DUF364 family reveals a combination of enolase N-terminal-like and C-terminal Rossmann-like folds. Analysis of the interdomain cleft combined with sequence and genome context conservation among homologs, suggests a unique catalytic site likely involved in the synthesis of a flavin or pterin derivative. The crystal structure of Dhaf4260 from Desulfitobacterium hafniense DCB-2 was determined by single-wavelength anomalous diffraction (SAD) to a resolution of 2.01 Å using the semi-automated high-throughput pipeline of the Joint Center for Structural Genomics (JCSG) as part of the NIGMS Protein Structure Initiative (PSI). This protein structure is the first representative of the PF04016 (DUF364) Pfam family and reveals a novel combination of two well known domains (an enolase N-terminal-like fold followed by a Rossmann-like domain). Structural and bioinformatic analyses reveal partial similarities to Rossmann-like methyltransferases, with residues from the enolase-like fold combining to form a unique active site that is likely to be involved in the condensation or hydrolysis of molecules implicated in the synthesis of flavins, pterins or other siderophores. The genome context of Dhaf4260 and homologs additionally supports a role in heavy-metal chelation

Bakery products from irradiated and non-irradiated eggs - analytical problems associated with the detection of irradiation in processed foods

International Nuclear Information System (INIS)

Grabowski, H.U. von; Pfordt, J.

1993-01-01

In spring and early summer 1992, a number of irradiated egg products were illegally imported into Germay. To prove the irradiation of these egg products, mainly combined gas chromatography-mass spectrometry was applied. With this present study we wanted to answer the question if we were also able to detect the use of irradiated eggs in processed foods. The processed food we chose to produce and to investigate was a tart layer. For this product, dilution effects are of minor importance as no extra fat was added. Thus, the layers' fat almost exclusively came from the eggs. To study the influence of emulsifiers, we produced batters both with and without adding an emulsifer. The unsaturted hydrocarbons C14:1, C16:3, C16:2, C17:2, and C17:1 served as markers for an irradiation. In the non-irradiated egg samples and in the tart layers produced from them, these compounds could not be detected (or in some cases only in small amounts). They were, however, detectable in all irradiated samples. DCB could be found in all irradiated egg samples and in the tart layers that were baked from irradiated eggs. It was not present in non-irradiated eggs and in tart layers produced from them. (orig./Vhe)

Red soil as a regenerable sorbent for high temperature removal of hydrogen sulfide from coal gas

International Nuclear Information System (INIS)

Ko, T.-H.; Chu Hsin; Lin, H.-P.; Peng, C.-Y.

2006-01-01

In this study, hydrogen sulfide (H 2 S) was removed from coal gas by red soil under high temperature in a fixed-bed reactor. Red soil powders were collected from the northern, center and southern of Taiwan. They were characterized by XRPD, porosity analysis and DCB chemical analysis. Results show that the greater sulfur content of LP red soils is attributed to the higher free iron oxides and suitable sulfidation temperature is around 773 K. High temperature has a negative effect for use red soil as a desulfurization sorbent due to thermodynamic limitation in a reduction atmosphere. During 10 cycles of regeneration, after the first cycle the red soil remained stable with a breakthrough time between 31 and 36 min. Hydrogen adversely affects sulfidation reaction, whereas CO exhibits a positive effect due to a water-shift reaction. COS was formed during the sulfidation stage and this was attributed to the reaction of H 2 S and CO. Results of XRPD indicated that, hematite is the dominant active species in fresh red soil and iron sulfide (FeS) is a product of the reaction between hematite and hydrogen sulfide in red soils. The spinel phase FeAl 2 O 4 was found during regeneration, moreover, the amount of free iron oxides decreased after regeneration indicating the some of the free iron oxide formed a spinel phase, further reducting the overall desulfurization efficiency

Comparative study of fast T 2-weighted images using respiratory triggered, breath-hold, fat suppression and phased array multi coil for liver evaluation by magnetic resonance imaging; Estudo comparativo das sequencias rapidas ponderadas em T2, utilizando-se sincronizacao respiratoria, apneia, supressao de gordura, bobina de corpo e bobina de sinergia para a avaliacao do figado pela ressonancia magnetica

Energy Technology Data Exchange (ETDEWEB)

Abbehusen, Cristiane L.; D' Ippolito, Giuseppe; Palacio, Glaucia A.S.; Szejnfeld, Jacob [Universidade Federal de Sao Paulo (UNIFESP), SP (Brazil). Escola Paulista de Medicina (EPM). Dept. de Diagnostico por Imagem]. E-mail: cabbehusen@hotmail.com

2003-10-01

The objective of this study was to compare both qualitatively and quantitatively six T 2-weighted turbo spin-echo sequences varying the respiratory compensation technique, associating or not fat tissue suppression and using different types of coils. We performed a prospective study of 71 consecutive patients that were submitted to MRI of the liver using a 1.5 T magnet. The six following pulse sequences were used: fat-suppressed respiratory triggered with conventional body coil; breath-hold fat-suppressed with conventional body coil; non-suppressed respiratory triggered with conventional body coil; breath-hold non fat-suppressed with conventional body coil; fat-suppressed respiratory triggered with phased-array multi coil; breath-hold fat-suppressed with phased-array multi coil. Images were analyzed quantitatively by measuring the signal-to-noise ratios and qualitatively by evaluating the sharpness of hepatic contours, visibility of intrahepatic vessels and other segmental landmarks, and the presence of artifacts. Results: the qualitative analysis showed that the mean values obtained with the six sequences were 7.8, 4.6, 7.9, 5.2, 6.7 and 4.6 respectively. The respiratory-triggered sequences were better than the breath-hold sequences in both qualitative and quantitative analysis (p < 0.001). No significant differences in the values of signal-to-noise ratios and in overall image quality were found between the sequences with and without fat suppression (p . 0.05). The sequences using the body coil were similar in terms of image quality (p . 0.05) and better regarding signal-to-noise ratios than those obtained with the phased=array multi coil (p ,0.001). Our qualitative and quantitative results suggest that the best MRI sequences for the valuation of the liver are the sequences with respiratory triggering using a conventional body coil, with or without fat suppression. (author)

Simulação na validação de sistemas computacionais para a agricultura de precisão Simulation in the validation of precision farming computing systems

Directory of Open Access Journals (Sweden)

Braulio A. de Mello

2008-12-01

Full Text Available Sistemas computacionais têm tido aplicação crescente na construção de sistemas para o setor agrícola; contudo, o trabalho de projeto desse tipo de sistemas tem-se tornado mais complexo devido à necessidade de se estabelecer cooperação entre componentes que não possuem uma interface comum e/ou construídos com tecnologias diferentes (heterogêneos; deste modo, os componentes são, geralmente, validados em separado e a observação do funcionamento do sistema completo ocorre somente nos testes com o uso de protótipos, retardando a identificação de problemas e gerando custos em tempo e recursos. O uso da simulação pode contribuir com a antecipação de experiências que permitam observar o comportamento da cooperação entre os componentes do sistema, com o objetivo de reduzir o tempo e o custo geral do projeto. Através de um sistema eletrônico de supervisão de plantio (SEP como estudo de caso, o artigo apresenta o uso do DCB (Distributed Cosimulation Backbone como ferramenta de modelagem e simulação de sistemas voltados para a agricultura de precisão para reduzir tempo e custos de projeto.Computing systems have been employed for agricultural purposes, mainly in the precision farming domain. However, their implementation is complex because the cooperation among system components formed by agricultural equipment and computing parts do not have a common interface and the components are developed over distinct technologies (heterogeneous components. Also, the components are individually validated and the cooperation among them can be observed only in experiments using prototypes, delaying the identification of errors and increasing general costs. Simulation techniques are used to observe the work of all systems using models. This paper discusses a heterogeneous simulation to improve the implementation process of precision agricultural systems that bind heterogeneous components. This article presents a solution based on DCB

Performance Evaluation and Durability Studies of Adhesive Bonds

Science.gov (United States)

Ranade, Shantanu Rajendra

In this thesis, four test approaches were developed to characterize the adhesion performance and durability of adhesive bonds for specific applications in areas spanning from structural adhesive joints to popular confectionaries such as chewing gum. In the first chapter, a double cantilever beam (DCB) specimen geometry is proposed for combinatorial fracture studies of structural adhesive bonds. This specimen geometry enabled the characterization of fracture energy vs. bondline thickness trends through fewer tests than those required during a conventional "one at a time" characterization approach, potentially offering a significant reduction in characterization times. The second chapter investigates the adhesive fracture resistance and crack path selection in adhesive joints containing patterns of discreet localized weak interfaces created using physical vapor deposition of copper. In a DCB specimen tested under mode-I conditions, fracture energy within the patterned regions scaled according to a simple rule of mixture, while reverse R-curve and R-curve type trends were observed in the regions surrounding weak interface patterns. Under mixed mode conditions such that bonding surface with patterns is subjected to axial tension, fracture energy did not show R-curve type trends while it was observed that a crack could be made to avoid exceptionally weak interfaces when loaded such that bonding surface with defects is subjected to axial compression. In the third chapter, an adaptation of the probe tack test is proposed to characterize the adhesion behavior of gum cuds. This test method allowed the introduction of substrates with well-defined surface energies and topologies to study their effects on gum cud adhesion. This approach and reported insights could potentially be useful in developing chewing gum formulations that facilitate easy removal of improperly discarded gum cuds from adhering surfaces. In the fourth chapter we highlight a procedure to obtain insights

The highly enhanced visible light photocatalytic degradation of gaseous o-dichlorobenzene through fabricating like-flowers BiPO{sub 4}/BiOBr p-n heterojunction composites

Energy Technology Data Exchange (ETDEWEB)

Zou, Xuejun [Department of Environmental Science and Technology, Dalian Nationalities University, Dalian, 116600 (China); Dong, Yuying, E-mail: dongy@dlnu.edu.cn [Department of Environmental Science and Technology, Dalian Nationalities University, Dalian, 116600 (China); Zhang, Xiaodong, E-mail: fatzhxd@126.com [Environment and Low-Carbon Research Center, School of Environment and Architecture, University of Shanghai for Science and Technology, Shanghai, 200093 (China); Cui, Yubo; Ou, Xiaoxia [Department of Environmental Science and Technology, Dalian Nationalities University, Dalian, 116600 (China); Qi, Xiaohui [College of Life Science, Dalian Nationalities University, Dalian, 116600 (China)

2017-01-01

Highlights: • Like-flowers BiPO{sub 4}/BiOBr was fabricated by mixing in solvent method. • o-Dichlorobenzene removal efficiency was 53.6% using BiPO{sub 4}/BiOBr. • The p–n junction improved o-dichlorobenzene degradation activity. - Abstract: In this paper, in order to enhance photo-induced electron-hole pairs separation of BiOBr, flowers-like BiPO{sub 4}/BiOBr p-n heterojunction composites was fabricated by a mixing in solvent method. The as-prepared samples were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM), UV–vis absorption spectroscopy (DRS), X-ray photoelectron spectroscopy (XPS), and N{sub 2} adsorption-desorption. Meanwhile, their photocatalytic properties were investigated by the degradation of gaseous o-dichlorobenzene under visible light irradiation. Due to its strong adsorption capacity and the formation of p-n heterojunction, compared with BiPO{sub 4} and BiOBr, the BiPO{sub 4}/BiOBr composites showed higher photocatalytic activity in the degradation of gaseous o-DCB under visible light. Among them, 2% BiPO{sub 4}/BiOBr showed the maximum value of the activity, whose degradation rate was about 2.6 times as great as the pure BiOBr. Furthermore, the OH· was confirmed the main active species during the photocatalytic process by the trapping experiments. The outstanding performance indicated that the photocatalysts could be applied to air purification for chlorinated volatile organic compound.

Quantitative Evaluation of Delamination in Composites Using Lamb Waves

Science.gov (United States)

Michalcová, L.; Hron, R.

2018-03-01

Ultrasonic guided wave monitoring has become very popular in the area of structural health monitoring (SHM) of aerospace structures. Any possible type of damage must be reliably assessed. The paper deals with delamination length determination in DCB specimens using Lamb waves. An analytical equation based on the velocity dependence on variable thickness is utilized. The group velocity of the fundamental antisymmetric A0 mode rapidly changes in a particular range of the frequency-thickness product. Using the same actuation frequency the propagation velocity is different for delaminated structure. Lamb wave based delamination lengths were compared to the visually determined lengths. The method of the wave velocity determination proved to be essential. More accurate results were achieved by tracking the maximum amplitude of A0 mode than the first signal arrival. These findings are considered as the basis for the damage evaluation of complex structures.

Effect of quenching and tempering process on sulfide stress cracking susceptibility in API-5CT-C110 casing steel

Energy Technology Data Exchange (ETDEWEB)

Liu, M.; Wang, C.H.; Dai, Y.C.; Li, X.; Cao, G.H. [State Key Laboratory of Advanced Special Steel & Shanghai Key Laboratory of Advanced Ferrometallurgy & School of Materials Science and Engineering, Shanghai University, 149 Yanchang Road, Shanghai 200072 (China); Russell, A.M. [Division of Materials Science and Engineering, Ames Laboratory of the U.S.D.O.E., and Department of Materials Science and Engineering, Iowa State University, Ames, IA 50011-2300 (United States); Liu, Y.H.; Dong, X.M. [Tube & Pipe Department, Baosteel Research Institute, Baoshan Iron & Steel Co., Ltd, Shanghai 201900 (China); Zhang, Z.H., E-mail: zhzhang@baosteel.com [Tube & Pipe Department, Baosteel Research Institute, Baoshan Iron & Steel Co., Ltd, Shanghai 201900 (China)

2017-03-14

Three quenching and tempering processes performed on API-5CT-C110 casing steel produced tempered martensite structures and similar mechanical properties but distinct sulfide stress cracking (SSC) behavior as evaluated by Double Cantilever Beam (DCB) testing. An as-quenched specimen tempered at 690 °C for two hours showed superior SSC behavior compared to another specimen tempered at 715 °C for one hour. The latter contained a larger fraction of low-angle boundaries (LABs) and higher values of kernel average misorientation (KAM) than those in the former. Moreover, one more quenching and tempering on the former specimen would produce better SSC resistance with a decrease in the fraction of LABs and the values of KAM. Since dislocations trap hydrogen more strongly than grain boundaries, the specimen with higher KAM values, as well as higher dislocation density, would trap more hydrogen atoms and lead to greater SSC.

Fracture property of double cantilever beam of aluminum foam bonded with spray adhesive

International Nuclear Information System (INIS)

Han, Moon Sik; Choi, Hae Kyu; Cho, Jae Ung; Cho, Chong Du

2015-01-01

Aluminum foam with the property of excellent impact absorption has been widely used recently. It is necessary to study fracture energy due to energy release rate by the use of adhesive joint at aluminum foam. This study aims at strength evaluation about adhesive joint on aluminum foam. Bonded DCB specimens with this material property are experimented and the fracture behavior is analyzed by simulation. These specimens are designed by differing in height on the basis of British industrial and ISO standards. As the value of height at model is higher, bonded part is separated to the end. By comparing analysis results with experimental data, these data could agree with each other. By the confirmation with experimental results, these all simulation results in this study can be applied on real composite structure with aluminum foam material effectively. The fracture behavior and its property can also be examined by this study.

A Unified Model for BDS Wide Area and Local Area Augmentation Positioning Based on Raw Observations

Directory of Open Access Journals (Sweden)

Rui Tu

2017-03-01

Full Text Available In this study, a unified model for BeiDou Navigation Satellite System (BDS wide area and local area augmentation positioning based on raw observations has been proposed. Applying this model, both the Real-Time Kinematic (RTK and Precise Point Positioning (PPP service can be realized by performing different corrections at the user end. This algorithm was assessed and validated with the BDS data collected at four regional stations from Day of Year (DOY 080 to 083 of 2016. When the users are located within the local reference network, the fast and high precision RTK service can be achieved using the regional observation corrections, revealing a convergence time of about several seconds and a precision of about 2–3 cm. For the users out of the regional reference network, the global broadcast State-Space Represented (SSR corrections can be utilized to realize the global PPP service which shows a convergence time of about 25 min for achieving an accuracy of 10 cm. With this unified model, it can not only integrate the Network RTK (NRTK and PPP into a seamless positioning service, but also recover the ionosphere Vertical Total Electronic Content (VTEC and Differential Code Bias (DCB values that are useful for the ionosphere monitoring and modeling.

Growth and galvanic replacement of silver nanocubes in organic media

Science.gov (United States)

Polavarapu, Lakshminarayana; Liz-Marzán, Luis M.

2013-05-01

Although metal nanoparticles with various shapes can be prepared in polar organic solvents, little has been advanced toward the shape-controlled synthesis in non-polar solvents. We report a simple method for the synthesis of nearly monodisperse single crystalline silver nanocubes in a non-polar solvent (1,2-dichlorobenzene) by using oleylamine as both a reducing and capping agent. Mechanistic studies based on the time evolution of Ag nanoparticles revealed that multiply twinned nanocrystals form at the beginning of the reaction, which are gradually transformed into single crystalline Ag nanocubes by oxidative etching. Control experiments showed that the solvent plays an important role in the formation of such single crystalline Ag nanocubes. The effects of reaction temperature, oleylamine concentration, solvent, and the nature of the silver ion precursor on the morphology and monodispersity of the nanoparticles were systematically investigated. Additionally, the galvanic replacement reaction with HAuCl4 in an organic medium was implemented to prepare hydrophobic hollow Au-Ag nanocages with tunable localized surface plasmon resonances.Although metal nanoparticles with various shapes can be prepared in polar organic solvents, little has been advanced toward the shape-controlled synthesis in non-polar solvents. We report a simple method for the synthesis of nearly monodisperse single crystalline silver nanocubes in a non-polar solvent (1,2-dichlorobenzene) by using oleylamine as both a reducing and capping agent. Mechanistic studies based on the time evolution of Ag nanoparticles revealed that multiply twinned nanocrystals form at the beginning of the reaction, which are gradually transformed into single crystalline Ag nanocubes by oxidative etching. Control experiments showed that the solvent plays an important role in the formation of such single crystalline Ag nanocubes. The effects of reaction temperature, oleylamine concentration, solvent, and the nature of the

Determining mode I cohesive law of Pinus pinaster by coupling double cantilever beam test with digital image correlation

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J. Xavier

2015-01-01

Full Text Available The direct identification of the cohesive law in pure mode I of Pinus pinaster is addressed. The approach couples the double cantilever beam (DCB test with digital image correlation (DIC. Wooden beam specimens loaded in the radial-longitudinal (RL fracture propagation system are used. The strain energy release rate in mode I ( is uniquely determined from the load-displacement ( curve by means of the compliance-based beam method (CBBM. This method relies on the concept of equivalent elastic crack length ( and therefore does not require the monitoring of crack propagation during test. The crack tip opening displacement in mode I is determined from the displacement field at the initial crack tip. The cohesive law in mode I is then identified by numerical differentiation of the relationship. Moreover, the proposed procedure is validated by finite element analyses including cohesive zone modelling. It is concluded that the proposed data reduction scheme is adequate for assessing the cohesive law in pure mode I of P. pinaster

Experimental Study On Fracture Property Of Double Cantilever Beam Specimen With Aluminum Foam

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Kim Y.C.

2015-06-01

Full Text Available This study aims to investigate double cantilever beam specimen with aluminum foam bonded by spray adhesive to investigate the fracture strength of the adhesive joint experimentally. The fracture energy at opening mode is calculated by the formulae of British Engineering Standard (BS 7991 and International Standard (ISO 11343. For the static experiment, four types of specimens with the heights (h of 25 mm, 30 mm, 35 mm and 40 mm are manufactured and the experimental results are compared with each other. As the height becomes greater, the fracture energy becomes higher. After the length of crack reaches 150 mm, the fracture energy of the specimen (h=35 mm is greater than that of the specimen (h=40 mm. Fatigue test is also performed with DCB test specimen. As the height decreases, the fracture energy becomes higher. By the result obtained from this study, aluminum foam with adhesive joint can be applied to actual composite structure and its fracture property can possibly be anticipated.

PCBs determination in water, soils and biota by perchlorination and GC-ECD

Energy Technology Data Exchange (ETDEWEB)

Feshin, D. [Institute of Ecology and Evolution RAS, Moscow (Russian Federation); Klyuev, N.; Brodsky, E.; Kalinkevich, G.

2004-09-15

Most of the PCB pollutions are caused by industrial application. PCB-containing mixtures whose compositions are well known and constant should be rapidly and precisely analyzable as total PCB to monitor real pollution exposure. Consequently, a simple but reproducible and cheap method for operative control is needed which should be periodically controlled by standard analytical methods. So it is advisable to have a rapid method that will allow PCBs determination in wide range of quantities by simple instrumentation with internal standards. The method based on perchlorination of PCBs considerably simplifies the detection of PCB congeners as compared to other techniques. In this practice all polychlorinated derivatives are converted into decachlorobiphenyl (DCB). This is followed by gas chromatography with electron capture detector (GC-ECD), which is highly sensitive for the substances of interest. Currently EPA procedure 508a (1989) is the only official screening method for detection of PCBs using perchlorination. This uses SbCl5 and powdered Fe mixture as reagent at 270 C without internal standard. We reported about using of perchlorination reagent based on mixture of powdered duralumin, sulphur and SO2Cl2 heated at 105 C for 2 h for detection of PCBs as decachlorobiphenyls in a wide range of concentration: 16.4 ng/sample to 164 {mu}/sample. 4,4'-difluorobiphenyl was proposed as internal standard that allowed to control all steps of sample preparation including perchlorination reaction. In the present work we extended our experience of perchlorination to detect the PCBs.

Influence of iron redox transformations on plutonium sorption to sediments

Energy Technology Data Exchange (ETDEWEB)

Hixon, A.E.; Powell, B.A. [Environmental Engineering and Earth Sciences, Clemson Univ., Clemson, SC (United States); Hu, Y.J.; Nitsche, H. [Dept. of Chemistry, Univ. of California, Berkeley, CA (United States); Lawrence Berkeley National Lab., Berkeley, CA (United States); Kaplan, D.I. [Savannah River National Lab., Aiken, SC (United States); Kukkadapu, R.K.; Qafoku, O. [Pacific Northwest National Lab., Richland, WA (United States)

2010-07-01

Plutonium subsurface mobility is primarily controlled by its oxidation state, which in turn is loosely coupled to the oxidation state of iron in the system. Experiments were conducted to examine the effect of sediment iron mineral composition and oxidation state on plutonium sorption and reduction. A pH 6.3 vadose zone sediment containing iron oxides and iron-containing phyllosilicates was treated with various complexants (ammonium oxalate) and reductants (hydroxylamine hydrochloride and dithionite-citrate-bicarbonate (DCB)) to selectively leach and/or reduce iron oxide and phyllosilicate/clay Fe(III). {sup 57}Fe-Moessbauer spectroscopy was used to identify initial iron mineral composition of the sediment and monitor dissolution and reduction of iron oxides and reduction of phyllosilicate Fe(III). {sup 57}Fe-Moessbauer spectroscopy showed that the Fe-mineral composition of the untreated sediment is: 25-30% hematite, 60-65% small-particle/Al-goethite, and < 10% Fe(III) in phyllosilicate; there was no detectable Fe(II). Upon reduction with a strong chemical reductant (dithionite-citrate-bicarbonate buffer), much of the hematite and goethite was removed. Partial reduction of phyllosilicate Fe(III) was evident in the sediments subjected to DCB treatment. Sorption of Pu(V) was monitored over one week for the untreated and each of five treated sediment fractions. Plutonium oxidation state speciation in the aqueous and solid phases was monitored using solvent extraction, coprecipitation, and XANES. The rate of sorption appears to correlate with the fraction of Fe(II) in the sediment (untreated or treated). Pu(V) was the only oxidation state measured in the aqueous phase, irrespective of treatment, whereas Pu(IV) and much smaller amounts of Pu(V) and Pu(VI) were measured in the solid phase. Surface-mediated reduction of Pu(V) to Pu(IV) occurred in treated and untreated sediment samples; Pu(V) remained on untreated sediment surface for two days before reducing to Pu

Evaluation of medicines advertising in medical journals

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Daliana Maria Berenice de Oliveira Souza

2009-06-01

Full Text Available This work intended to analyze the advertising of medicines requiring medical prescription, divulged into three journals of the neurology and cardiology areas addressed to healthcare professionals. The analysis was based on current legislation, among other criteria, as well as specific literature. The presence of the following items was investigated: registration number, drug name, specific indications, contraindications; cautions and warnings; adverse reactions; possible side effects; posology; legibility of technical-scientific information and bibliographic references, phrases and/or expressions about the medication benefits, as compared to other drugs; safety warnings, healing promises and pictures of people smiling, and the quotations confirmation based on bibliographic references. Among the evaluated legal criteria, it was observed the absence of legibility in technical-scientific information in 85% of advertisements; absence of side effects in 23%; absence of cautions and warnings in 15%; of contraindications in 12.8%; of posology in 6.4%; of registration numbers in 2.7% and of the Common Brazilian Denomination/Common International Denomination (Denominação Comum Brasileira/Denominação Comum Internacional - DCB/DCI in 0.6%. Out of 130 statements respecting advantages face to others drugs, 23.8% were not confirmed and out of 48 divulged safety messages, 41.7% could not be found in quoted references. The pictures of people smiling was a resource used in 42.2% of advertisements. Out of 1362 references analyzed, 19.7% were not found and 37.1% of quoted affirmations weren't confirmed.Este trabalho objetivou analisar propagandas de medicamentos sujeitos à prescrição, que foram veiculadas em três periódicos das áreas de cardiologia e neurologia, dirigidos a profissionais de saúde. A análise envolveu critérios baseados na legislação em vigor, além de outros, e das referências bibliográficas. Averiguou-se a presença dos seguintes

Mineralogia e reserva de K de Cambissolos submetidos a diferentes manejos após derrubada e queima da floresta na Amazônia Meridional Mineralogy and K reserve of Cambisols submitted to different managements after slashing and burning of the forest in the Meridional Amazon, Brazil

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Alessandro Góis Orrutéa

2012-01-01

Full Text Available As altas temperaturas ocorrentes durante a queima na floresta Amazônica podem induzir transformações mineralógicas da fração argila. Este trabalho objetivou avaliar as alterações mineralógicas nas frações areia, silte e argila e na reserva mineral de solos submetidos a diferentes manejos (11 anos de mata secundária, pastagem e café após a derrubada e queima de floresta nativa situada na Amazônia Meridional, município de Cacoal (RO. Uma área de floresta nativa ombrófila densa, com mesma feição pedológica, foi dividida em quatro partes, sendo três áreas submetidas ao corte e à queima e posteriormente cultivadas. Em cada manejo, os perfis de solos foram descritos e amostras dos horizontes A, AB, B1, 2B2 e 2BC foram coletadas para as análises mineralógicas das frações argila, silte e areia (difratometria de raios X e químicas da fração argila (extração de Fe com ditionito-citrato-bicarbonato - DCB e com oxalato de amônio - OA. Os teores de K não trocáveis foram determinados nas amostras de solo após extração com HNO3 1 mol L-1 fervente. Verificou-se o predomínio da caulinita na fração argila e alta reserva mineral de K nos solos, associada à ocorrência de mica nas frações argila, silte e areia. Os diferentes manejos não afetaram os teores de Fe2O3DCB e Fe2O3OA; por outro lado, o maior valor estimado para a relação entre os teores de goethita e hematita [Gt/(Gt+Hm] na fração argila no horizonte A da floresta indica uma possível transformação parcial de Gt em Hm durante a queima da floresta para a implantação dos manejos mata secundária, pastagem e café.The high soil temperatures that take place during the burning of the Amazon rainforest may induce soil mineralogical transformations. This study aimed to evaluate mineralogical changes in sand, silt and clay fractions and to assess K reserve of soils submitted to different managements (11 years of secondary forest, pasture and coffee plantation

Global Ionospheric Modelling using Multi-GNSS: BeiDou, Galileo, GLONASS and GPS.

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Ren, Xiaodong; Zhang, Xiaohong; Xie, Weiliang; Zhang, Keke; Yuan, Yongqiang; Li, Xingxing

2016-09-15

The emergence of China's Beidou, Europe's Galileo and Russia's GLONASS satellites has multiplied the number of ionospheric piercing points (IPP) offered by GPS alone. This provides great opportunities for deriving precise global ionospheric maps (GIMs) with high resolution to improve positioning accuracy and ionospheric monitoring capabilities. In this paper, the GIM is developed based on multi-GNSS (GPS, GLONASS, BeiDou and Galileo) observations in the current multi-constellation condition. The performance and contribution of multi-GNSS for ionospheric modelling are carefully analysed and evaluated. Multi-GNSS observations of over 300 stations from the Multi-GNSS Experiment (MGEX) and International GNSS Service (IGS) networks for two months are processed. The results show that the multi-GNSS GIM products are better than those of GIM products based on GPS-only. Differential code biases (DCB) are by-products of the multi-GNSS ionosphere modelling, the corresponding standard deviations (STDs) are 0.06 ns, 0.10 ns, 0.18 ns and 0.15 ns for GPS, GLONASS, BeiDou and Galileo, respectively in satellite, and the STDs for the receiver are approximately 0.2~0.4 ns. The single-frequency precise point positioning (SF-PPP) results indicate that the ionospheric modelling accuracy of the proposed method based on multi-GNSS observations is better than that of the current dual-system GIM in specific areas.

Skating on thin ice: surface chemistry under interstellar conditions

Science.gov (United States)

Fraser, H.; van Dishoeck, E.; Tielens, X.

Solid CO2 has been observed towards both active star forming regions and quiescent clouds (Gerakines et. al. (1999)). The high abundance of CO2 in the solid phase, and its low abundance in the gas phase, support the idea that CO2 is almost exclusively formed in the solid state. Several possible formation mechanisms have been postulated (Ruffle &Herbst (2001): Charnley &Kaufman (2000)), and the detection of CO2 towards quiescent sources such as Elias 16 (Whittet et. al. (1998)) clearly suggests that CO2 can be produced in the absence of UV or electron mediated processes. The most likely route is via the surface reactions between O atoms, or OH radicals, and CO. The tools of modern surface- science offer us the potential to determine many of the physical and chemical attributes of icy interstellar grain mantles under highly controlled conditions, that closely mimic interstellar environments. The Leiden Surface Reaction Simulation Device ( urfreside) combines UHV (UltraS High Vacuum) surface science techniques with an atomic beam to study chemical reactions occurring on the SURFACE and in the BULK of interstellar ice grain mimics. By simultaneously combining two or more surface analysis techniques, the chemical kinetics, reaction mechanisms and activation energies can be determined directly. The experiment is aimed at identifying the key barrierless reactions and desorption pathways on and in H2 O and CO ices under interstellar conditions. The results from traditional HV (high vacuum) and UHV studies of the CO + O and CO + OH reactions will be presented in this paper. Charnley, S.B., & Kaufman, M.J., 2000, ApJ, 529, L111 Gerakines, P.A., 1999, ApJ, 522, 357 Ruffle, D.P., & Herbst, E., 2001, MNRAS, 324, 1054 Whittet, D.C.B., et.al., 1998, ApJ, 498, L159

An oil palm-based biorefinery concept for cellulosic ethanol and phytochemicals production: Sustainability evaluation using exergetic life cycle assessment

International Nuclear Information System (INIS)

Ofori-Boateng, Cynthia; Lee, Keat Teong

2014-01-01

In this study, thermo-environmental sustainability of an oil palm-based biorefinery concept for the co-production of cellulosic ethanol and phytochemicals from oil palm fronds (OPFs) was evaluated based on exergetic life cycle assessment (ExLCA). For the production of 1 tonne bioethanol, the exergy content of oil palm seeds was upgraded from 236 MJ to 77,999 MJ during the farming process for OPFs production. Again, the high exergy content of the OPFs was degraded by about 62.02% and 98.36% when they were converted into cellulosic ethanol and phenolic compounds respectively. With a total exergy destruction of about 958,606 MJ (internal) and 120,491 MJ (external or exergy of wastes), the biorefinery recorded an overall exergy efficiency and thermodynamic sustainability index (TSI) of about 59.05% and 2.44 per tonne of OPFs' bioethanol respectively. Due to the use of fossil fuels, pesticides, fertilizers and other toxic chemicals during the production, the global warming potential (GWP = 2265.69 kg CO 2 eq.), acidification potential (AP = 355.34 kg SO 2 eq.) and human toxicity potential (HTP = 142.79 kg DCB eq.) were the most significant environmental impact categories for a tonne of bioethanol produced in the biorefinery. The simultaneous saccharification and fermentation (SSF) unit emerged as the most exergetically efficient (89.66%), thermodynamically sustainable (TSI = 9.67) and environmentally friendly (6.59% of total GWP) production system. -- Highlights: • Thermo-environmental sustainability of palm-based biorefinery was assessed. • OPFs' exergy content was degraded when converted into bioethanol and phytochemicals. • Exergy efficiency (59.05%) and TSI (2.44) were recorded for the biorefinery • Global warming potential of 2265.6 kg CO 2 eq. was recorded for the whole biorefinery

Characterization of Organic Thin Film Solar Cells of PCDTBT : PC71BM Prepared by Different Mixing Ratio and Effect of Hole Transport Layer

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Vijay Srinivasan Murugesan

2015-01-01

Full Text Available The organic thin film solar cells (OTFSCs have been successfully fabricated using PCDTBT : PC71BM with different mixing ratios (1 : 1 to 1 : 8 and the influence of hole transport layer thickness (PEDOT : PSS. The active layers with different mixing ratios of PCDTBT : PC71BM have been fabricated using o-dichlorobenzene (o-DCB. The surface morphology of the active layers and PEDOT : PSS layer with different thicknesses were characterized by AFM analysis. Here, we report that the OTFSCs with high performance have been optimized with 1 : 4 ratios of PCDTBT : PC71BM. The power conversion efficiency (PCE = 5.17% of the solar cells was significantly improved by changing thickness of PEDOT : PSS layer. The thickness of the PEDOT : PSS layer was found to be of significant importance; the thickness of the PEDOT : PSS layer at 45 nm (higher spin speed 5000 rpm shows higher short circuit current density (Jsc and lower series resistance (Rs and higher PCE.

Advancements in high-power high-brightness laser bars and single emitters for pumping and direct diode application

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An, Haiyan; Jiang, Ching-Long J.; Xiong, Yihan; Zhang, Qiang; Inyang, Aloysius; Felder, Jason; Lewin, Alexander; Roff, Robert; Heinemann, Stefan; Schmidt, Berthold; Treusch, Georg

2015-03-01

We have continuously optimized high fill factor bar and packaging design to increase power and efficiency for thin disc laser system pump application. On the other hand, low fill factor bars packaged on the same direct copper bonded (DCB) cooling platform are used to build multi-kilowatt direct diode laser systems. We have also optimized the single emitter designs for fiber laser pump applications. In this paper, we will give an overview of our recent advances in high power high brightness laser bars and single emitters for pumping and direct diode application. We will present 300W bar development results for our next generation thin disk laser pump source. We will also show recent improvements on slow axis beam quality of low fill factor bar and its application on performance improvement of 4-5 kW TruDiode laser system with BPP of 30 mm*mrad from a 600 μm fiber. Performance and reliability results of single emitter for multiemitter fiber laser pump source will be presented as well.

Experimental characterization of interlaminar fracture toughness of composite laminates assembled with three different carbon fiber lamina

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Domenico Gentile

2018-01-01

Full Text Available In the present work, the fracture resistance of a carbon fiber composite under mode I and mode II loading have been experimentally determined. For the mode I and II, the energy release rate G has been determinate for each material. In some cases, only a single estimation of G was possible due to problems in the propagation such as extensive fiber bridging and loss of planarity of the running crack. The experimental results relative to DCB tests have been analyzed in order to derive statistical trends. Only the samples for which more than three crack advance data points have been collected are considered in the analysis. The G values are those obtained with the compliance calibration method (CC. For ENF test, determination of critical GII, in addition to the value calculated with the relationship given in the prescription EN6034, other two values, the non linear and visual non linear, are also given. The crack propagation resulted to be unstable for all specimens tested and only a single value of GII could be determined

Fractografia de compósito estrutural aeronáutico submetido à caracterização de tenacidade à fratura interlaminar em modo I Fractography of aeronautical composite structures submitted to mode I interlaminar fracture toughness characterization

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Geraldo Maurício Cândido

2012-01-01

Full Text Available Muitos componentes das modernas aeronaves estão sendo manufaturados em compósitos poliméricos. Laminados de resina epóxi modificada reforçada com fibras de carbono contínuas são empregados em estruturas primárias e secundárias para reduzir o peso e melhorar o desempenho operacional. Porém, se ocorrer uma falha circunstancial, o processo de fratura desses laminados é complexo e pode envolver mecanismos de danos interlaminares. A delaminação é a descontinuidade interlaminar que pode se propagar de forma catastrófica com a aplicação de cargas mecânicas. O ensaio de corpos de prova denominado de Double Cantilever Beam (DCB é o método mais utilizado para determinar a tenacidade à fratura em Modo I de compósitos estruturais. Neste trabalho, amostras preparadas de um laminado de tecido bidirecional, estilo plain weave, foram submetidas ao carregamento estático de delaminação em Modo I, à temperatura ambiente. A análise fractográfica das superfícies delaminadas foi realizada por microscopia eletrônica de varredura. Os resultados mostram que o processo de fratura se inicia nas bolsas de resina após um inserto de Teflon® e se propaga ao longo das regiões ricas em resina posicionadas nos interstícios de entrelaçamento das mechas da trama e da urdidura. Os principais aspectos fractográficos revelados são identificados, documentados e discutidos neste trabalho.Many components of modern aircrafts are now manufactured from polymer composites. Reinforced laminates with continuous carbon fibers and modified epoxy resin are employed in primary and secondary structures to reduce weight and improve the aircraft performance. However, if a circumstantial failure happens, the complex fracture process of the laminates may involve interlaminar damage mechanisms. The delamination is the interlaminar discontinuity which may propagate catastrophically with the application of mechanical loads. The Double Cantilever Beam (DCB is the most

Caracterização Mecânica de Compósitos de Poliamida/Fibra de Carbono Via Ensaios de Cisalhamento Interlaminar e de Mecânica da Fratura Mechanical Characterization of Polyamide/Carbon Fiber Composites by Using Interlaminar Shear Strength and Fracture Mechanical Tests

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Edson C. Botelho

2002-01-01

Full Text Available Compósitos termoplásticos a partir de poliamidas 6 e 6,6 e tecido de fibras de carbono com 40, 50 e 60 % em volume de reforço foram processados via moldagem por compressão a quente e caracterizados por ensaios mecânicos destrutivos (cisalhamento interlaminar em três pontos (short-beam, cisalhamento interlaminar por compressão (CST e ensaios de mecânica da fratura e por inspeção não-destrutiva (ultra-som e microscopias óptica e eletrônica de varredura. Os resultados obtidos mostraram que os compósitos termoplásticos processados apresentaram uma distribuição homogênea do polímero no reforço. Entretanto, nos compósitos com maior quantidade de poliamida (40 % de reforço foram observadas regiões ricas em matriz entre as camadas de tecido. Os ensaios de mecânica da fratura (DCB e ENF e de cisalhamento interlaminar em três pontos não apresentaram falha interlaminar, não sendo observada a propagação de trincas de forma homogênea e retilínea no interior do material. Em função destes resultados foi utilizado o ensaio de cisalhamento por compressão, desenvolvido no Institute of Polymer Research Dresden da Alemanha, que permitiu uma caracterização mais precisa dos compósitos termoplásticos estudados. Foi observado também, a partir dos ensaios de CST, que os compósitos obtidos da poliamida 6,6 apresentaram um aumento no valor do cisalhamento interlaminar de até 20 % com o aumento do volume de fibras.Thermoplastics composites of polyamide 6 and 6.6 reinforced with carbon fiber fabric were obtained by compression molding and characterized by destructive (short-beam, compression shear (CST and fracture mechanics testing as well as by non-destructive inspection (ultrasound analysis, optical and scanning electron microscopy. The results show that, in general, the matrix was homogeneously distributed about the reinforcing fabric. However, for the composites with higher polyamide content (>50% matrix-rich regions were

Biodegradation of lindane using a novel yeast strain, Rhodotorula sp. VITJzN03 isolated from agricultural soil.

Science.gov (United States)

Abdul Salam, Jaseetha; Lakshmi, V; Das, Devlina; Das, Nilanjana

2013-03-01

Lindane is a notorious organochlorine pesticide due to its high toxicity, persistence in the environment and its tendency to bioaccumulate. A yeast strain isolated from sorghum cultivation field was able to use lindane as carbon and energy source under aerobic conditions. With molecular techniques, it was identified and named as Rhodotorula strain VITJzN03. The effects of nutritional and environmental factors on yeast growth and the biodegradation of lindane was investigated. The maximum production of yeast biomass along with 100 % lindane mineralization was noted at an initial lindane concentration of 600 mg l(-1) within a period of 10 days. Lindane concentration above 600 mg l(-1) inhibited the growth of yeast in liquid medium. A positive relationship was noted between the release of chloride ions and the increase of yeast biomass as well as degradation of lindane. The calculated degradation rate and half life of lindane were found to be 0.416 day(-1) and 1.66 days, respectively. The analysis of the metabolites using GC-MS identified the formation of seven intermediates including γ-pentachlorocyclohexane(γ-PCCH), 1,3,4,6-tetrachloro-1,4-cyclohexadiene(1,4-TCCHdiene), 1,2,4-trichlorobenzene (1,2,4 TCB), 1,4-dichlorobenzene (1,4 DCB), chloro-cis-1,2-dihydroxycyclohexadiene (CDCHdiene), 3-chlorocatechol (3-CC) and maleylacetate (MA) derivatives indicating that lindane degradation follows successive dechlorination and oxido-reduction. Based on the results of the present study, the possible pathway for lindane degradation by Rhodotorula sp. VITJzN03 has been proposed. To the best of our knowledge, this is the first report on lindane degradation by yeast which can serve as a potential agent for in situ bioremediation of medium to high level lindane-contaminated sites.

Gênese de horizonte coeso, fragipã e duripã em solos do tabuleiro costeiro do sul da Bahia Genesis of hardened horizons, fragipan and duripan in soils of the coastal tablelands of south Bahia

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Ana Maria Souza dos Santos Moreau

2006-12-01

toposequences were sampled and the taxonomic classes of the soils were identified as Argisolic Eutrophic Red Latosol, Latosolic Dystrophic Yellow Argisol for the first toposequence, and Abruptic Dystrophic Yellow Argisol, Dystrophic Typic Yellow Argisol and Duric Orthic Carbic Spodosol, for the second sequence. The chemical analysis performed were Fe, Si, and Al extraction with sodium dithionite-citrate-bicarbonate (DCB and ammonium oxalate. The clay fraction mineralogy was evaluated by X-ray diffraction. Soils with cohesive horizons presented very low Fe, Si, and Al contents extracted with both DCB and oxalate. Nevertheless, soil with fragipan and duripan showed high Si and Al content extracted with oxalate, indicating their role as cementing agents. The Argisol clay fraction is predominantly kaolinitic, and gibbsite was only found in the Bt1, Bt2 and Bw horizons of the Latosolic Yellow Argisol. Gibbsite was found in soils with fragipan and duripan (Duric Orthic Carbic Spodosol, and despite being considered a disorganizing agent of kaolinite adjustment, the hardpan characteristics were maintained. Thus, the hardening mechanisms of these soils seem different for cohesive, fragipan and duripan horizons.

Analysis of factors influencing the bond strength in roll bonding processes

Science.gov (United States)

Khaledi, Kavan; Wulfinghoff, Stephan; Reese, Stefanie

2018-05-01

Cold Roll Bonding (CRB) is recognized as an industrial technique in which the metal sheets are joined together in order to produce laminate metal composites. In this technique, a metallurgical bond resulting from severe plastic deformation is formed between the rolled metallic layers. The main objective of this paper is to analyse different factors which may affect the bond formation in rolling processes. To achieve this goal, first, an interface model is employed which describes both the bonding and debonding. In this model, the bond strength evolution between the metallic layers is calculated based on the film theory of bonding. On the other hand, the debonding process is modelled by means of a bilinear cohesive zone model. In the numerical section, different scenarios are taken into account to model the roll bonding process of metal sheets. The numerical simulation includes the modelling of joining during the roll bonding process followed by debonding in a Double Cantilever Beam (DCB) peeling test. In all simulations, the metallic layers are regarded as elastoplastic materials subjected to large plastic deformations. Finally, the effects of some important factors on the bond formation are numerically investigated.

A study on the fracture toughness of heavy section steel plates and forgings for nuclear pressure vessels produced in Japan, (4)

International Nuclear Information System (INIS)

Sakai, Yuzuru; Ogura, Nobukazu; Takahashi, Isao; Miya, Kenzo; Ando, Yoshio.

1985-01-01

As another parameter for evaluating the toughness of structural materials, there is crack arrest toughness. This is a parameter showing the resistance of materials to stop the cracks rapidly propagating in brittle state within the materials, unlike static and dynamic fracture toughness related to the occurrence of breaking. As the conventional method of determining the crack arrest toughness, the relatively large testing method such as double tensile test and ESSO test have been known, but the establishment of a smaller convenient testing method is desired. In this study, the evaluation of the crack arrest toughness of the very thick steel materials produced in Japan was carried out by the testing method using small test pieces. In order to make test pieces small, tapered type DCB test and the three-point bending test using DWTT test pieces were examined as well as the testing method recommended by ASTM. The test materials were A 533B, Cl. 1 and A 508, Cl. 3. The test pieces, the various testing methods and the experimental results are reported. The temperature dependence of the crack arrest toughness was shown. (Kako, I.)

Guanidinium ionic liquid-based surfactants as low cytotoxic extractants: Analytical performance in an in-situ dispersive liquid-liquid microextraction method for determining personal care products.

Science.gov (United States)

Pacheco-Fernández, Idaira; Pino, Verónica; Ayala, Juan H; Afonso, Ana M

2017-05-01

The IL-based surfactant octylguanidinium chloride (C 8 Gu-Cl) was designed and synthetized with the purpose of obtaining a less harmful surfactant: containing guanidinium as core cation and a relatively short alkyl chain. Its interfacial and aggregation behavior was evaluated through conductivity and fluorescence measurements, presenting a critical micelle concentration value of 42.5 and 44.6mmolL -1 , respectively. Cytotoxicity studies were carried out with C 8 Gu-Cl and other IL-based and conventional surfactants, specifically the analogue 1-octyl-3-methylimidazolium chloride (C 8 MIm-Cl), and other imidazolium- (C 16 MIm-Br) and pyridinium- (C 16 Py-Cl) based surfactants, together with the conventional cationic CTAB and the conventional anionic SDS. From these studies, C 8 Gu-Cl was the only one to achieve the classification of low cytotoxicity. An in situ dispersive liquid-liquid microextraction (DLLME) method based on transforming the water-soluble C 8 Gu-Cl IL-based surfactant into a water-insoluble IL microdroplet via a simple metathesis reaction was then selected as the extraction/preconcentration method for a group of 6 personal care products (PCPs) present in cosmetic samples. The method was carried out in combination with high-performance liquid chromatography (HPLC) and diode array detection (DAD). The method was properly optimized, requiring the use of only 30μL of C 8 Gu-Cl for 10mL of aqueous sample with a NaCl content of 8% (w/v) to adjust the ionic strength and pH value of 5. The metathesis reaction required the addition of the anion exchange reagent (bis[(trifluoromethyl)sulfonyl]imide - 1:1 molar ratio), followed by vortex and centrifugation, and dilution of the final microdroplet up to 60μL with acetonitrile before the injection in the HPLC-DAD system. The optimum in situ DLLME-HPLC-DAD method takes ∼10min for the extraction step and ∼22min for the chromatographic separation, with analytical features of low detection limits: down to 0.4�

Personal exposure to mixtures of volatile organic compounds: modeling and further analysis of the RIOPA data.

Science.gov (United States)

Batterman, Stuart; Su, Feng-Chiao; Li, Shi; Mukherjee, Bhramar; Jia, Chunrong

2014-06-01

-parametric Dirichlet process mixture (DPM) of normal distributions for three individual VOCs (chloroform, 1,4-DCB, and styrene). Goodness of fit for these full distribution models was also evaluated using simulated data. Specific Aim 2. Mixtures in the RIOPA VOC data set were identified using positive matrix factorization (PMF) and by toxicologic mode of action. Dependency structures of a mixture's components were examined using mixture fractions and were modeled using copulas, which address correlations of multiple components across their entire distributions. Five candidate copulas (Gaussian, t, Gumbel, Clayton, and Frank) were evaluated, and the performance of fitted models was evaluated using simulation and mixture fractions. Cumulative cancer risks were calculated for mixtures, and results from copulas and multivariate lognormal models were compared with risks based on RIOPA observations. Specific Aim 3. Exposure determinants were identified using stepwise regressions and linear mixed-effects models (LMMs). Specific Aim 1. Extreme value exposures in RIOPA typically were best fitted by three-parameter generalized extreme value (GEV) distributions, and sometimes by the two-parameter Gumbel distribution. In contrast, lognormal distributions significantly underestimated both the level and likelihood of extreme values. Among the VOCs measured in RIOPA, 1,4-dichlorobenzene (1,4-DCB) was associated with the greatest cancer risks; for example, for the highest 10% of measurements of 1,4-DCB, all individuals had risk levels above 10(-4), and 13% of all participants had risk levels above 10(-2). Of the full-distribution models, the finite mixture of normal distributions with two to four clusters and the DPM of normal distributions had superior performance in comparison with the lognormal models. DPM distributions provided slightly better fit than the finite mixture distributions; the advantages of the DPM model were avoiding certain convergence issues associated with the finite mixture

Adsorção de fósforo em solos de argila de atividade baixa Phosphate sorption in low activity clay soils

Directory of Open Access Journals (Sweden)

Gustavo Souza Valladares

2003-01-01

Full Text Available Neste estudo foram avaliadas possíveis correlações entre atributos físicos e químicos do solo e a capacidade máxima de adsorção de fósforo (CMAP em solos com argila de atividade baixa de diferentes regiões do Brasil, sendo utilizadas amostras de horizontes superficiais (A e subsuperficiais (B de 16 perfis de solos. As doses para a determinação da CMAP foram calculadas com base no teor de fósforo remanescente e variaram de 0 a 135 mg.L-1. A partir dos dados obtidos foram então construídas isotermas de adsorção de Langmuir. Foram feitas correlações entre CMAP e os teores de argila, de carbono orgânico, ki, kr, superfície específica, teor de alumínio determinado por ataque sulfúrico e teores das diferentes formas de ferro extraível. Foi observada grande variação nos valores de CMAP para o horizonte superficial (48 a 1429 mg.kg-1 e para o horizonte subsuperficial (455 e 1.667 mg.kg-1. Os coeficientes de correlação demonstraram haver uma associação significativa entre a CMAP e o teor de argila dos solos, ferro e alumínio, determinados pelo ataque sulfúrico e ferro extraído com ditionito-citrato-bicarbonato (DCB. A análise de regressão múltipla mostrou bom ajuste aos valores da CMAP com base em atributos dos solos estudados.In this study possible correlations between physical and chemical properties and the maximum phosphorus adsorption capacity (MAPC were evaluated in soils with low activity clay from different regions of Brazil, using samples from the surface (A and subsurface (B horizons of 16 soil profiles. The dosages for the determination of MAPC were calculated from the level of remaining phosphorus and they ranged from 0 to 135 mg L-1. From this data isotherms of P adsorption were built. Correlations were tested between MAPC and the clay content, organic carbon, ki, kr, specific surface, Al content determined by sulfuric acid attack, and content of different forms of extracted iron. A high variation in the

U(VI) adsorption on natural iron-coated sands: comparison of approaches for modeling adsorption on heterogeneous environmental materials

International Nuclear Information System (INIS)

Logue, Brian A.; Smith, Robert W.; Westall, John C.

2004-01-01

Adsorption of U(VI) on 6 samples of natural Fe-rich sands from Oyster, VA was studied over a range of U(VI) concentrations (0.1-100 μM), pH values (3-7.6), and dithionite-citrate-bicarbonate (DCB) extractable amounts of Fe (3.1-12.3 μmol/g). Four modeling approaches were applied to represent the U(VI) adsorption data. Model I was a two-site, diffuse double layer, surface complexation model based on data for synthetic ferrihydrite [Geochim. Cosmochim. Acta 58 (1994) 5465-5478]. Considering the magnitude of approximations necessary for application of the laboratory-based model to natural sands, Model I was surprisingly accurate, as determined by the goodness of fit parameter, χ 2 /N of 53.1-22.2. Model II was based on the reactions and diffuse double layer treatment of Model I, but was calibrated to a portion of U(VI) adsorption data for each sand, and then used to predict adsorption data for the same sand under different experimental conditions. Model II did not increase the accuracy of the predictions made with Model I, χ 2 /N of 42.4-27.6. Models III and IV were four-site affinity spectrum models, without an explicit electric double layer model or explicit surface hydrolysis reactions. Model III was based on a discrete log K spectrum approach, and Model IV was obtained from adjusting all surface stability constants and site concentrations for all surface sites. Models III and IV represented the U(VI) adsorption data with the greatest accuracy, χ 2 /N ranged from 13.8 to 4.4. Model I provides evidence supporting the practice of using pure phase thermodynamic reaction constants for describing the adsorption characteristics of environmentally important sorbents in certain simple cases. Yet, affinity spectrum approaches (Models III and IV) become increasingly important as more accurate interpolation of adsorption data is necessary, the sorbent becomes increasingly complex, or the range of experimental conditions expands

A specialist’s audit of aggregated occurrence records: An ‘aggregator’s’ perspective

Directory of Open Access Journals (Sweden)

Lee Belbin

2013-05-01

Full Text Available A recent ZooKeys’ paper (Mesibov, 2013: http://www.pensoft.net/journal_home_page.php?journal_id=1&page=article&SESID=df7bcb35b02603283dcb83ee0e0af0c9&type=show&article_id=5111 has highlighted data quality issues in aggregated data sets, but did not provide a realistic way to address these issues. This paper provides an aggregator’s perspective including ways that the whole community can help to address data quality issues. The establishment of GBIF and national nodes (national aggregators such as the Atlas of Living Australia (ALA have integrated and exposed a huge diversity of biological observations along with many associated issues. Much of the admirable work by Mesibov (2013 was enabled bythe data exposed.Data quality, one of the highest priorities for GBIF, the national nodes and other aggregators, depends on both automatic methods and community experts to detect and correct data issues. Not all issues can however be automatically detected or corrected, so community assistance is needed to help improve the quality of exposed biological data. We do need to improve the infrastructure and associated processes to more easily identify data issues and document all changes to ensure a full record is permanently and publicly available.

Dynamic fracture toughness testing of structural steels

International Nuclear Information System (INIS)

Debel, C.P.

1978-01-01

Two candidate test methods aimed at producing materials properties of interest in connection with crack arrest assessments are currently under evaluation. These methods and the significance of the results are described. The quasi-static as well as the dynamic fracture toughness of a plain C-Mn steel in the as-quenched and tempered condition have been examined at temperatures between -115 0 C and the ambient temperature. Wedge-loaded duplex DCB-specimens were used in dynamic tests. The crack extension velocity was measured using a surface deposited grid and a registration circuit based on TTL-electronics. The toughness transition-temperature at quasi-static loading rate is found to be low; but during dynamic crack-extension a substantial shift of the transition-region to higher temperatures is produced, and fast fracture was obtained even at ambient temperature. Even though the dynamic fracture toughness Ksub(ID) increases with temperature, it decreases with increasing crack-extension velocity at a given temperature and the rate of decrease with respect to crack-extension velocity seems to be independent of temperature. Ksub(ID) appears to be insensitive to heat treatments. Test results indicate insufficient load-train stiffness, and problems due to crack branching were encountered. (author)

Iodine induced stress corrosion cracking of zircaloy cladding tubes

International Nuclear Information System (INIS)

Brunisholz, L.; Lemaignan, C.

1984-01-01

Iodine is considered as one of the major fission products responsible for PCI failure of Zry cladding by stress corrosion cracking (SCC). Usual analysis of SCC involves both initiation and growth as sequential processes. In order to analyse initiation and growth independently and to be able to apply the procedures of fracture mechanics to the design of cladding, with respect to SCC, stress corrosion tests of Zry cladding tubes were undertaken with a small fatigue crack (approx. 200 μm) induced in the inner wall of each tube before pressurization. Details are given on the techniques used to induce the fatigue crack, the pressurization test procedure and the results obtained on stress releaved or recrystallized Zry 4 tubings. It is shown that the Ksub(ISCC) values obtained during these experiments are in good agreement with those obtained from large DCB fracture mechanics samples. Conclusions will be drawn on the applicability of linear elastic fracture mechanics (LEFM) to cladding design and related safety analysis. The work now underway is aimed at obtaining better understanding of the initiation step. It includes the irradiation of Zry samples with heavy ions to simulate the effect of recoil fragments implanted in the inner surface of the cladding, that could create a brittle layer of about 10 μm

Facial dimensions, bite force and masticatory muscle thickness in preschool children with functional posterior crossbite

Directory of Open Access Journals (Sweden)

Paula Midori Castelo

2008-03-01

Full Text Available Posterior crossbite may affect craniofacial growth and development. Thus, this study aimed to associate facial dimensions (by standardized frontal photographs to masseter and anterior portion of the temporal muscle thickness (by ultrasonography and maximal bilateral bite force in 49 children with deciduous and early mixed dentitions. They were distributed in four groups: deciduous-normal occlusion (DNO, n = 15, deciduous-crossbite (DCB, n = 10, mixed-normal occlusion (MNO, n = 13 and mixed-crossbite (MCB, n = 11. Anterior facial height (AFH, bizygomatic width (FWB, and intergonial width (FWI were determined and associated with muscle thickness and bite force, applying Pearson’s coefficients and multiple logistic regression, with age, gender, body weight and height as the covariates. FWB and FWI were correlated positively with the masseter thickness, whereas AFH/FWB and AFH/FWI ratios had negative correlation, except in the DNO group. The correlation between AFH/FWB and bite force in the MCB group was significantly negative. A higher AFH/FWB in MNO and MCB led to a significantly higher probability for functional crossbite development. In the studied sample, it was observed that children in the early mixed dentition with a long-face trend showed lower bite force and higher probability to present functional posterior crossbite, without significant influence of the covariates.

Distribution and Influence of Iron Phases on the Physico-Chemical Properties of Phyllosilicates

Institute of Scientific and Technical Information of China (English)

MERVAT SAID HASSAN; SAYED MAHMOUD SALEM

2002-01-01

Clay minerals from different Cretaceous stratigraphic successions of Egypt were investigated using XRD, DTA, dissolution analysis (DCB), IR, Mossbauer and X-band Electron Spin Resonance (ESR) spectroscopies. The purity of the samples and the degree of structural order were determined by XRD. The location of Fe in the octahedral sheet is characterized by absorption bands at ～875 cm-1 assigned as Al-OH-Fe which is present after chemical dissolution of free iron. The Mossbauer spectra of these clays show two doublets with isomer shift and quadrupole splitting typical of octahedral coordinated Fe3+, in addition to third doubler with hyperfine parameter typical of Fe2+ in the spectra of Abu-Had kaolinite (H) sample. 6-lines magnetic hyperfine components which are consistent with those of hematite are confirmed in the spectra of both Isel and Rish kaolinite samples. Goethite was confirmed by both IR and DTA. Multiple nature of ESR of these clays suggested structural Fe in distorted octahedral symmetry and as non-structural Fe.Little dispersion and low swelling indices as well as incomplete activation of investigated montmorillonite samples by NaCO3 appear to be due to incomplete disaggregation of montmorillonite particles. This can be explained by the ability of Fe-gel to aggregate the montmorillonite into pseudo-particles and retard the rigid-gel structure. However, extraction of this ferric amorphous compound by dithonite treatment recovers the surface properties of the montmorillonite samples.On the other hand, amounts and site occupation of Fe associated with kaolinite samples show a negative correlation with the parameters used to describe the degree of crystalline perfection, color, brightness and vitrification range of these kaolinite samples.

Distribution and Influence of Iron Phases the Physico—Chemical Properties of Phyllosilicates

Institute of Scientific and Technical Information of China (English)

MERVATSAIDHASSAN; SAYEDMAHMOUDSALEM

2001-01-01

Clay minerals from different Cretaceous stratigraphic successions of Egypt were investigated using XRD,DTA,dissolution analysis(DCB),IR,Moessbauer and X-ray Electron Spin Resonance(ESR) spectroscopes.The purity of the samples and the degree of their structural order were determined by XRD.The location of Fe in the octahedral sheet is characterized by absorption bands at-875cm-1 assigned as Al-OH-Fe which persist after chemical dissolution of free iron.The Moessbauer spectra of these clays show two doublets with isomer shift and quadrupole splitting typical of octahedrally coordinated Fe3+,in addition to third doublet with hyperfine parameter typical of Fe2+ in the spectra of Abu-Had kaolinite (H) sample.Six-lines magnetic hyperfine components which are consistent with those of hematite are confirmed in the spectra of both Isel and Rish kaolinite samples.Goethite was confirmed by both IR and DTA.Multiple nature of ESR of these clays suggested structural Fe in distorted octahedral symmetry as well as non-structural Fe.Little dispersion and low swelling indices as well as incomplete activation of the investigated montmorillonite samplas by NaCO3 appear to be due to incomplete disaggregation of montmorillonite particles.This can be explained by the ability of Fe-gel to aggregate the montmorillonite into pseudo-particles and retard the rigid-gel structure.However,extraction of this ferric amorphous compound by dithonite treatment recovers the surface properties of the montmorillonite samples.On the other hand,the amount and site occupation of Fe associated with kaolinite samples show an inverse correlation with the parameters used to describe the degree of crystallinity perfection,color,brightness and vitrification range of these kaolinite samples.

Distribution and Influence of Iron Phases on the Physico-Chemical Properties of Phyllosilicates

Institute of Scientific and Technical Information of China (English)

MERVAT SAID HASSAN; SAYED MAHMOUD SALEM

2001-01-01

Clay minerals from different Cretaceous stratigraphic successions of Egypt were investigated using XRD, DTA, dissolution analysis (DCB), IR, Mossbauer and X-ray Electron Spin Resonance (ESR) spectroscopes. The purity of the samples and the degree of their structural order were determined by XRD. The location of Fe in the octahedral sheet is characterized by absorption bands at ～875cm-1 assigned as Al-OH-Fe which persist after chemical dissolution of free iron. The Mossbauer spectra of these clays show two doublets with isomer shift and quadrupole splitting typical of octahedrally coordinated Fe3 + , in addition to third doublet with hyperfine parameter typical of Fe2+ in the spectra of Abu-Had kaolinite (H) sample. Six-lines magnetic hyperfine components which are consistent with those of hematite are confirmed in the spectra of both Isel and Rish kaolinite samples. Goethite was confirmed by both IR and DTA. Multiple nature of ESR of these clays suggested structural Fe in distorted octahedral symmetry as well as non-structural Fe.Little dispersion and low swelling indices as well as incomplete activation of the investigated montmorillonite samples by NaCO3 appear to be due to incomplete disaggregation of montmorillonite particles. This can be explained by the ability of Fe-gel to aggregate the montmorillonite into pseudo-particles and retard the rigid-gel structure. However, extraction of this ferric amorphous compound by dithonite treatment recovers the surface properties of the montmorillonite samples.On the other hand, the amount and site occupation of Fe associated with kaolinite samples show an inverse correlation with the parameters used to describe the degree of crystallinity perfection, color, brightness and vitrification range of these kaolinite samples.

Distribution and Influence of Iron Phases on the Physico—Chemical Properties of Phyllosilicates

Institute of Scientific and Technical Information of China (English)

MERVATSAIDHASSAN; SAYEDMAHMOUDSALEM

2002-01-01

Clay minerals from different Cretaceous stratigraphic successions of Egypt were investigated using XRD,DTA,dissolution analysis(DCB),IR,Moessbauer and X-band Electron Spin Resonance(ESR) spectroscopies.The purity of the samples and the degree of structural order were determined by XRD.The location of Fe in the octahedral sheet is characterized by absorption bands at-875cm-1 assigned as Al-OH-Fe which is present after chemical dissolution of free iron.The Moessbauer spectra of these clays sow two doublets with isomer shift and quadrupole splitting typical of octahedral coordinated Fe3+,in addition to third doubler with hyperfine parameter typical of Fe2+ in the spectra of Abu-Had kaolinite (H)sample.6-lines magnetic hyperfine components which are consistent with those of hematite are confirmed in the spectra of both Isel and Rish kaolinite samples.Goethite was confirmed by both IR and DTA.Multiple nature of ESR of these clays suggested structural Fe in distorted octaedral symmetry and as non-structural Fe.Little dispersion and low swelling indices as well as incomplete activaiton of investigated montmorillonite samples by NaCO3 appear to be due to incomplete disaggregation of montmorillonite particles.This can be explained by the ability of Fe-gel to aggregate the montmorillonite into pseudo-particles and retard the rigid-gel structure.However,extraction of this ferric amorphous compound by dithonite treatment recovers the surface properties of the montmorillonite samples.On the other hand,amounts and site occupation of Fe associated with kaolinite samples show a negative correlation with the parameters used to describe the degree of crystalline perfection,color,brightness and vitrification range of these kaolinite samples.

Probing Properties of Glassy Water and Other Liquids with Site Selective Spectroscopies

Energy Technology Data Exchange (ETDEWEB)

Dang, Nhan Chuong [Iowa State Univ., Ames, IA (United States)

2005-01-01

The standard non-photochemical hole burning (NPHB) mechanism, which involves phonon-assisted tunneling in the electronically excited state, was originally proposed to explain the light-induced frequency change of chemically stable molecules in glassy solids at liquid helium temperatures by this research group more than two decades ago. The NPHB mechanism was then further elucidated and the concept of intrinsic to glass configurational relaxation processes as pre-mediating step to the hole burning process was introduced. The latter provided the theoretical basis for NPHB to evolve into a powerful tool probing the dynamics and nature of amorphous media, which aside from ''simple'' inorganic glasses may include also ''complex'' biological systems such as living cells and cancerous/normal tissues. Presented in this dissertation are the experimental and theoretical results of hole burning properties of aluminum phthalocyanine tetrasulphonate (APT) in several different matrices: (1) hyperquenched glassy water (HGW); (2) cubic ice (I_c); and (3) water confined into poly(2-hydroxyethylmethacrylate) (poly-HEMA). In addition, results of photochemical hole burning (PHB) studies obtained for phthalocyanine tetrasulphonate (P_cT) in HGW and free base phthalocyanine (P_c) in ortho-dichlorobenzene (DCB) glass are reported. The goal of this dissertation was to provide further evidence supporting the NPHB mechanism and to provide more insight that leads to a better understanding of the kinetic events (dynamics) in glasses, and various dynamical processes of different fluorescent chromorphores in various amorphous solids and the liquid that exist above the glass transition temperature (T_g). The following issues are addressed in detail: (1) time evolution of hole being burned under different conditions and in different hole burning systems; (2) temperature dependent hole profile; and (3) the structure

Personal Exposure to Mixtures of Volatile Organic Compounds: Modeling and Further Analysis of the RIOPA Data

Science.gov (United States)

Batterman, Stuart; Su, Feng-Chiao; Li, Shi; Mukherjee, Bhramar; Jia, Chunrong

2015-01-01

semi-parametric Dirichlet process mixture (DPM) of normal distributions for three individual VOCs (chloroform, 1,4-DCB, and styrene). Goodness of fit for these full distribution models was also evaluated using simulated data. Specific Aim 2 Mixtures in the RIOPA VOC data set were identified using positive matrix factorization (PMF) and by toxicologic mode of action. Dependency structures of a mixture’s components were examined using mixture fractions and were modeled using copulas, which address correlations of multiple components across their entire distributions. Five candidate copulas (Gaussian, t, Gumbel, Clayton, and Frank) were evaluated, and the performance of fitted models was evaluated using simulation and mixture fractions. Cumulative cancer risks were calculated for mixtures, and results from copulas and multivariate lognormal models were compared with risks based on RIOPA observations. Specific Aim 3 Exposure determinants were identified using stepwise regressions and linear mixed-effects models (LMMs). RESULTS Specific Aim 1 Extreme value exposures in RIOPA typically were best fitted by three-parameter generalized extreme value (GEV) distributions, and sometimes by the two-parameter Gumbel distribution. In contrast, lognormal distributions significantly underestimated both the level and likelihood of extreme values. Among the VOCs measured in RIOPA, 1,4-dichlorobenzene (1,4-DCB) was associated with the greatest cancer risks; for example, for the highest 10% of measurements of 1,4-DCB, all individuals had risk levels above 10−4, and 13% of all participants had risk levels above 10−2. Of the full-distribution models, the finite mixture of normal distributions with two to four clusters and the DPM of normal distributions had superior performance in comparison with the lognormal models. DPM distributions provided slightly better fit than the finite mixture distributions; the advantages of the DPM model were avoiding certain convergence issues associated

Structures of three members of Pfam PF02663 (FmdE) implicated in microbial methanogenesis reveal a conserved α+β core domain and an auxiliary C-terminal treble-clef zinc finger

International Nuclear Information System (INIS)

Axelrod, Herbert L.; Das, Debanu; Abdubek, Polat; Astakhova, Tamara; Bakolitsa, Constantina; Carlton, Dennis; Chen, Connie; Chiu, Hsiu-Ju; Clayton, Thomas; Deller, Marc C.; Duan, Lian; Ellrott, Kyle; Farr, Carol L.; Feuerhelm, Julie; Grant, Joanna C.; Grzechnik, Anna; Han, Gye Won; Jaroszewski, Lukasz; Jin, Kevin K.; Klock, Heath E.; Knuth, Mark W.; Kozbial, Piotr; Krishna, S. Sri; Kumar, Abhinav; Lam, Winnie W.; Marciano, David; McMullan, Daniel; Miller, Mitchell D.; Morse, Andrew T.; Nigoghossian, Edward; Nopakun, Amanda; Okach, Linda; Puckett, Christina; Reyes, Ron; Sefcovic, Natasha; Tien, Henry J.; Trame, Christine B.; Bedem, Henry van den; Weekes, Dana; Wooten, Tiffany; Xu, Qingping; Hodgson, Keith O.; Wooley, John; Elsliger, Marc-André; Deacon, Ashley M.; Godzik, Adam; Lesley, Scott A.; Wilson, Ian A.

2010-01-01

The first structures from the FmdE Pfam family (PF02663) reveal that some members of this family form tightly intertwined dimers consisting of two domains (N-terminal α+β core and C-terminal zinc-finger domains), whereas others contain only the core domain. The presence of the zinc-finger domain suggests that some members of this family may perform functions associated with transcriptional regulation, protein–protein interaction, RNA binding or metal-ion sensing. Examination of the genomic context for members of the FmdE Pfam family (PF02663), such as the protein encoded by the fmdE gene from the methanogenic archaeon Methanobacterium thermoautotrophicum, indicates that 13 of them are co-transcribed with genes encoding subunits of molybdenum formylmethanofuran dehydrogenase (EC 1.2.99.5), an enzyme that is involved in microbial methane production. Here, the first crystal structures from PF02663 are described, representing two bacterial and one archaeal species: B8FYU2-DESHY from the anaerobic dehalogenating bacterium Desulfitobacterium hafniense DCB-2, Q2LQ23-SYNAS from the syntrophic bacterium Syntrophus aciditrophicus SB and Q9HJ63-THEAC from the thermoacidophilic archaeon Thermoplasma acidophilum. Two of these proteins, Q9HJ63-THEAC and Q2LQ23-SYNAS, contain two domains: an N-terminal thioredoxin-like α+β core domain (NTD) consisting of a five-stranded, mixed β-sheet flanked by several α-helices and a C-terminal zinc-finger domain (CTD). B8FYU2-DESHY, on the other hand, is composed solely of the NTD. The CTD of Q9HJ63-THEAC and Q2LQ23-SYNAS is best characterized as a treble-clef zinc finger. Two significant structural differences between Q9HJ63-THEAC and Q2LQ23-SYNAS involve their metal binding. First, zinc is bound to the putative active site on the NTD of Q9HJ63-THEAC, but is absent from the NTD of Q2LQ23-SYNAS. Second, whereas the structure of the CTD of Q2LQ23-SYNAS shows four Cys side chains within coordination distance of the Zn atom, the structure

Performance of some transgenic cotton cultivars against insect pest complex, virus incidence and yield

International Nuclear Information System (INIS)

Babar, T.K.; Karar, H.; Hasnain, M.; Saleem, M.; Ali, A.

2013-01-01

Five cultivars of cotton i.e., IR4-NIBGE, IR5-NIBGE Bt-121, Sitara-10M and Sitara-11M were screened for resistance against insect pest complex and Cotton Leaf Curl Virus (CLCuV) incidence in the research area of Cotton Research Station, Multan. The result depicted that the most resistant variety against jassids was IR4-NIBGE and Sitara-11M whereas IR4-NIBGE showed the maximum resistance against whitefly infestation. The least susceptible variety to the infestation of thrips was Sitara-10M. The most susceptible variety to the prevalence of Red Cotton Bug (RCB) was IR4-NIBGE. The genotype Bt-121 showed the attack of spotted bollworm. The high population of Dusky Cotton Bug (DCB) was observed on Bt-121 throughout the season. The incidence of virus percentage increased with the passage of time; however, the variety IR5-NIBGE exhibited maximum level of tolerance. Variety Bt-121 gave the maximum yield i.e., 1852 kg per acre followed by IR5-NIBGE, Sitara-11M, Sitara-10M 1584, 1503, 1466 kg per acre respectively. Our results suggest that IR4-NIBGE and Sitara -11M are comparatively tolerant to jassids and whitefly which are the yield losing pest. So IR4-NIBGE and Sitara -11M varieties can be included in IPM programme for the management of these voracious pests. (author)

Reductive dehalogenation activity of indigenous microorganism in sediments of the Hackensack River, New Jersey.

Science.gov (United States)

Sohn, Seo Yean; Häggblom, Max M

2016-07-01

Organohalogen pollutants are of concern in many river and estuarine environments, such as the New York-New Jersey Harbor estuary and its tributaries. The Hackensack River is contaminated with various metals, hydrocarbons and halogenated organics, including polychlorinated biphenyls (PCBs) and polychlorinated dibenzo-p-dioxins. In order to examine the potential for microbial reductive dechlorination by indigenous microorganisms, sediment samples were collected from five different estuarine locations along the Hackensack River. Hexachlorobenzene (HCB), hexabromobenzene (HBB), and pentachloroaniline (PCA) were selected as model organohalogen pollutants to assess anaerobic dehalogenating potential. Dechlorinating activity of HCB and PCA was observed in sediment microcosms for all sampling sites. HCB was dechlorinated via pentachlorobenzene (PeCB) and trichlorobenzene (TriCB) to dichlorobenzene (DCB). PCA was dechlorinated via tetrachloroaniline (TeCA), trichloroanilines (TriCA), and dichloroanilines (DCA) to monochloroaniline (MCA). No HBB debromination was observed over 12 months of incubation. However, with HCB as a co-substrate slow HBB debromination was observed with production of tetrabromobenzene (TeBB) and tribromobenzene (TriBB). Chloroflexi specific 16S rRNA gene PCR-DGGE followed by sequence analysis detected Dehalococcoides species in sediments of the freshwater location, but not in the estuarine site. Analysis targeting 12 putative reductive dehalogenase (rdh) genes showed that these were enriched concomitant with HCB or PCA dechlorination in freshwater sediment microcosms. Copyright © 2016 Elsevier Ltd. All rights reserved.

Microbial reductive dehalogenation.

Science.gov (United States)

Mohn, W W; Tiedje, J M

1992-01-01

A wide variety of compounds can be biodegraded via reductive removal of halogen substituents. This process can degrade toxic pollutants, some of which are not known to be biodegraded by any other means. Reductive dehalogenation of aromatic compounds has been found primarily in undefined, syntrophic anaerobic communities. We discuss ecological and physiological principles which appear to be important in these communities and evaluate how widely applicable these principles are. Anaerobic communities that catalyze reductive dehalogenation appear to differ in many respects. A large number of pure cultures which catalyze reductive dehalogenation of aliphatic compounds are known, in contrast to only a few organisms which catalyze reductive dehalogenation of aromatic compounds. Desulfomonile tiedjei DCB-1 is an anaerobe which dehalogenates aromatic compounds and is physiologically and morphologically unusual in a number of respects, including the ability to exploit reductive dehalogenation for energy metabolism. When possible, we use D. tiedjei as a model to understand dehalogenating organisms in the above-mentioned undefined systems. Aerobes use reductive dehalogenation for substrates which are resistant to known mechanisms of oxidative attack. Reductive dehalogenation, especially of aliphatic compounds, has recently been found in cell-free systems. These systems give us an insight into how and why microorganisms catalyze this activity. In some cases transition metal complexes serve as catalysts, whereas in other cases, particularly with aromatic substrates, the catalysts appear to be enzymes. Images PMID:1406492

Caspase inhibitors affect the kinetics and dimensions of tracheary elements in xylogenic Zinnia (Zinnia elegans cell cultures

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Schel Jan HN

2010-08-01

Full Text Available Abstract Background The xylem vascular system is composed of fused dead, hollow cells called tracheary elements (TEs that originate through trans-differentiation of root and shoot cambium cells. TEs undergo autolysis as they differentiate and mature. The final stage of the formation of TEs in plants is the death of the involved cells, a process showing some similarities to programmed cell death (PCD in animal systems. Plant proteases with functional similarity to proteases involved in mammalian apoptotic cell death (caspases are suggested as an integral part of the core mechanism of most PCD responses in plants, but participation of plant caspase-like proteases in TE PCD has not yet been documented. Results Confocal microscopic images revealed the consecutive stages of TE formation in Zinnia cells during trans-differentiation. Application of the caspase inhibitors Z-Asp-CH2-DCB, Ac-YVAD-CMK and Ac-DEVD-CHO affected the kinetics of formation and the dimensions of the TEs resulting in a significant delay of TE formation, production of larger TEs and in elimination of the 'two-wave' pattern of TE production. DNA breakdown and appearance of TUNEL-positive nuclei was observed in xylogenic cultures and this was suppressed in the presence of caspase inhibitors. Conclusions To the best of our knowledge this is the first report showing that caspase inhibitors can modulate the process of trans-differentiation in Zinnia xylogenic cell cultures. As caspase inhibitors are closely associated with cell death inhibition in a variety of plant systems, this suggests that the altered TE formation results from suppression of PCD. The findings presented here are a first step towards the use of appropriate PCD signalling modulators or related molecular genetic strategies to improve the hydraulic properties of xylem vessels in favour of the quality and shelf life of plants or plant parts.

B7h-expressing dendritic cells and plasma B cells mediate distinct outcomes of ICOS costimulation in T cell-dependent antibody responses

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Larimore Kevin

2012-06-01

Full Text Available Abstract Background The ICOS-B7h costimulatory receptor-ligand pair is required for germinal center formation, the production of isotype-switched antibodies, and antibody affinity maturation in response to T cell-dependent antigens. However, the potentially distinct roles of regulated B7h expression on B cells and dendritic cells in T cell-dependent antibody responses have not been defined. Results We generated transgenic mice with lineage-restricted B7h expression to assess the cell-type specific roles of B7h expression on B cells and dendritic cells in regulating T cell-dependent antibody responses. Our results show that endogenous B7h expression is reduced on B cells after activation in vitro and is also reduced in vivo on antibody-secreting plasma B cells in comparison to both naïve and germinal center B cells from which they are derived. Increasing the level of B7h expression on activated and plasma B cells in B-B7hTg mice led to an increase in the number of antibody-secreting plasma cells generated after immunization and a corresponding increase in the concentration of antigen-specific high affinity serum IgG antibodies of all isotypes, without affecting the number of responding germinal center B cells. In contrast, ICOS costimulation mediated by dendritic cells in DC-B7hTg mice contributed to germinal center formation and selectively increased IgG2a production without affecting the overall magnitude of antibody responses. Conclusions Using transgenic mice with lineage-restricted B7h expression, we have revealed distinct roles of ICOS costimulation mediated by dendritic cells and B cells in the regulation of T cell-dependent antibody responses.

Nano-Reinforcement of Interfaces in Prepreg-Based Composites Using a Carbon Nanotubes Spraying Method

KAUST Repository

Almuhammadi, Khaled

2012-11-01

Multi-scale reinforcement of composite materials is a topic a great interest owing to the several advantages provided, e.g. increased stiffness, improved aging resistance, and fracture toughness. It is well known, that the fracture toughness of epoxy resins used as matrix materials for CFRP composites can be increased by the addition of nano-sized fillers such as Carbon nanotubes (CNTs). CNTs are particularly well suited for this purpose because of their nano-scale diameter and high aspect ratio which allow enhancing the contact area and adhesion to the epoxy matrix. On the other hand, CNTs can also be used to improve the interlaminar strength of composite, which is the resistance offered to delamination. Several fabrication techniques have been devised to this purpose, such as powder dispersion [51-53], spraying [54], roll coating [2] and electrospinning [55, 56]. The aim of this work is to extend the knowledge in this field. In particular, MWCNTs were dispersed throughout the interface of a carbon fiber composite laminate ([0o]16) through spraying and the resulting fracture toughness was investigated in detail. To this purpose, Double Cantilever Beam (DCB) specimens were fabricated by placing 0.5 wt.% CNTs at the interface of mid-plane plies and the fracture toughness was determined using the ASTM standard procedures. For comparison, baseline samples were prepared using neat prepregs. In order to corroborate the variation of fracture toughness to the modifications of interfacial damage mechanisms, Scanning Electron Microscopy (SEM) of the failed surfaces was also undertaken. The results of this work have shown that functionalized MWCNTs can enhance the interlaminar fracture toughness; indeed, compared to the neat case, an average increase around 17% was observed. The SEM analysis revealed that the improved fracture toughness was related to the ability of the Nano-reinforcement to spread the damage through crack bridging, i.e. CNTs pull-out and peeling.

Biogeochemistry of Fe and Tc Reduction and Oxidation in FRC Sediment

International Nuclear Information System (INIS)

John M, Zachara; James K, Fredrickson; Ravi K, Kukkadapu; Steven C, Smith; David W, Kennedy

2004-01-01

The objectives are: (1) To rigorously characterize the distribution of Fe(II) and Fe(III) in FRC sediment. (2) To identify changes to Fe(II)/Fe(III) distribution and concentration resulting from DIRB activity. (3) To determine the dependence of Tc(VII) reduction rate on biogenic Fe(II) and it's forms. (4) To establish tendency of Tc(IV) and biogenic Fe(II) to oxidize and their effects on Tc immobilization. The mineralogic and chemical properties of the pristine, bioreduced, and chemically extracted FRC sediments were characterized by X-ray fluorescence (XRF), X-ray diffraction (XRD), X-ray microscopy (XRM, at the PNC-CAT beamline at APS), Moessbauer spectroscopy, and scanning and transmission electron microscopy with lattice fringe imaging. Chemical extraction included dithionite-citrate-bicarbonate (DCB), acid ammonium oxalate (AAO), and hydroxylamine hydrochloride (HAH). The FRC sediment was incubated under anoxic conditions with the facultative dissimilatory metal-reducing bacterium Shewanella putrefaciens, strain CN32 in defined aqueous solutions/media with bicarbonate and PIPES buffers for time periods exceeding 75 d. Lactate was used as the electron donor. Aqueous and sorbed Fe(II) (ferrozine assay and 0.5 N HCl extraction) and Mn(II) (ICP-MS and 10 mM CuSO 4 extraction), and pH were monitored to define the reduction progress and extent. The bioreduced materials were characterized using the abovementioned techniques. Bioreduced (pasteurized) sediment or chemically extracted/reduced sediment spiked with Fe(II) was washed with a PIPES buffer/electrolyte solution, and spiked with NaTc(VII)O 4 to yield a concentration of 20 (micro)M. The Tc(VII)-spiked samples were agitated and equilibrated at 25 C and sampled over time to assess the Tc(VII) reduction rate. Selected sediment samples containing 20 (micro)M of reduced Tc [Tc(IV)] were subjected to oxidation by: (1) successive headspace replacements of air, and (2) open system equilibration with air. Removed aqueous

Systems of Rb2I2-CdI2-PbI2 and Cs2I2-CdI2-PbI2

International Nuclear Information System (INIS)

Volchanskaya, V.V.; Il'yasov, I.I.

1979-01-01

The Rb 2 I 2 -CdI 2 -PbI 2 and Cs 2 I 2 -CdI 2 -PbI 2 triple systems have been studied, using the visual-polythermal method. The liquidus of the systems researched consists of the components and compounds crystallization fields: 2RbIxCdI 2 , 2RbIxRbI 2 , RbIxPbI 2 and 2CsIxCdI 2 , 4CsIxPbI 2 , CsIxPbI 2 , respectively. The crystallization fields converge in four non-variant points at 360, 280, 205 and 192 deg C in the Rb 2 I 2 -CdI 2 -PbI 2 system and at 375, 368, 208 and 190 deg C in the CsI 2 -CdI 2 -PbI 2 system

Interlaminar Fracture Toughness of CFRP Laminates Incorporating Multi-Walled Carbon Nanotubes

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Elisa Borowski

2015-06-01

Full Text Available Carbon fiber reinforced polymer (CFRP laminates exhibit limited fracture toughness due to characteristic interlaminar fiber-matrix cracking and delamination. In this article, we demonstrate that the fracture toughness of CFRP laminates can be improved by the addition of multi-walled carbon nanotubes (MWCNTs. Experimental investigations and numerical modeling were performed to determine the effects of using MWCNTs in CFRP laminates. The CFRP specimens were produced using an epoxy nanocomposite matrix reinforced with carboxyl functionalized multi-walled carbon nanotubes (COOH–MWCNTs. Four MWCNTs contents of 0.0%, 0.5%, 1.0%, and 1.5% per weight of the epoxy resin/hardener mixture were examined. Double cantilever beam (DCB tests were performed to determine the mode I interlaminar fracture toughness of the unidirectional CFRP composites. This composite material property was quantified using the critical energy release rate, GIC. The experimental results show a 25%, 20%, and 17% increase in the maximum interlaminar fracture toughness of the CFRP composites with the addition of 0.5, 1.0, and 1.5 wt% MWCNTs, respectively. Microstructural investigations using Fourier transform infrared (FTIR spectroscopy and X-ray photoelectron spectroscopy (XPS verify that chemical reactions took place between the COOH–MWCNTs and the epoxy resin, supporting the improvements experimentally observed in the interlaminar fracture toughness of the CFRP specimens containing MWCNTs. Finite element (FE simulations show good agreement with the experimental results and confirm the significant effect of MWCNTs on the interlaminar fracture toughness of CFRP.

A finite element framework for multiscale/multiphysics analysis of structures with complex microstructures

Science.gov (United States)

Varghese, Julian

This research work has contributed in various ways to help develop a better understanding of textile composites and materials with complex microstructures in general. An instrumental part of this work was the development of an object-oriented framework that made it convenient to perform multiscale/multiphysics analyses of advanced materials with complex microstructures such as textile composites. In addition to the studies conducted in this work, this framework lays the groundwork for continued research of these materials. This framework enabled a detailed multiscale stress analysis of a woven DCB specimen that revealed the effect of the complex microstructure on the stress and strain energy release rate distribution along the crack front. In addition to implementing an oxidation model, the framework was also used to implement strategies that expedited the simulation of oxidation in textile composites so that it would take only a few hours. The simulation showed that the tow architecture played a significant role in the oxidation behavior in textile composites. Finally, a coupled diffusion/oxidation and damage progression analysis was implemented that was used to study the mechanical behavior of textile composites under mechanical loading as well as oxidation. A parametric study was performed to determine the effect of material properties and the number of plies in the laminate on its mechanical behavior. The analyses indicated a significant effect of the tow architecture and other parameters on the damage progression in the laminates.

Effects of cold working ratio and stress intensity factor on intergranular stress corrosion cracking susceptibility of non-sensitized austenitic stainless steels in simulated BWR and PWR primary water

International Nuclear Information System (INIS)

Yaguchi, Seiji; Yonezawa, Toshio

2012-01-01

To evaluate the effects of cold working ratio, stress intensity factor and water chemistry on an IGSCC susceptibility of non-sensitized austenitic stainless steel, constant displacement DCB specimens were applied to SCC tests in simulated BWR and PWR primary water for the three types of austenitic stainless steels, Types 316L, 347 and 321. IGSCC was observed on the test specimens in simulated BWR and PWR primary water. The observed IGSCC was categorized into the following two types. The one is that the IGSCC observed on the same plane of the pre-fatigue crack plane, and the other is that the IGSCC observed on a plane perpendicular to the pre-fatigue crack plane. The later IGSCC fractured plane is parallel to the rolling plane of a cold rolled material. Two types of IGSCC fractured planes were changed according to the combination of the testing conditions (cold working ratio, stress intensity factor and simulated water). It seems to suggest that the most susceptible plane due to fabrication process of materials might play a significant role of IGSCC for non-sensitized cold worked austenitic stainless steels, especially, in simulated PWR primary water. Based upon evaluating on the reference crack growth rate (R-CGR) of the test specimens, the R-CGR seems to be mainly affected by cold working ratio. In case of simulated PWR primary water, it seems that the effect of metallurgical aspects dominates IGSCC susceptibility. (author)

Interfacial characterization of flexible hybrid electronics

Science.gov (United States)

Najafian, Sara; Amirkhizi, Alireza V.; Stapleton, Scott

2018-03-01

Flexible Hybrid Electronics (FHEs) are the new generation of electronics combining flexible plastic film substrates with electronic devices. Besides the electrical features, design improvements of FHEs depend on the prediction of their mechanical and failure behavior. Debonding of electronic components from the flexible substrate is one of the most common and critical failures of these devices, therefore, the experimental determination of material and interface properties is of great importance in the prediction of failure mechanisms. Traditional interface characterization involves isolated shear and normal mode tests such as the double cantilever beam (DCB) and end notch flexure (ENF) tests. However, due to the thin, flexible nature of the materials and manufacturing restrictions, tests mirroring traditional interface characterization experiments may not always be possible. The ideal goal of this research is to design experiments such that each mode of fracture is isolated. However, due to the complex nonlinear nature of the response and small geometries of FHEs, design of the proper tests to characterize the interface properties can be significantly time and cost consuming. Hence numerical modeling has been implemented to design these novel characterization experiments. This research involves loading case and specimen geometry parametric studies using numerical modeling to design future experiments where either shear or normal fracture modes are dominant. These virtual experiments will provide a foundation for designing similar tests for many different types of flexible electronics and predicting the failure mechanism independent of the specific FHE materials.

Investigation of the Na2(H2PO2)2 - Ba(H2PO2)2 - H2O Water-Salt Ternary System at Room Temperature

OpenAIRE

Erge, Hasan; Turan, Hakan; Kul, Ali Riza

2016-01-01

Objective: In this study, the solubility, density, conductivity and phase equilibria of the Na2(H2PO2)2-Ba(H2PO2)2-H2O ternary system located in the structure of the Na+, Ba2+, (H2PO2)-//H2O quaternary reciprocal water-salt system were investigated using physicochemical analysis methods. Material and Methods: Riedel-de Haen and Merck salts were used to investigate the solubility and phase equilibria of the Na2(H2PO2)2 -Ba(H2PO2)2-H2O ternary water–salt system at room temperature Res...

Does dinitrogen hydrogenation follow different mechanisms for [(eta5-C5Me4H)2Zr]2(mu2,eta2,eta2-N2) and {[PhP(CH2SiMe2NSiMe2CH2)PPh]Zr}2(mu2,eta2,eta2-N2) complexes? A computational study.

Science.gov (United States)

Bobadova-Parvanova, Petia; Wang, Qingfang; Quinonero-Santiago, David; Morokuma, Keiji; Musaev, Djamaladdin G

2006-09-06

The mechanisms of dinitrogen hydrogenation by two different complexes--[(eta(5)-C(5)Me(4)H)(2)Zr](2)(mu(2),eta(2),eta(2)-N(2)), synthesized by Chirik and co-workers [Nature 2004, 427, 527], and {[P(2)N(2)]Zr}(2)(mu(2),eta(2),eta(2)-N(2)), where P(2)N(2) = PhP(CH(2)SiMe(2)NSiMe(2)CH(2))(2)PPh, synthesized by Fryzuk and co-workers [Science 1997, 275, 1445]--are compared with density functional theory calculations. The former complex is experimentally known to be capable of adding more than one H(2) molecule to the side-on coordinated N(2) molecule, while the latter does not add more than one H(2). We have shown that the observed difference in the reactivity of these dizirconium complexes is caused by the fact that the former ligand environment is more rigid than the latter. As a result, the addition of the first H(2) molecule leads to two different products: a non-H-bridged intermediate for the Chirik-type complex and a H-bridged intermediate for the Fryzuk-type complex. The non-H-bridged intermediate requires a smaller energy barrier for the second H(2) addition than the H-bridged intermediate. We have also examined the effect of different numbers of methyl substituents in [(eta(5)-C(5)Me(n)H(5)(-)(n))(2)Zr](2)(mu(2),eta(2),eta(2)-N(2)) for n = 0, 4, and 5 (n = 5 is hypothetical) and [(eta(5)-C(5)H(2)-1,2,4-Me(3))(eta(5)-C(5)Me(5))(2)Zr](2)(mu(2),eta(2),eta(2)-N(2)) and have shown that all complexes of this type would follow a similar H(2) addition mechanism. We have also performed an extensive analysis on the factors (side-on coordination of N(2) to two Zr centers, availability of the frontier orbitals with appropriate symmetry, and inflexibility of the catalyst ligand environment) that are required for successful hydrogenation of the coordinated dinitrogen.

Syntheses of 4-aminobutanoic acid-2,2-/sup 2/H/sub 2/ and -4,4-/sup 2/H/sub 2/ and progabide-2,2-/sup 2/H/sub 2/ and -4,4-/sup 2/H/sub 2/

Energy Technology Data Exchange (ETDEWEB)

Davis, B.

1987-10-01

4-Aminobutanoic acid-2,2-/sup 2/H/sub 2/ and -4,4-/sup 2/H/sub 2/ were synthesized in high yield with high deuterium incorporation, and then converted into the corresponding deuterium-labelled anti-convulsant drug, progabide, by means of a transimination reaction.

(Solid + liquid) phase equilibria of (Ca(H2PO2)2 + CaCl2 + H2O) and (Ca(H2PO2)2 + NaH2PO2 + H2O) ternary systems at T = 323.15 K

International Nuclear Information System (INIS)

Cao, Hong-yu; Zhou, Huan; Bai, Xiao-qin; Ma, Ruo-xin; Tan, Li-na; Wang, Jun-min

2016-01-01

Graphical abstract: Solubility diagram of the (Ca(H 2 PO 2 ) 2 + NaH 2 PO 2 + H 2 O) system at T = (323.15 and 298.15) K. - Highlights: • Phase diagrams of Ca 2+ -H 2 PO 2 − -Cl − -H 2 O, Ca 2+ -Na + -H 2 PO 2 − -H 2 O at 323.15 K were obtained. • Incompatible double salt of NaCa(H 2 PO 2 ) 3 in Ca 2+ -Na + -H 2 PO 2 − -H 2 O system was determined. • Density diagram of the corresponding liquid were simultaneously measured. - Abstract: Calcium hypophosphite has been widely used as an anti-corrosive agent, flame retardant, fertilizer, assistant for Ni electroless plating, and animal nutritional supplement. High purity calcium hypophosphite can be synthesized via the replacement reaction of sodium hypophosphite and calcium chloride. In this work, the (solid + liquid) phase equilibria of (Ca(H 2 PO 2 ) 2 + CaCl 2 + H 2 O) and (Ca(H 2 PO 2 ) 2 + NaH 2 PO 2 + H 2 O) ternary systems at T = 323.15 K were studied experimentally via the classical isothermal solubility equilibrium method, and the phase diagrams for these two systems were obtained. It was found that two solid salts of CaCl 2 ·2H 2 O and Ca(H 2 PO 2 ) 2 exist in the (Ca(H 2 PO 2 ) 2 + CaCl 2 + H 2 O) system, and three salts of Ca(H 2 PO 2 ) 2 , NaH 2 PO 2 ·H 2 O and one incompatible double salt, NaCa(H 2 PO 2 ) 3 occur in the (Ca(H 2 PO 2 ) 2 + NaH 2 PO 2 + H 2 O) system.

Synthesis and structure of [(NH2)2CSSC(NH2)2]2[OsBr6]Br2 . 3H2O

International Nuclear Information System (INIS)

Rudnitskaya, O. V.; Kultyshkina, E. K.; Stash, A. I.; Glukhova, A. A.; Venskovskii, N. U.

2008-01-01

The complex [(NH 2 ) 2 CSSC(NH 2 ) 2 ] 2 [OsBr 6 ]Br 2 . 3H 2 O is synthesized by the reaction of K 2 OsBr 6 with thiocarbamide in concentrated HBr and characterized using electronic absorption and IR absorption spectroscopy. Its crystal structure is determined by X-ray diffraction. The crystals are orthorhombic, a = 11.730(2) A, b = 14.052(3) A, c = 16.994(3) A, space group Cmcm, and Z = 4. The [OsBr 6 ] 2- anionic complex has an octahedral structure. The Os-Br distances fall in the range 2.483-2.490 A. The α,α'-dithiobisformamidinium cation is a product of the oxidation of thiocarbamide. The S-S and C-S distances are 2.016 and 1.784 A, respectively. The H 2 O molecules, Br - ions, and NH 2 groups of the cation are linked by hydrogen bonds.

Hydrothermal synthesis and crystal structures of new uranyl oxalate hydroxides: α- and β-[(UO2)2(C2O4)(OH)2(H2O)2] and [(UO2)2(C2O4)(OH)2(H2O)2].H2O

International Nuclear Information System (INIS)

Duvieubourg, Laurence; Nowogrocki, Guy; Abraham, Francis; Grandjean, Stephane

2005-01-01

Two modifications of the new uranyl oxalate hydroxide dihydrate [UO 2 ) 2 (C 2 O 4 )(OH) 2 (H 2 O) 2 ] (1 and 2) and one form of the new uranyl oxalate hydroxide trihydrate [(UO 2 ) 2 (C 2 O 4 )(OH) 2 (H 2 O) 2 ].H 2 O (3) were synthesized by hydrothermal methods and their structures determined from single-crystal X-ray diffraction data. The crystal structures were refined by full-matrix least-squares methods to agreement indices R(wR)=0.0372(0.0842) and 0.0267(0.0671) calculated for 1096 and 1167 unique observed reflections (I>2σ(I)), for α (1) and β (2) forms, respectively and to R(wR)=0.0301(0.0737) calculated for 2471 unique observed reflections (I>2σ(I)), for 3. The α-form of the dihydrate is triclinic, space group P1-bar , Z=1, a=6.097(2), b=5.548(2), c=7.806(3)A, α=89.353(5), β=94.387(5), γ=97.646(5) o , V=260.88(15)A 3 , β-form is monoclinic, space group C2/c, Z=4, a=12.180(3), b=8.223(2), c=10.777(3)A, β=95.817(4), V=1073.8(5)A 3 . The trihydrate is monoclinic, space group P2 1 /c, Z=4, a=5.5095(12), b=15.195(3), c=13.398(3)A, β=93.927(3), V=1119.0(4)A 3 . In the three structures, the coordination of uranium atom is a pentagonal bipyramid composed of dioxo UO 2 2+ cation perpendicular to five equatorial oxygen atoms belonging to one bidentate oxalate ion, one water molecule and two hydroxyl ions in trans configuration in 2 and in cis configuration in 1 and 3. The UO 7 polyhedra are linked through hydroxyl oxygen atoms to form different structural building units, dimers [U 2 O 10 ] obtained by edge-sharing in 1, chains [UO 6 ] ∼ and tetramers [U 4 O 26 ] built by corner-sharing in 2 and 3, respectively. These units are further connected by oxalate entities that act as bis-bidentate to form one-dimensional chains in 1 and bi-dimensional network in 2 and 3. These chains or layers are connected in frameworks by hydrogen-bond arrays

Temporal pole signal abnormality on MR imaging in temporal lobe epilepsy with hippocampal sclerosis: a fluid-attenuated inversion-recovery study; Anormalidade de sinal na imagem por RM do polo temporal na epilepsia do lobo temporal com esclerose hipocampal: um estudo pela sequencia inversao recuperacao com supressao da agua livre (FLAIR)

Energy Technology Data Exchange (ETDEWEB)

Carrete Junior, Henrique; Abdala, Nitamar; Szjenfeld, Jacob; Nogueira, Roberto Gomes [Universidade Federal de Sao Paulo (UNIFESP-EPM), Sao Paulo, SP (Brazil). Dept. de Diagnostico por Imagem; Lin, Katia; Caboclo, Luis Otavio; Centeno, Ricardo Silva; Sakamoto, Americo Ceiki; Yacubian, Elza Marcia Targas [Universidade Federal de Sao Paulo (UNIFESP-EPM), Sao Paulo, SP (Brazil). Dept. de Neurologia e Neurocirurgia

2007-09-15

Objective: To determine the frequency and regional involvement of temporal pole signal abnormality (TPA) in patients with hippocampal sclerosis (HS) using fluid-attenuated inversion-recovery (FLAIR) MR imaging, and to correlate this feature with history. Method: Coronal FLAIR images of the temporal pole were assessed in 120 patients with HS and in 30 normal subjects, to evaluate gray-white matter demarcation. Results: Ninety (75%) of 120 patients had associated TPA. The HS side made difference regarding the presence of TPA, with a left side prevalence (p=0.04, {chi}{sup 2} test). The anteromedial zone of temporal pole was affected in 27 (30%) out of 90 patients. In 63 (70%) patients the lateral zone were also affected. Patients with TPA were younger at seizure onset (p=0.018), but without association with duration of epilepsy. Conclusion: Our FLAIR study show temporal pole signal abnormality in 3/4 of patients with HS, mainly seen on the anteromedial region, with a larger prevalence when the left hippocampus was involved. (author)

Bis{(E-3-[2-(hydroxyiminopropanamido]-2,2-dimethylpropan-1-aminium} bis[μ-(E-N-(3-amino-2,2-dimethylpropyl-2-(hydroxyiminopropanamido(2−]bis{[(E-N-(3-amino-2,2-dimethylpropyl-2-(hydroxyiminopropanamide]copper(II} bis((E-{3-[2-(hydroxyiminopropanamido]-2,2-dimethylpropyl}carbamate acetonitrile disolvate

Directory of Open Access Journals (Sweden)

Andrii I. Buvailo

2012-12-01

Full Text Available The reaction between copper(II nitrate and (E-N-(3-amino-2,2-dimethylpropyl-2-(hydroxyiminopropanamide led to the formation of the dinuclear centrosymmetric copper(II title complex, (C8H18N3O22[Cu2(C8H15N3O22(C8H17N3O22](C9H16N3O42·2CH3CN, in which an inversion center is located at the midpoint of the Cu2 unit in the center of the neutral [Cu2(C8H15N3O22(C8H17N3O22] complex fragment. The Cu2+ ions are connected by two N—O bridging groups [Cu...Cu separation = 4.0608 (5 Å] while the CuII ions are five-coordinated in a square-pyramidal N4O coordination environment. The complex molecule co-crystallizes with two molecules of acetonitrile, two molecules of the protonated ligand (E-3-[2-(hydroxyiminopropanamido]-2,2-dimethylpropan-1-aminium and two negatively charged (E-{3-[2-(hydroxyiminopropanamido]-2,2-dimethylpropyl}carbamate anions, which were probably formed as a result of condensation between (E-N-(3-amino-2,2-dimethylpropyl-2-(hydroxyiminopropanamide and hydrogencarbonate anions. In the crystal, the complex fragment [Cu2(C8H15N3O22(C8H17N3O22] and the ion pair C8H18N3O2+.C9H16N3O4− are connected via an extended system of hydrogen bonds.

Novel packaging for CW and QCW diode laser modules for operation with high power and duty cycles

Science.gov (United States)

Fassbender, Wilhelm; Lotz, Jens; Kissel, Heiko; Biesenbach, Jens

2018-02-01

Continuous wave (CW) and quasi-continuous wave (QCW) operated diode laser bars and arrays have found a wide range of industrial, medical, scientific, military and space applications with a broad variety in wavelength, pulse energy, pulse duration and beam quality. Recent applications require even higher power, duty cycles and power density. The heat loss will be dissipated by conductive cooling or liquid cooling close to the bars. We present the latest performance and reliability data of two novel high-brightness CW and QCW arrays of customized and mass-production modules, in compact and robust industry design for operation with high power and high duty cycles. All designs are based on single diode packages consisting of 10mm laser bars, soft or hard soldered between expansion matched submounts. The modular components cover a wide span of designs which differ basically in water/conduction (active/passive) cooled, single, linear (horizontal and vertical) arranged designs, as well as housed and unhoused modules. The different assembling technologies of active and passive cooled base plates affect the heat dissipation and therefore the reachable power at different QCW operating conditions, as well as the lifetime. As an example, a package consisting of 8 laser diodes, connected to a 28.8*13.5*7.0mm3 DCB (direct copper bonded) submount, passively or actively cooled is considered. This design is of particular interest for mobile applications seamless module to module building system, with an infinite number of laser bars at 1.7mm pitch. Using 940nm bars we can reach an optical output power per bar of 450W at 25°C base plate temperature with 10Hz, 1.2% duty cycle and 1.2ms pulse duration. As an additional example, micro channel coolers can be vertically stacked up to 50 diodes with a 1,15mm pitch. This design is suitable for all applications, demanding also compactness and light weight and high power density. Using near infrared bars and others, we can reach an optical

Gl(2/2)-oscillators and Gl(2/2)-dynamical symmetry

International Nuclear Information System (INIS)

Kamupingene, A.H.; Nguyen Anh Ky.

1991-07-01

Extending the concept of the dynamical symmetry, we identify the Lie superalgebra Gl(2/2) as a dynamical (super-)algebra of a class of non-canonical quantum systems, whose dynamical variables and quantities can be realized in terms of the Gl(2/2)-generators. In this way, a new class of harmonic oscillators is established. As a consequence of the choice of the dynamical variables the Heisenberg algebra and the Hermitian condition for the Gl(2/2)-representations are also given. (author). 12 refs

2-(2-Pyridylpyridinium (2,2′-bipyridine-κ2N,N′tetrakis(nitrato-κ2O,O′bismuthate(III

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Shu-Shen Zhang

2011-10-01

Full Text Available The structure of the title compound, (C10H9N2[Bi(NO34(C10H8N2], consists of 2-(2-pyridylpyridinium cations and anions [Bi(NO34(C10H8N2]−. The Bi3+ ion lies on the twofold axis. It is coordinated by two nitrogen atoms from one 2,2′-bipyridine ligand and eight oxygen atoms from four NO3− anions. The disordered cation is positioned at the inversion centre. The [Bi(NO34(C10H8N2]− anions and 2-(2-pyridylpyridinium cations are connected via N—H...O hydrogen bonds into chains. Moreover, these chains are further linked into a two-dimensional layered structure through π–π stacking interactions between bipyridine ligands along the c axis [centroid–centroid distance = 2.868 (4 Å].

Correlation of the octanol/water partition coefficient with clearance halftimes of intratracheally instilled aromatic hydrocarbons in rats

International Nuclear Information System (INIS)

Bond, J.A.; Baker, S.M.; Bechtold, W.E.

1985-01-01

Studies on the lung retention of polycyclic aromatic hydrocarbons (PAH) after inhalation have indicated that, in general, the PAH are rapidly cleared from the respiratory tract. Clearance of the PAH from the lungs is best described as bi-phasic, with the long-term component of the clearance curve having a half-time of greater than 24 h. The purpose of this study was to determine whether a relationship exists between the lipophilicity (as measured by the octanol/water partition coefficient, P) of various PAH and the short-term and long-term clearance half-times of PAH in rat lungs. Female F344/Crl rats were administered intratracheally 1 nmol of 14 C-labelled anthracene (AN), benz (a) anthracene (BA), 1-nitropyrene (NP), 6-nitrobenzo (a) pyrene (6-NBP), or dibenzo (c, g) carbazole (DBC). At various times after instillation rats were sacrificed and the amount of 14 C from rat lungs following instillation of the different PAH was biphasic. In all cases, greater than 85% of the initial dose instilled was cleared with a half-time of less than 1 h. The half-times for clearance of the residual 14 C (1-15% of the dose) were 26, 30, 36, 53 and 63 h for AN, NP, 6-NBP, BA and DCB, respectively. The log of the octanol-water partition coefficients for the different PAH examined ranged from 4.1 (AN) to 6.05 (DBC). Plots of the octanol/water coefficients vs. the long-term clearance half-time for the PAH indicated a linear correlation (p 2 =0.96). The results from this study indicate that the greater the lipophilicity of the PAH, the slower the long-term clearance of a small fraction (1-15%) of PAH from rat lungs. These data suggest that predictions of long-term lung clearance can be made for PAH with log octanol-water partition coefficients between 4 and 6. (author)

49 CFR 173.115 - Class 2, Divisions 2.1, 2.2, and 2.3-Definitions.

Science.gov (United States)

2010-10-01

... substances of Class 8, PG I are forbidden from transportation in an aerosol container. (7) Flammable... 2.1, 2.2, and 2.3—Definitions. (a) Division 2.1 (Flammable gas). For the purpose of this subchapter, a flammable gas (Division 2.1) means any material which is a gas at 20 °C (68 °F) or less and 101.3...

Vacina contra o vírus da influenza e mortalidade por doenças cardiovasculares na cidade de São Paulo Vacuna contra el virus de la Influenza y mortalidad por enfermedades cardiovasculares en la Ciudad de São Paulo Vaccination against the influenza virus and mortality due to cardiovascular diseases in the city of Sao Paulo

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Antonio de Padua Mansur

2009-10-01

Full Text Available FUNDAMENTO: A influência da vacinação contra o vírus da gripe na mortalidade por doenças cardiovasculares (DCV é controversa. OBJETIVO: Analisar a mortalidade por DCV antes e depois do início da vacinação contra a gripe na cidade de São Paulo. MÉTODOS: Analisou-se a mortalidade por doenças isquêmicas do coração (DIC, doenças cerebrovasculares (DCbV e por causas externas (CE na população da região metropolitana de São Paulo com idade > 60 anos, antes e depois do programa de vacinação contra a gripe. As estimativas da população e os dados de mortalidade foram, respectivamente, obtidos do Instituto Brasileiro de Geografia e Estatística (IBGE; www.ibge.gov.br e do Ministério da Saúde (www.datasus.gov.br para o período entre 1980 e 2006. O risco de morte foi ajustado pelo método direto, em que se utilizou a população padrão (mundial referente a 1960. RESULTADOS: As comparações entre as inclinações das linhas de regressão foram semelhantes para as DCbV (p = 0,931 e CE (p = 0,941, porém, para as DIC (p = 0,022, observou-se significativa redução da linha do período pós-vacina quando comparada com a linha do período pré-vacina. Mudança na tendência da mortalidade após 1996 foi significativa somente para as DIC (p = 0,022, permanecendo inalterada para as DCbV (p = 0,931 e CE (p = 0,941. CONCLUSÃO: A vacinação contra a gripe associou-se a significativa redução da mortalidade por DIC.FUNDAMENTO: La influencia de la vacunación contra el virus de la gripe en la mortalidad por enfermedades cardiovasculares (ECV es controvertida. OBJETIVO: Analizar la mortalidad por ECV antes y después del inicio de la vacunación contra la gripe en la ciudad de São Paulo. MÉTODOS: Se analizó la mortalidad por enfermedades isquémicas del corazón (EIC, enfermedades cerebrovasculares (ECbV y por causas externas (CE en la población de la región metropolitana de São Paulo con edad > 60 años, antes y después del

¿Qué modelos de enseñanza-aprendizaje adoptan los profesores de Secundaria de Matemáticas? O, cómo los profesores han seguido haciendo lo de siempre pese a la Reforma

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Aurora PLATA CASÁIS

2009-11-01

Full Text Available RESUMEN: Nuestro interés se orienta a conocer cómo los profesores entienden la enseñanza, cuáles son sus concepciones sobre las matemáticas y sobre el modo como aprenden los alumnos, cómo entienden la evaluación y cuál es la opinión que tienen sobre su propia práctica.Para la recogida de información planteamos una entrevista a 21 profesores de centros públicos de la ciudad de Santiago de Compostela.Nuestra interpretación de los datos arroja este resultado mayoritario:Concepción de las matemáticas y sus consecuencias en el programa: destaca la escasa atención que los profesores dedican a la reflexión acerca del significado de las matemáticas y su aportación específica a la formación de los estudiantes.Sobre la resolución de problemas: destaca su manifiesta contradicción, desconsideración e incluso oposición respecto a esta opción didáctica.Concepción de la enseñanza y el aprendizaje, y su práctica: destaca que «enseñar es transmitir información y que aprender es saber hacer los ejercicios».Sobre la evaluación del aprendizaje: destaca que la evaluación es sinónimo de examen y de calificación para seleccionar al estudiante (único responsable de su fracaso. Pero más allá de esto, el trabajo informa también sobre cuáles son los modelos de enseñanza-aprendizaje subyacentes.Como conclusión radical: prácticamente nada de lo que propone el DCB del MEC para la enseñanza-aprendizaje de las matemáticas en Secundaria, ha calado en las conciencias y en los usos de la mayor parte de los profesores que hemos entrevistado.ABSTRACT: Our interest is directed to know how teachers understand education, how their understanding of Maths and the way students learn are, how evaluation is understood and what the opinion about their own practice is.An interview to 21 teachers from public centres in the town of Santiago de Compostela was put forward to collect information.The results of our interpretation of the dates were as

New superhindered polydentate polyphosphine ligands P(CH2CH2P(t)Bu2)3, PhP(CH2CH2P(t)Bu2)2, P(CH2CH2CH2P(t)Bu2)3, and their ruthenium(II) chloride complexes.

Science.gov (United States)

Gilbert-Wilson, Ryan; Field, Leslie D; Bhadbhade, Mohan M

2012-03-05

The synthesis and characterization of the extremely hindered phosphine ligands, P(CH(2)CH(2)P(t)Bu(2))(3) (P(2)P(3)(tBu), 1), PhP(CH(2)CH(2)P(t)Bu(2))(2) (PhP(2)P(2)(tBu), 2), and P(CH(2)CH(2)CH(2)P(t)Bu(2))(3) (P(3)P(3)(tBu), 3) are reported, along with the synthesis and characterization of ruthenium chloro complexes RuCl(2)(P(2)P(3)(tBu)) (4), RuCl(2)(PhP(2)P(2)(tBu)) (5), and RuCl(2)(P(3)P(3)(tBu)) (6). The bulky P(2)P(3)(tBu) (1) and P(3)P(3)(tBu) (3) ligands are the most sterically encumbered PP(3)-type ligands so far synthesized, and in all cases, only three phosphorus donors are able to bind to the metal center. Complexes RuCl(2)(PhP(2)P(2)(tBu)) (5) and RuCl(2)(P(3)P(3)(tBu)) (6) were characterized by crystallography. Low temperature solution and solid state (31)P{(1)H} NMR were used to demonstrate that the structure of RuCl(2)(P(2)P(3)(tBu)) (4) is probably analogous to that of RuCl(2)(PhP(2)P(2)(tBu)) (5) which had been structurally characterized.

Actividad química de los ligandos puente difósforo y difosfenilo en los complejos binucleares (Mo2Cp2(n-PCy2) (n-K2:K2-P2)(CO)2)-y (Mo2Cp2(n-PCy2)(n-K2:K2-P2Me)(CO)2)

OpenAIRE

Lozano Rivera, Raquel

2015-01-01

El trabajo de investigación que se recoge en la presente Memoria comprende un amplio estudio de la reactividad de complejos metálicos binucleares con ligandos puente difósforo y metildifosfenilo procedentes de la activación directa del fósforo blanco. Por un lado, se ha llevado a cabo un amplio análisis del comportamiento químico de la especie aniónica [Mo2Cp2(¿-PCy2)(¿-¿2:¿2-P2)(CO)2]- frente a electrófilos de distinta naturaleza, tales como clorofosfinas y complejos metálicos generadores...

Chlorobis(2,2,2-trifluoroethoxy) and dichloro(2,2,2-trifluoroethoxy)-vanadium(III): synthesis and coordination chemistry

International Nuclear Information System (INIS)

Chadha, S.L.; Uppal, K.

1987-01-01

VCl(OCH 2 CF 3 ) 2 and VCl 2 (OCH 2 CF 3 ) have been synthesised. They form complexes with monodentate oxygen or nitrogen donor ligands. The magnetic moments for these complexes indicate antiferromagnetic interactions and their electronic spectra are consistent with octahedral coordination of V(III) involving chloride, organoxy ions and the ligands. The i.r. spectra support the alkoxy-bridged structure for these complexes in which the ligands are probably cis to each other. 1 H nmr spectrum of VCl(OCH 2 CF 3 ) 2 shows a sharp quartet suggesting a sharp exchange of terminal and bridging alkoxy groups. 19 F nmr spectra of the parent compounds also show a single sharp band. The mass spectra suggest a dimeric form for both compounds in vapour phase

Fermi surfaces of YRu2Si2 and LaRu2Si2

International Nuclear Information System (INIS)

Settai, R.; Ikezawa, H.; Toshima, H.; Takashita, M.; Ebihara, T.; Sugawara, H.; Kimura, T.; Motoki, K.; Onuki, Y.

1995-01-01

We have measured the de Haas-van Alphen effect of YRu 2 Si 2 and LaRu 2 Si 2 to clarify the Fermi surfaces and cyclotron masses. Main hole-Fermi surfaces of both compounds with a distorted ellipsoid shape are similar, occupying about half of the Brillouin zone. The small hole-Fermi surfaces with the shape of a rugby ball are three in number for LaRu 2 Si 2 , and one for YRu 2 Si 2 . An electron-Fermi surface consists of a doughnut like shape for LaRu 2 Si 2 , while a cylinder along the [001] direction and a multiply-connected shape exist for YRu 2 Si 2 . The cyclotron masses of YRu 2 Si 2 are a little larger than those of LaRu 2 Si 2 . ((orig.))

Boundary between Soil and Saprolite in Alisols in the South of Brazil

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Fabrício de Araújo Pedron

2015-06-01

Full Text Available Despite numerous studies conducted on the lower limit of soil and its contact with saprolite layers, a great deal of work is left to standardize identification and annotation of these variables in the field. In shallow soils, the appropriately noting these limits or contacts is essential for determining their behavior and potential use. The aims of this study were to identify and define the field contact and/or transition zone between soil and saprolite in profiles of an Alisol derived from fine sandstone and siltstone/claystone in subtropical southern Brazil and to subsequently validate the field observations through a multivariate analysis of laboratory analytical data. In the six Alisol profiles evaluated, the sequence of horizons found was A, Bt, C, and Cr, where C was considered part of the soil due to its pedogenetic structure, and Cr was considered saprolite due to its rock structure. The morphological properties that were determined in the field and that were different between the B and C horizons and the Cr layer were color, structure, texture, and fragments of saprolite. According to the test of means, the properties that support the inclusion of the C horizon as part of the soil are sand, clay, water-dispersible clay, silt/clay ratio, macroporosity, total porosity, resistance to penetration, cation exchange capacity, Fe extracted by DCB, Al, H+Al, and cation exchange capacity of clay. The properties that support the C horizon as a transition zone are silt, Ca, total organic C, and Fe extracted by ammonium oxalate. Discriminant analysis indicated differences among the three horizons evaluated.

Study of the solubility, viscosity and density in Na+, Zn2+/Cl− − H2O, Na+ − Zn2+ − (H2PO2)− − H2O, Na+, Cl−/(H2PO2)− − H2O, and Zn2+, Cl−/(H2PO2)− − H2O ternary systems, and in Na+, Zn2+/Cl−, (H2PO2)−//H2O reciprocal quaternary system at 273.15 K

International Nuclear Information System (INIS)

Adiguzel, Vedat; Erge, Hasan; Alisoglu, Vahit; Necefoglu, Hacali

2014-01-01

Highlights: • The physicochemical properties of ternary and one quaternary have been studied. • Reciprocal quaternary systems’ solubility and phase equilibrium have been studied. • In all systems the solid phases have been found. • It was found that Zn(H 2 PO 2 ) 2 salt contains 70% of the general crystallization field. - Abstract: The solubility and the physicochemical properties (density, viscosity) in the Na-Zn- Cl-H 2 O), (Na + Zn + H 2 PO 2 + H 2 O), (Na + Cl + H 2 PO 2 + H 2 O), and (Zn + Cl + H 2 PO 2 + H 2 O) ternaries, and in Na + , Zn 2+ /Cl − , (H 2 PO 2 ) − //H 2 O reciprocal quaternary systems at T = 273.15 K were investigated by using the isothermal method. The diagrams of ternary salts systems, (NaCl + ZnCl 2 + H 2 O), (NaCl + NaH 2 PO 2 + H 2 O), (NaH 2 PO 2 + Zn(H 2 PO 2 ) 2 + H 2 O), (ZnCl 2 + Zn(H 2 PO 2 ) 2 + H 2 O), are plotted in figures 1–4. However, whole ions of reciprocal quaternary salt systems are plotted in figure 5. Additionally, the density and viscosity values of ternary systems vs. their corresponding composition values in weight per cent are plotted in figures 6–10. At the (i) (ZnCl 2 + Zn(H 2 PO 2 ) 2 + H 2 O), (ii) (NaCl + ZnCl 2 + H 2 O), (iii) (NaCl + NaH 2 PO 2 + H 2 O), (iv) (NaH 2 PO 2 + Zn(H 2 PO 2 ) 2 + H 2 O) ternary systems the solid phase compositions have been determined as: (i) Zn(H 2 PO 2 ) 2 ⋅ H 2 O, Zn(H 2 PO 2 ) 2 , ZnCl 2 ⋅ 2H 2 O, (ii) NaCl, 2NaCl ⋅ ZnCl 2 ⋅ 2H 2 O, and ZnCl 2 ⋅ 2H 2 O, (iii) NaCl and NaH 2 PO 2 ⋅ H 2 O, (iv) Zn(H 2 PO 2 ) 2 ⋅ H 2 O and NaH 2 PO 2 ⋅ H 2 O, respectively. On the other hand reciprocal quaternary system was observed as: ZnCl 2 ⋅ 2H 2 O, 2NaCl ⋅ ZnCl 2 ⋅ 2H 2 O, Zn(H 2 PO 2 ) 2 ⋅ H 2 O, NaH 2 PO 2 ⋅ H 2 O, NaCl. According to results, the least soluble salt was Zn(H 2 PO 2 ) 2 . The crystallization field of this salt, being the largest in comparison with those of other salts, occupied 70% of the general crystallization field

1-Methoxy-3-o-tolylbicyclo[2.2.2]oct-5-ene-2,2-dicarbonitrile

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Orhan Büyükgüngör

2009-09-01

Full Text Available In the title compound, C18H18N2O, the cyclohexene and cyclohexane rings of the bicyclo[2.2.2]oct-5-ene unit adopt distorted boat conformations. In the crystal, molecules exist as C—H...N hydrogen-bonded centrosymmetric R22(14 dimers, which are further linked by C—H...π interactions.

4-Aza-1-azoniabicyclo[2.2.2]octane–2-aminobenzoate–2-aminobenzoic acid (1/1/1

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Hadi D. Arman

2011-11-01

Full Text Available A 4-aza-1-azoniabicyclo[2.2.2]octane cation, a 2-aminobenzoate anion and a neutral 2-aminobenzoic acid molecule comprise the asymmetric unit of the title compound, C6H13N2+·C7H6NO2−·C7H7NO2. An intramolecular N—H...O hydrogen bond occurs in the anion and in the neutral 2-aminobenzoic acid molecule. The cation provides a charge-assisted N—H...O hydrogen bond to the anion, and the 2-aminobenzoic acid molecule forms an O—H...N hydrogen bond to the unprotonated amino N atom in the cation. In this way, a three-component aggregate is formed. These are connected into a three-dimensional network by amino–carboxylate N—H...O hydrogen bonds. N—H...N hydrogen bonds are also observed.

Photolysis of H2O-H2O2 Mixtures: The Destruction of H2O2

Science.gov (United States)

Loeffler, M. J.; Fama, M.; Baragiola, R. A.; Carlson, R. W.

2013-01-01

We present laboratory results on the loss of H2O2 in solid H2O + H2O2 mixtures at temperatures between 21 and 145 K initiated by UV photolysis (193 nm). Using infrared spectroscopy and microbalance gravimetry, we measured the decrease of the 3.5 micrometer infrared absorption band during UV irradiation and obtained a photodestruction cross section that varies with temperature, being lowest at 70 K. We use our results, along with our previously measured H2O2 production rates via ionizing radiation and ion energy fluxes from the spacecraft to compare H2O2 creation and destruction at icy satellites by ions from their planetary magnetosphere and from solar UV photons. We conclude that, in many cases, H2O2 is not observed on icy satellite surfaces because the H2O2 photodestruction rate is much higher than the production rate via energetic particles, effectively keeping the H2O2 infrared signature at or below the noise level.

Bis(μ-biphenyl-2,2′-dicarboxylatobis[(2,2′-bipyridinecopper(II

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Zhe An

2009-04-01

Full Text Available The title compound, [Cu2(C14H8O42(C10H8N22], was obtained by solvothermal synthesis. The CuII atom is coordinated by one chelating 2,2′-bipyridine ligand and two carboxyl groups from different biphenyl-2,2′-dicarboxylate ligands, leading to a distorted octahedral environment. Each carboxylate group makes one short Cu—O bond [1.9608 (14 and 1.9701 (14 Å] and one longer Cu—O contact [2.4338 (17 and 2.5541 (17 Å] to each CuII atom. The biphenyl-2,2′-dicarboxylate ligands bridge between CuII atoms, forming a dinuclear complex around a crystallographic inversion centre.

SYNTHESIS AND STRUCTURAL CHARACTERISTICS OF BIS(CITRATEGERMANATES(IV (Hbipy2[Ge(HCit2]•2H2O AND [CuCl(bipy2]2[Ge(HCit2]•8H2O

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Inna Seifullina

2016-12-01

Full Text Available The crystalline compounds (Hbipy2[Ge(HCit2]·2H2O (1 and CuCl(bipy2]2[Ge(HCit2]·8H2O (2 (where H4Cit is citric acid, bipy is 2,2ʹ-bipyridine were obtained for the fi rst time and their structures were determined by the single-crystal X-ray diffraction method. Compounds were characterized by IR spectroscopy, thermogravimetric (TGA and elemental analyses. Both compounds are formed with complex bis(citrategermanate anion and protonated 2,2’-bipyridine or [Cu(bipy2Cl]+ as cations in compounds 1 and 2, respectively.

synthesis and structural characterization of n-(2-{[(2e)-2-(2 ...

African Journals Online (AJOL)

E.J. Research Institute of Chemistry, International Center for Chemical and Biological ... Benzamide and its analogues have various application in synthesis of ..... Symmetry codes: (i) x+3/2, y+1/2, z; (ii) −x+1/2, −y+1/2, −z; (iii) x, y−1, z.

Cryptand [2.2.2]quantitation in the synthesis of 2-[fluorine-18]fluoro-2-deoxy-d-glucose

International Nuclear Information System (INIS)

Kothari, P.J.; Ginos, J.; Finn, R.D.; Larson, S.M.; Link, J.M.; Krohn, K.A.; Garmestani, K.

1992-01-01

Most automated synthetic devices for the preparation of [ 18 F]2-fluoro-2-deoxy-D-glucose ([ 18 F]FDG) employ cryptand [2.2.2](4,7,13,16,21,24-hexaoxa-1,10-diazabicyclo(8.8.8)-hexacosane) to facilitate the 18 F displacement reaction. Lack of simple spectroscopic and/or chromatographic determinations for cryptands prompted our investigation with tritiated [2.2.2] cryptand reagent to determine the absolute concentration of this reagent throughout the synthetic procedure leading to the final formulation. The concentration of cryptand [2.2.2] in the final formulation has been determined to range from 0.39 μg/ml to 0.60 μg/ml which is well below the detection limit by a method recently reported. (author) 1 fig., 1 tab., 5 refs

Crystallization behavior of Li2O-SiO2, Na2O-SiO2 and Na2O-CaO-SiO2 glasses; Li2O-SiO2, Na2O-SiO2, Na2O-CaO-SiO2 kei glass no kessho sekishutsu kyodo

Energy Technology Data Exchange (ETDEWEB)

Tsutsumi, K.; Otake, J.; Nagasaka, T.; Hino, M. [Tohoku University, Sendai (Japan)

1998-06-01

It has been known that crystallization of mold powder is effective on the disturbance of heat transfer between mold and solidified shell in production of middle carbon steel slabs in continuous casting process. But it has not yet been made clear which composition of mold powder is the most suitable for crystallization. The crystallization behavior of Li2O-SiO2, Na2O-SiO2 and Na2O-CaO-SiO2 glasses was observed by differential thermal analysis (DTA) and hot-thermocouple methods with DTA in the present work. As a result, addition of alkaline metal and alkaline earth metal oxides to SiO2 increased the critical cooling rate for glass formation in binary system of Li2O-SiO2 and Na2O-SiO2 and Li2O-SiO2 system crystallized easier than Na2O-SiO2 system. In ternary system of Na2O-CaO-SiO2, addition of Na2O hurried the critical cooling rate at CaO/SiO2=0.93 mass ratio, but the rate was almost constant in the composition range of more than 15 mass% Na2O. The slag of CaO/SiO2=0.93 made the rate faster than the slag of CaO/SiO2=0.47 at constant content of 10mass% Na2O. 17 refs., 10 figs., 3 tabs.

Coordination polymers of scandium sulfate. Crystal structures of (H2Bipy)[Sc(H2O)(SO4)2]2·2H2O and (H2Bipy)[HSO4]2

International Nuclear Information System (INIS)

Petrosyants, S.P.; Ilyukhin, A.B.

2005-01-01

Compounds with general formula Cat x [Sc(H 2 O) z (SO 4 ) y ]·nH 2 O (Cat=NH 4 , H 2 Bipy (Bipy - 4,4'-bipyridine), HEdp (Edp - ethylene dipyridine)) identified on element analysis data and IR spectra are synthesized. X-ray diffraction analysis of (H 2 Bipy)[Sc(H 2 O)(SO 4 ) 2 ] 2 ·2H 2 O shows that in structure of the compound chains of ScO 6 octahedron and SO 4 tetrahedrons are joined in bands by tridentate coordination of sulfate ions. Bands form skeleton in endless emptiness of which there are H 2 Bipy 2+ cations [ru

Variability in environmental impacts of Brazilian soybean according to crop production and transport scenarios.

Science.gov (United States)

da Silva, Vamilson Prudêncio; van der Werf, Hayo M G; Spies, Airton; Soares, Sebastião Roberto

2010-09-01

Soybean production and its supply chain are highly dependent on inputs such as land, fertilizer, fuel, machines, pesticides and electricity. The expansion of this crop in Brazil in recent decades has generated concerns about its environmental impacts. To assess these impacts, two representative chains supplying soybeans to Europe were identified: Center West (CW) and Southern (SO) Brazil. Each supply chain was analyzed using Life Cycle Assessment methodology. We considered different levels of use of chemical and organic fertilizers, pesticides and machinery, different distances for transportation of inputs and different yield levels. Because transportation contributed strongly to environmental impacts, a detailed study was performed to identify the routes used to transport soybeans to seaports. Additionally, we considered different levels of land occupation and land transformation to represent the impact of deforestation in the CW region. Environmental impacts were calculated for 1000 kg of soybean up to and including the delivery to Europe at the seaport in Rotterdam, at 13% humidity. Overall results showed that the impacts are greater for CW than for SO for all impact categories studied, including acidification (7.7 and 5.3 kg SO(2) eq., respectively), climate change (959 and 510 kg CO(2) eq.), cumulative energy demand (12,634 and 6,999 MJ) and terrestrial ecotoxicity (4.9 and 3.1 kg 1,4-DCB eq.), except eutrophication and land occupation. The same trend was observed for the crop-production stage. Efforts to reduce chemical fertilizers and diesel consumption can reduce CO(2) emissions. Although deforestation for crop production has decreased in recent years, the contribution of deforestation to climate change and cumulative energy demand remains significant. In the CW scenario deforestation contributed 29% to climate change and 20% to cumulative energy demand. Results also showed that although there are different transportation options in Brazil, the current

Excitation mechanisms of 2s1/2-2p3/2 and 2p1/2-2p3/2 transitions in U82+ through U89+

International Nuclear Information System (INIS)

Decaux, V.; Beiersdorfer, P.; Osterheld, A.

1994-01-01

A model based on detailed calculations of the electron-impact excitation of n = 2 electrons in the Li- to Ne-like uranium ions was developed to interpret and explain measurements on EBIT (Electron Beam Ion Trap). While only considering the direct excitation process provided a good model for the electric dipole (El) transitions, it was necessary for the magnetic dipole (Ml) spectrum to include various additional excitation processes in the model. In particular, the model was expanded to include electron-impact excitation of n = 3 levels followed by radiative cascades. Moreover, excitation by the ionization of 2s 1/2 , 2p 1/2 , and 2p 3/2 electrons and by radiative capture of beam electrons into excited levels was added. The new model demonstrates that the dipole-forbidden lines are almost exclusively produced by indirect excitation processes

Selective fluorescence quenching of 2,3-diazabicyclo[2.2.2]oct-2-ene by nucleotides.

Science.gov (United States)

Marquez, Cesar; Pischel, Uwe; Nau, Werner M

2003-10-16

[reaction: see text] The fluorescence quenching of 2,3-diazabicyclo[2.2.2]oct-2-ene (DBO) by nucleotides has been studied. The quenching mechanism was analyzed on the basis of deuterium isotope effects, tendencies for exciplex formation, and the quenching efficiency in the presence of a molecular container (cucurbit[7]uril). Exciplex-induced quenching appears to prevail for adenosine, cytidine, and uridine, while hydrogen abstraction becomes competitive for thymidine and guanosine. Compared to other fluorescent probes, DBO responds very selectively to the type of nucleotide.

PODAAC-OSCT2-L2BV2

Data.gov (United States)

National Aeronautics and Space Administration — This dataset consists of the version 2 Level 2B science-quality ocean surface wind vector retrievals from the Oceansat-2 scatterometer (OSCAT), which was designed...

Synthesis, Structure, Bonding, and Reactivity of Metal Complexes Comprising Diborane(4) and Diborene(2): [{Cp*Mo(CO)2 }2 {μ-η2 :η2 -B2 H4 }] and [{Cp*M(CO)2 }2 B2 H2 M(CO)4 ], M=Mo,W.

Science.gov (United States)

Mondal, Bijan; Bag, Ranjit; Ghorai, Sagar; Bakthavachalam, K; Jemmis, Eluvathingal D; Ghosh, Sundargopal

2018-04-26

The reaction of [(Cp*Mo) 2 (μ-Cl) 2 B 2 H 6 ] (1) with CO at room temperature led to the formation of the highly fluxional species [{Cp*Mo(CO) 2 } 2 {μ-η 2 :η 2 -B 2 H 4 }] (2). Compound 2, to the best of our knowledge, is the first example of a bimetallic diborane(4) conforming to a singly bridged C s structure. Theoretical studies show that 2 mimics the Cotton dimolybdenum-alkyne complex [{CpMo(CO) 2 } 2 C 2 H 2 ]. In an attempt to replace two hydrogen atoms of diborane(4) in 2 with a 2e [W(CO) 4 ] fragment, [{Cp*Mo(CO) 2 } 2 B 2 H 2 W(CO) 4 ] (3) was isolated upon treatment with [W(CO) 5 ⋅thf]. Compound 3 shows the intriguing presence of [B 2 H 2 ] with a short B-B length of 1.624(4) Å. We isolated the tungsten analogues of 3, [{Cp*W(CO) 2 } 2 B 2 H 2 W(CO) 4 ] (4) and [{Cp*W(CO) 2 } 2 B 2 H 2 Mo(CO) 4 ] (5), which provided direct proof of the existence of the tungsten analogue of 2. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Structures of nitrato-(2-hydroxybenzaldehydo) (2,2 Prime -bipyridyl)copper and nitrato-(2-hydroxy-5-nitrobenzaldehydo)(2,2 Prime -bipyridyl)copper

Energy Technology Data Exchange (ETDEWEB)

Chumakov, Yu. M. [Academy of Sciences of Moldova, Institute of Applied Physics (Moldova, Republic of); Paladi, L. G. [Moldova State University (Moldova, Republic of); Antosyak, B. Ya.; Simonov, Yu. A. [Academy of Sciences of Moldova, Institute of Applied Physics (Moldova, Republic of); Tsapkov, V. I., E-mail: vtsapkov@gmail.com [Moldova State University (Moldova, Republic of); Bocelli, G. [Institute of Materials for Electronics and Magnetism (Italy); Gulea, A. P. [Moldova State University (Moldova, Republic of); Ginju, D. [Alexandru Ioan Cuza University of Iasi (Romania); Palomares-Sanchez, S. A. [Autonomous University of San Luis Potosi (Mexico)

2011-03-15

Nitrato-(2-hydroxy-5-nitrobenzaldehydo)(2,2 Prime -bipyridyl)copper (I) and nitrato-(2-hydroxybenzaldehydo)(2,2 Prime -bipyridyl)copper (II) were synthesized and characterized by X-ray diffraction. The coordination polyhedron of the central copper atom in complex I can be described as a distorted tetragonal pyramid whose base is formed by the phenol and carbonyl oxygen atoms of the monodeprotonated 2-hydroxy-5nitrobenzaldehyde molecule and the nitrogen atoms of the 2,2 Prime -bipyridyl ligand and whose apex is occupied by the oxygen atom of the nitrato group. In the crystal structure, complexes I are linked by the acido ligands and the NO{sub 2} groups of the aldehyde molecule into infinite chains. In complex II, the central copper atom is coordinated by 2-hydroxybenzaldehyde, 2,2 Prime -bipyridyl, and the nitrato group, resulting in the formation of centrosymmetric dimers. The coordination polyhedron of the central copper atom can be described as a bipyramid (4 + 1 + 1) with the same base as in complex I. The axial vertices of the bipyramid are occupied by the oxygen atom of the nitrato group and the bridging phenol oxygen atom of the adjacent complex related to the initial complex by a center of symmetry. In the crystal structure, complexes II are hydrogen bonded into infinite chains.

Micropore Formation of [Zn2(Oxac) (Taz)2]·(H2O)2.5 via CO2 Adsorption.

Science.gov (United States)

Zubir, Moondra; Hamasaki, Atom; Iiyama, Taku; Ohta, Akira; Ohki, Hiroshi; Ozeki, Sumio

2017-01-24

As-synthesized [Zn 2 (Oxac) (Taz) 2 ]·(H 2 O) 2.5 , referred to as ZOTW 2.5 , was prepared from aqueous methanol solutions of Zn 5 (CO 3 ) 2 (OH) 6 and two kinds of ligands of 1,2,4-triazole (Taz) and oxalic acid (Oxac) at 453 K for 12 h. The crystal structure was determined by the Rietveld method. As-synthesized ZOTW 2.5 was pretreated at 383 K and 1 mPa for t pt h, ZOTW x (t pt h). ZOTW x (≥3h) showed a type I adsorption isotherm for N 2 at 77 K having a saturation amount (V s ) of 180 mg/g, but that pretreated shortly showed only 1/10 in V s . CO 2 was adsorbed at 303 K in sigmoid on nonporous ZOTW x (≤2h) and in Langmuir-type on ZOTW x (≥3h) to reach the adsorption amount of 120 mg/g at 700 Torr. N 2 adsorption on ZOTW x (≤2h)deCO 2 , degassed after CO 2 adsorption on ZOTW x (≤2h), was promoted 5-fold from 180 mg/g on ZOTW x (t pt h) and ZOTW x (≥3h)deCO 2 up to ca. 1000 mg/g. The interaction of CO 2 and H 2 O molecules in micropores may lead to a new route for micropore formation.

Synthesis and crystal structures of new complexes of Np(V) glycolate with 2,2'-bipyridine, [NpO2(C10H8N2)(OOC2H2OH)].1.5H2O and [NpO2(C10H8N2)(OOC2H2OH)].2.5H2O

International Nuclear Information System (INIS)

Charushnikova, I.A.; Krot, N.N.; Starikova, Z.A.

2009-01-01

Single crystals were prepared, and the structures of two complexes of Np(V) glycolate with 2,2'-bipyridine of the compositions [NpO 2 (C 10 H 8 N 2 )(OOC 2 H 2 OH)].1.5H 2 O (I) and [NpO 2 (C 10 H 8 N 2 )(OOC 2 H 2 OH)]2.5H 2 O (II) were studied. The structures of the compounds are based on neptunyl-glycolate chains in which the glycolate anion manifests its complexation ability in different manner. In structure I, the bidentate-bridging anion links the adjacent NpO 2 - cations through the oxygen atoms of the carboxylate group. The neptunyl-glycolate chains of I exhibits the mutual coordination of the NpO 2 - cations acting toward each other simultaneously as ligands and coordinating centers. In compound II, the glycolate anion is bidentately coordinated to one neptunium atom to form a planar five-membered metallocycle [NpOCCO]. The O atom external with respect to the metallocycle is in the coordination environment of the adjacent neptunyl. The nitrogen-containing molecular ligand Bipy is included into the coordination environment of Np. The coordination polyhedron of the Np atoms in both structures is a pentagonal bipyramid in which the average Np-N bond length is 2.666 Aa (I) and 2.596 Aa (II). (orig.)

Enatioselective[2+2+2] Cycloaddition as A Synthetic Tool

Institute of Scientific and Technical Information of China (English)

T.Shibata; S.Yoshida; M.Otsuka; Y.Arai; K.Endo

2007-01-01

1 Results Transition metal-catalyzed [2+2+2] cycloaddition is one of the most efficient protocols for the construction of six-membered ring system.Our group has comprehensively studied various types of highly enantioselective [2+2+2] cycloaddition for the synthesis of chiral cycloadducts; we already reported an iridium-catalyzed intermolecular [2+2+2] cycloaddition between α,ω-diynes,having various tethers and substituents on the alkyne termini,and monoalkynes,possessing oxygen or/and nitrogen functiona...

Solvent extraction of Ca2+, Ba2+, Cu2+, Zn2+, Cd2+, Pb2+, UO22+, Mn2+, Co2+ and Ni2+ into nitrobenzene using strontium dicarbol-lylcobaltate and tetra-tert-butyl p-tert-butylcalix[4]arene tetraacetate

Directory of Open Access Journals (Sweden)

E. MAKRLÍK

2008-12-01

Full Text Available The exchange extraction constants corresponding to the general equilibrium M2+(aq + SrL2+(nb D ML2+ (nb + Sr2+ (aq occurring in the two-phase water–nitrobenzene system (M2+ = Ca2+, Ba2+, Cu2+, Zn2+, Cd2+, Pb2+, UO22+, Mn2+, Co2+ or Ni2+; L = tetra-tert-butyl p-tert-butylcalix[4]arene tetraacetate; aq = aqueous phase; nb = nitrobenzene phase were evaluated from extraction experiments and -activity measurements. Furthermore, the stability constants of the ML2+ complexes in water saturated nitrobenzene were calculated; they were found to increase in the cation order Ba2+ < Mn2+ < Pb2+, Co2+ < Cu2+, Zn2+ < Cd2+, Ni2+ < UO22+ < Ca2+.

Reactions of R(2)P-P(SiMe(3))Li with [(R'(3)P)(2)PtCl(2)]. A general and efficient entry to phosphanylphosphinidene complexes of platinum. Syntheses and structures of [(eta(2)-P=(i)Pr(2))Pt(p-Tol(3)P)(2)], [(eta(2)-P=(t)Bu(2))Pt(p-Tol(3)P)(2)], [{eta(2)-P=(N(i)Pr(2))(2)}Pt(p-Tol(3)P)(2)] and [{(Et(2)PhP)(2)Pt}(2)P(2)].

Science.gov (United States)

Domańska-Babul, Wioleta; Chojnacki, Jaroslaw; Matern, Eberhard; Pikies, Jerzy

2009-01-07

The reactions of lithium derivatives of diphosphanes R(2)P-P(SiMe(3))Li (R = (t)Bu, (i)Pr, Et(2)N and (i)Pr(2)N) with [(R'(3)P)(2)PtCl(2)] (R'(3)P = Et(3)P, Et(2)PhP, EtPh(2)P and p-Tol(3)P) proceed in a facile manner to afford side-on bonded phosphanylphosphinidene complexes of platinum [(eta(2)-P=R(2))Pt(PR'(3))(2)]. The related reactions of Ph(2)P-P(SiMe(3))Li with [(R'(3)P)(2)PtCl(2)] did not yield [(eta(2)-P=PPh(2))Pt(PR'(3))(2)] and resulted mainly in the formation of [{(R'(3)P)(2)Pt}(2)P(2)], Ph(2)P-PLi-PPh(2), (Me(3)Si)(2)PLi and (Me(3)Si)(3)P. Crystallographic data are reported for the compounds [(eta(2)-P=R(2))Pt(p-Tol(3)P)(2)] (R = (t)Bu, (i)Pr, ((i)Pr(2)N)(2)P) and for [{(Et(2)PhP)(2)Pt}(2)P(2)].

Study of Paramagnetic Monohydrates MeSO4.1H2O (Me = Mn2+, Co2+, Fe2+, Ni2+, Cu2+

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Jelšovská Kamila

2000-09-01

Full Text Available Nuclear magnetic resonance (NMR of protons of crystrallization water in isomorphous paramagnetic monohydrates MeSO4.1H2O with Me = Mn2+ , Co2+ , Fe2+ , Ni2+ , Cu2+ is studied in the present paper. Several physically important parameters characterizing the studied substances were derived from the NMR spectra. In this paper we analysed the dependences of the NMR second moment M2 on the magnitude of the external magnetic field induction Br and the temperature. The proton NMR spectra in paramagnetic hydrates have an asymmetric form caused by the anisotropy of the local magnetic field acting on resonating nuclei and their second moments, M2, depend linearly on the square of the external magnetic field Br. The parameters M20 (the part of the second moment M2 which corresponds to the nuclear dipole-dipole interactions and á which characterize nuclear dipole-dipole interactions of protons and paramagnetic ions, respectively, are derived from experimentally obtained dependences of M2 vs Br2. The measurements were performed at the room temperature. Calculations were realized using the approximation where two nearest neighbour ions Me2+ to each water molecule are considered. The temperature dependence of the second moment, which was realised in the temperature range 123-313 K, was more informative than the field one. Besides the individual dependences M2(T measured at fr1 and fr2 we analysed the temperature dependence of the difference ∆M2(T. Beside the second moment M20 the Curie-Weiss constant è and the magnetic moment µi of paramagnetic ions were determined from the temperature dependences. The parameters è and M20 were determined directly from the experimental data. Some knowledge on the crystalline structure for the studied substance was required for the calculation of the magnetic moment µi. By means of the classification of substances according to the Curie-Weiss parameter, the negative value of the temperature parameter è for all studied

Raman spectroscopy of DNA-metal complexes. II. The thermal denaturation of DNA in the presence of Sr2+, Ba2+, Mg2+, Ca2+, Mn2+, Co2+, Ni2+, and Cd2+.

OpenAIRE

Duguid, J G; Bloomfield, V A; Benevides, J M; Thomas, G J

1995-01-01

Differential scanning calorimetry, laser Raman spectroscopy, optical densitometry, and pH potentiometry have been used to investigate DNA melting profiles in the presence of the chloride salts of Ba2+, Sr2+, Mg2+, Ca2+, Mn2+, Co2+, Ni2+, and Cd2+. Metal-DNA interactions have been observed for the molar ratio [M2+]/[PO2-] = 0.6 in aqueous solutions containing 5% by weight of 160 bp mononucleosomal calf thymus DNA. All of the alkaline earth metals, plus Mn2+, elevate the melting temperature of ...

Influence of basis-set size on the X Σ 1 /2 +2 , A Π 1 /2 2 , A Π 3 /2 2 , and B Σ 1 /2 +2 potential-energy curves, A Π 3 /2 2 vibrational energies, and D1 and D2 line shapes of Rb+He

Science.gov (United States)

Blank, L. Aaron; Sharma, Amit R.; Weeks, David E.

2018-03-01

The X Σ 1 /2 +2 , A Π 1 /2 2 , A Π 3 /2 2 , and B2Σ1/2 + potential-energy curves for Rb+He are computed at the spin-orbit multireference configuration interaction level of theory using a hierarchy of Gaussian basis sets at the double-zeta (DZ), triple-zeta (TZ), and quadruple-zeta (QZ) levels of valence quality. Counterpoise and Davidson-Silver corrections are employed to remove basis-set superposition error and ameliorate size-consistency error. An extrapolation is performed to obtain a final set of potential-energy curves in the complete basis-set (CBS) limit. This yields four sets of systematically improved X Σ 1 /2 +2 , A Π 1 /2 2 , A Π 3 /2 2 , and B2Σ1/2 + potential-energy curves that are used to compute the A Π 3 /2 2 bound vibrational energies, the position of the D2 blue satellite peak, and the D1 and D2 pressure broadening and shifting coefficients, at the DZ, TZ, QZ, and CBS levels. Results are compared with previous calculations and experimental observation.

Diaqua-2κ2O-bis(μ-1-oxido-2-naphthoato-1:2κ3O1,O2:O2′;2:3κ3O2:O1,O2′-bis(1-oxido-2-naphthoato-1κ1O2,O2;3κ2O1,O2-hexapyridine-1κ2N,2κ2N,3κ2N-trimanganese(II/III pyridine disolvate dihydrate

Directory of Open Access Journals (Sweden)

Daqi Wang

2008-12-01

Full Text Available The title complex, [Mn3(C11H6O34(C5H5N6(H2O2]·2H2O·2C5H5N, is a trinuclear mixed oxidation state complex of overline1 symmetry. The three Mn atoms are six-coordinated in the shape of distorted octahedra, each coordinated with an O4N2 set of donor atoms, where the ligands exhibit mono- and bidentate modes. However, the coordination of the MnII ion located on the inversion centre involves water molecules at two coordination sites, whereas that of the two symmetry-related MnIII ions involves an O4N2 set of donor atoms orginating from the organic ligands. Intramolecular C—H...π interactions between neighbouring pyridine ligands stabilize this arrangement. A two-dimensional network parallel to (001 is formed by intermolecular O—H...O hydrogen bonds.

Crystal structures of (RS-N-[(1R,2S-2-benzyloxy-1-(2,6-dimethylphenylpropyl]-2-methylpropane-2-sulfinamide and (RS-N-[(1S,2R-2-benzyloxy-1-(2,4,6-trimethylphenylpropyl]-2-methylpropane-2-sulfinamide: two related protected 1,2-amino alcohols

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Matthew R. Carbone

2014-11-01

Full Text Available The title compounds, C22H31NO2S, (1, and C23H33NO2S, (2, are related protected 1,2-amino alcohols. They differ in the substituents on the benzene ring, viz. 2,6-dimethylphenyl in (1 and 2,4,6-trimethylphenyl in (2. The plane of the phenyl ring is inclined to that of the benzene ring by 28.52 (7° in (1 and by 44.65 (19° in (2. In the crystal of (1, N—H...O=S and C—H...O=S hydrogen bonds link molecules, forming chains along [100], while in (2, similar hydrogen bonds link molecules into chains along [010]. The absolute structures of both compounds were determined by resonance scattering.

Antimicrobial actions of the human epididymis 2 (HE2 protein isoforms, HE2alpha, HE2beta1 and HE2beta2

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French Frank S

2004-08-01

Full Text Available Abstract Background The HE2 gene encodes a group of isoforms with similarities to the antimicrobial beta-defensins. We demonstrated earlier that the antimicrobial activity of HE2 proteins and peptides is salt resistant and structure dependent and involves permeabilization of bacterial membranes. In this study, we further characterize the antimicrobial properties of HE2 peptides in terms of the structural changes induced in E. coli and the inhibition of macromolecular synthesis. Methods E. coli treated with 50 micro g/ml of HE2alpha, HE2beta1 or HE2beta2 peptides for 30 and 60 min were visualized using transmission and scanning electron microscopy to investigate the impact of these peptides on bacterial internal and external structure. The effects of HE2alpha, HE2beta1 and HE2beta2 on E. coli macromolecular synthesis was assayed by incubating the bacteria with 2, 10 and 25 micro g/ml of the individual peptides for 0–60 min and measuring the incorporation of the radioactive precursors [methyl-3H]thymidine, [5-3H]uridine and L-[4,5-3H(N]leucine into DNA, RNA and protein. Statistical analyses using Student's t-test were performed using Sigma Plot software. Values shown are Mean ± S.D. Results E. coli treated with HE2alpha, HE2beta1 and HE2beta2 peptides as visualized by transmission electron microscopy showed extensive damage characterized by membrane blebbing, thickening of the membrane, highly granulated cytoplasm and appearance of vacuoles in contrast to the smooth and continuous membrane structure of the untreated bacteria. Similarly, bacteria observed by scanning electron microscopy after treating with HE2alpha, HE2beta1 or HE2beta2 peptides exhibited membrane blebbing and wrinkling, leakage of cellular contents, especially at the dividing septa, and external accumulation of fibrous materials. In addition, HE2alpha, HE2beta1 and HE2beta2 peptides inhibited E. coli DNA, RNA and protein synthesis. Conclusions The morphological changes observed

Electronic and electrochemical properties of platinum(II) and platinum-mercury-carboxylato complexes containing 2-Me2NCH2C6H4, 2,6-(Me2NCH2)2C6H3- and 2-Me2NC6H4CH2 - ligands

NARCIS (Netherlands)

Koten, G. van; Ploeg, A.F.M.J. van der; Schmitz, J.E.J.; Linden, J.G.M. van der

1982-01-01

The organoplatinum(II) compounds [{2, 6-(Me{2}NCH{2}){2}C{6}H{3}}PtBr] and cis-[(C-N){2}Pt] (C-N = 2-Me{2}NCH{2}C{6}H{4}, 2-Me{2}NC{6}H{4}CH{2}) can be chemically irreversibly oxidized in the potential range 1.00 to 1.35 V vs. an Ag/AgCl electrode, whereas the organoplatinum@?mercury complexes

(Vapour + liquid) equilibria for (2,2-dimethoxypropane + methanol) and (2,2-dimethoxypropane + acetone)

International Nuclear Information System (INIS)

Jiang Hui; Li Haoran; Wang Congmin; Tan Taijun; Han Shijun

2003-01-01

The isothermal and isobaric (vapour + liquid) equilibria for (2,2-dimethoxypropane + methanol) and (2,2-dimethoxypropane + acetone) measured with an inclined ebulliometer are presented. The experimental results are analysed using the UNIQUAC equation with the temperature-dependent binary parameters with satisfactory results. Isobaric (vapour + liquid) equilibria data for these systems at p=99.99 kPa are compared with the literature data. Experimental vapour pressure of 2,2-dimethoxypropane are also included

Phase diagrams of systems of Sr2V2O7-M2V2O7 and of Ba2V2O7-M2V2O7 (M=Ca,Cd)

International Nuclear Information System (INIS)

Fotiev, A.A.; Zhuravlev, V.D.; Zhukov, V.P.

1982-01-01

Using the methods of X-ray phase and differential thermal anlyses phase equilibria in the systems Sr 2 V 2 O 7 -M 2 V 2 O 7 and Ba 2 V 2 O 7 -M 2 V 2 O 7 , where M--Ca, Cd, are studied, their phase diagrams being built. New double pyrovanadates Mosub(0.5)Srsub(1.5)Vsub(2)Osub(7) and MBaV 2 O 7 are found [ru

(3-Benzoyl-1,7,7-trimethylbicyclo[2.2.1]heptan-2-olato-κ2O,Obis[2-(2-pyridylphenyl-κ2C1,N]iridium(III

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Kaijun Luo

2011-11-01

Full Text Available The title compound, [Ir(C11H8N2(C17H19O2], has an octahedral coordination geometry around the IrIII atom, retaining the cis-C,C,trans–N,N chelate disposition of the two 2-phenylpyridine ligands. The chelate rings are nearly mutually perpendicular [the interplanar angles range from 85.48 (17 to 89.17 (19°]. The two 2-(2-pyridylphenyl ligands are approximately planar, with the plane of the phenyl ring being inclined to that of the pyridine ring by 2.3 (3 and 5.1 (3° in the two ligands. The interplanar angle between the phenyl ring in 3-benzoyl-camphor and the IrO2C3 chelate ring is 35.5 (2°.

4-Aza-1-azoniabicyclo?[2.2.2]octa?ne?2-amino?benzoate?2-amino?benzoic acid (1/1/1)

OpenAIRE

Arman, Hadi D.; Kaulgud, Trupta; Tiekink, Edward R. T.

2011-01-01

A 4-aza-1-azoniabicyclo[2.2.2]octane cation, a 2-aminobenzoate anion and a neutral 2-aminobenzoic acid molecule comprise the asymmetric unit of the title compound, C6H13N2+·C7H6NO2−·C7H7NO2. An intramolecular N—H...O hydrogen bond occurs in the anion and in the neutral 2-aminobenzoic acid molecule. The cation provides a charge-assisted N—H...O hydrogen bond to the anion, and the 2-aminobenzoic acid molecule forms an O—H...N hydrogen bo...

Investigation into the MgF2-NiF2, CaF2-NiF2, SrF2-NiF2 systems

International Nuclear Information System (INIS)

Ikrami, D.D.; Petrov, S.V.; Fedorov, P.P.; Ol'khovaya, L.A.; Luginina, A.A.; AN SSSR, Moscow. Inst. Fizicheskikh Problem; AN SSSR, Moscow. Inst. Kristallografii)

1984-01-01

Using the methods of differential thermal and X-ray phase analyses the systems MgF 2 -NiF 2 , CaF 2 -NiF 2 , SrF 2 -NiF 2 have been studied. In the system SrF 2 -NiF 2 the only orthorhombic compounds SrNiF 4 (a=14.43; b=3.93; c=5.66 (+-0.01 A)) is formed. SrNiF 4 density constitutes: dsub(X-ray)=4.60+-0.01 g/cm 3 , dsub(exp.)=4.60+-0.03 g/cm 3 . Refraction indices are as follows SrNiF 4 :Ng=1.500; Nsub(m)=1.497; Nsub(p)=1.479. SrNiF 4 magnetic ordering temperature Tsub(N) approximately 100 K

Na2MoO2As2O7

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Raja Jouini

2012-12-01

Full Text Available Disodium molybdenum dioxide diarsenate, Na2MoO2As2O7, has been synthesized by a solid-state reaction. The structure is built up from MoAs2O12 linear units sharing corners to form a three-dimensional framework containing tunnels running along the a-axis direction in which the Na+ cations are located. In this framework, the AsV atoms are tetrahedrally coordinated and form an As2O7 group. The MoVI atom is displaced from the center of an octahedron of O atoms. Two Na+ cations are disordered about inversion centres. Structural relationships between different compounds: A2MoO2As2O7 (A = K, Rb, AMOP2O7 (A = Na, K, Rb; M = Mo, Nb and MoP2O7 are discussed.

Physical properties and the Peierls instability of Li0.82[Pt(S2C2(CN)2)2] · 2H2O

DEFF Research Database (Denmark)

Ahmad, M. M.; Turner, D. J.; Underhill, A. E.

1984-01-01

The infrared reflectivity, the temperature-dependent conductivity, and thermopower of the one-dimensional conductor Li0.82[Pt(S2C2(CN)2)2] · 2H2O, LiPt(mnt), is presented. It undergoes a simple Peierls transition at Tc=215 K, which is not influenced by correlations or by cation ordering. The meta...

On the simultaneous Pell equations x 2 - (4m 2 - 1)y 2 = y 2 - pz 2 ...

African Journals Online (AJOL)

Let m be a positive integer, and let p be an odd prime. By using certain properties of Pell and quartic diophantine equations with some elementary number theory methods, we prove that the system of equations x2 - (4m2 - 1)y2 = 1 and y2 - pz2 = 1 has positive integer solutions (x, y, z) if and only if p ≡ 7(mod 8) and m = 1/4 ...

Photoluminescence properties of Eu2+-activated Ca2Y2Si2O9 phosphor

NARCIS (Netherlands)

Zhang, Zhijun; Delsing, A.C.A.; Notten, P.H.L.; Zhao, Jingtai; Hintzen, H.T.J.M.

2012-01-01

Eu2+-activated Ca2Y2Si2O9 phosphors with different Eu2+ concentrations have been prepared by a solid-state reaction method at high temperature and their photoluminescence (PL) properties were investigated. Photoluminescence results show that Eu2+-doped Ca2Y2Si2O9 can be efficiently excited by

161Dy Moessbauer spectroscopy of the intermetallic compounds DyNi2Si2, DyNi2Ge2 and DyAg2Si2

International Nuclear Information System (INIS)

Onodera, Hideya; Murata, Akifumi; Koizuka, Masaaki; Ohashi, Masayoshi; Yamaguchi, Yasuo

1994-01-01

161 Dy Moessbauer spectroscopic study has been performed on DyNi 2 Si 2 , DyNi 2 Ge 2 and DyAg 2 Si 2 in order to clarify microscopic properties of antiferromagnets with incommensurate and sinusoidally moment-modulated structure. The experiments were done using the standard 161 Tb Moessbauer sources prepared by neutron irradiation at the Japan Material Testing Reactor. The Moessbauer spectra of DyNi 2 Si 2 are analyzed satisfactorily by a single set of hyperfine parameters, and hence the sinusoidal moment-modulation is considered to be realized through a distribution of spin relaxation rate. The broadened spectra of DyNi 2 Ge 2 are fitted tentatively by three subspectra. It seems for DyNi 2 Ge 2 that the incommensurate arrangement of Dy moments differed in magnitude as well as the distribution of spin relaxation rate originates the moment modulation. The fact that the spectrum of DyAg 2 Si 2 at 3 K consists of two distinct subspectra ensures the complicated antiferromagnetic structure where two kinds of Dy moments differed in magnitude are arranged noncollinearly. (author)

2-Methylpropan-2-aminium 2-(methoxycarbonylbenzoate

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Jian Li

2011-10-01

Full Text Available In the title compound, C4H12N+·C9H7O4−, two C atoms and the N atom of the cation lie on a mirror plane, while all the atoms of the anion are disordered about a mirror plane. In the crystal, N—H...O hydrogen bonds link the components into chains along [010]. In the anion, the mean planes of the methoxycarbonyl and carboxylate groups form dihedral angles of 83.0 (2 and 83.2 (2°, respectively, with the aromatic ring.

Theoretical study on the photolysis mechanism of 2,3-diazabicyclo[2.2.2]oct-2-ene.

Science.gov (United States)

Chen, Hui; Li, Shuhua

2005-09-28

A CASPT2/CASSCF study has been carried out to investigate the mechanism of the photolysis of 2,3-diazabicyclo[2.2.2]oct-2-ene (DBO) under direct and triplet-sensitized irradiation. By exploring the detailed potential energy surfaces including intermediates, transition states, conical intersections, and singlet/triplet crossing points, for the first excited singlet (S(1)) and the low-lying triplet states (T(1), T(2), and T(3)), we provide satisfactory explanations of many experimental findings associated with the photophysical and photochemical processes of DBO. A key finding of this work is the existence of a significantly twisted S(1) minimum, which can satisfactorily explain the envelope of the broad emission band of DBO. It is demonstrated that the S(1) (n-pi*) intermediate can decay to the T(1) (n-pi*) state by undergoing intersystem crossing (rather inefficient) to the T(2) (pi-pi*) state followed by internal conversion to the T(1) state. The high fluorescence yield and the extraordinarily long lifetime of the singlet excited DBO are due to the presence of relatively high barriers, both for intersystem crossing and for C-N cleavage. The short lifetime of the triplet DBO is caused by fast radiationless decay to the ground state.

Stabilization and reactivity of a terminal phosphidounit on Pt(II). Synthesis and X-ray structure of cationic diphelylphosphine [Pt{C6H3(CH2NMe2)2-2,6}(PHPh2)][CF3SO3] and Diphenyl-phosphido Bridged Pt(II)-Pd(II) Complex [Pt{C6H3(CH2NMe2)2-2,6} (µ-PPh2) Pd(C6H4CH2NMe2-2)(H2O)][BF4] CH2Cl2

NARCIS (Netherlands)

Koten, G. van; Maassarani, F.; Davidson, M.F.; Wehman-Ooyevaar, ICM; Grove, D.M.; Koten, M.A. van; Smeets, W.J.J.; Spek, A.L.

1995-01-01

Reaction of diphenylphosphine with the complexes [Pt(NCN)(H{2}O)]X (NCN = C{6}H{3}(CH{2}NMe{2}){2}-2, 6; X = BF{4} (1a), OSO{2}CF{3} (1b)) leads to substitution of the H{2}O ligand to afford the ionic Pt(II) complexes [Pt(NCN)(PHPh{2})]X (X = BF{4} (2a), OSO{2}CF{3} (2b)). The X-ray structure of the

The synthesis of [2-3H2] taurine and [2-3H2] hypotaurine

International Nuclear Information System (INIS)

Fellman, J.H.

1981-01-01

The synthesis of [2- 3 H 2 ]-2-aminoethanesulfonate [2- 3 H]-taurine by the reduction of cyanomethanesulfonic acid with tritium gas is described. The conversion of [2- 3 H]-taurine and its 14 C and 35 S isotopic forms to 2-aminoethanesulfinate (hypotaurine) was accomplished by converting taurine to its corresponding sulfonyl chloride and reducing the latter with metallic zinc. (author)

Crystal and molecular structure of 2,2’-(quinoxaline-2,3-diyl)dipyridinium dinitrate (H_2L)(NO_3)_2

International Nuclear Information System (INIS)

Egorova, O. A.; Polyakova, I. N.; Sergienko, V. S.; Davydov, V. V.

2016-01-01

The crystal structure of 2,2’-(quinoxaline-2,3-diyl)dipyridinium dinitrate (H_2L)(NO_3)_2 is studied by X-ray diffraction (T = 150 K, R1 = 0.0467). The H_2L"2"+ cation is located on the twofold rotation axis and connected with two NO_3"− anions by strong N–H···O hydrogen bonds. Planar quinoxaline fragments of cations form stacks with the interplanar spacing of 3.308 Å. The structure of the diprotonated H_2L"2"+ cation is compared with those of the monoprotonated H_2L"2"+ cation and neutral L molecule.

Magnetism of CuCl{sub 2}·2D{sub 2}O and CuCl{sub 2}·2H{sub 2}O, and of CuBr{sub 2}·6H{sub 2}O

Energy Technology Data Exchange (ETDEWEB)

DeFotis, G.C., E-mail: gxdefo@wm.edu [Department of Chemistry, College of William and Mary, Williamsburg, VA 23187 (United States); Hampton, A.S.; Van Dongen, M.J.; Komatsu, C.H.; Benday, N.S.; Davis, C.M. [Department of Chemistry, College of William and Mary, Williamsburg, VA 23187 (United States); Hays, K.; Wagner, M.J. [Department of Chemistry, George Washington University, Washington, D.C. 20052 (United States)

2017-07-15

Highlights: • CuCl{sub 2}·2D{sub 2}O is examined magnetically and compared with CuCl{sub 2}·2H{sub 2}O. • Slightly lower magnetic characteristic temperatures occur for deuterated dihydrate. • The new compound CuBr{sub 2}·6H{sub 2}O is examined magnetically. • Unexpected relationships appears between magnetic behaviors of CuBr{sub 2}·6H{sub 2}O and CuBr{sub 2}. • Two alternative monoclinic unit cells can account for diffraction data on CuBr{sub 2}·6H{sub 2}O. - Abstract: The magnetic properties of little examined CuCl{sub 2}·2D{sub 2}O are studied and compared with those of CuCl{sub 2}·2H{sub 2}O. New CuBr{sub 2}·6H{sub 2}O is also examined. Susceptibility maxima appear for chlorides at 5.35 and 5.50 K, in the above order, with estimated antiferromagnetic ordering at 4.15 and 4.25 K. Curie-Weiss fits yield g of 2.210 and 2.205, and Weiss θ of −6.0 and −4.7 K, respectively, in χ{sub M} = C/(T − θ). One-dimensional Heisenberg model fits to susceptibilities, including interchain exchange in a mean-field approximation, are performed. Interchain exchange is significant but much weaker than intrachain. The bromide hexahydrate strongly differs magnetically from any chloride hydrate, but exhibits notable similarities and differences compared to previously studied CuBr{sub 2}. A broad susceptibility maximum occurs near 218 K, only 4% lower than for CuBr{sub 2}, but with almost twice the magnitude. Powder X-ray diffraction data for CuBr{sub 2}·6H{sub 2}O may be best accounted for by a monoclinic unit cell that is metrically orthorhombic. The volume per formula unit is consistent with trends in metal ionic radii. However, an alternative monoclinic cell with 5% smaller volume more readily rationalizes the magnetism.

Determination and modeling for the solubility of Na_2WO_4·2H_2O and Na_2MoO_4·2H_2O in the (Na"+ + MoO_4"2"− + WO_4"2"− + SO_4"2"− + H_2O) system

International Nuclear Information System (INIS)

Ning, Pengge; Xu, Weifeng; Cao, Hongbin; Xu, Hongbin

2016-01-01

Highlights: • The solubility of Na_2MoO_4·2H_2O and Na_2WO_4·2H_2O in Na_2MoO_4–Na_2WO_4–Na_2SO_4–H_2O were performed. • The solubility of sodium tungstate dihydrate in Na_2WO_4–Na_2SO_4–H_2O was determined. • The new model was established via regressing the published and the determined data. • The Pitzer parameter and the solubility product constant of the salt in solution were calculated. • The model was used to estimate the solubility of the sodium molybdate and sodium tungstate. - Abstract: The solubility of sodium tungstate dihydrate and sodium molybdate dihydrate in the (Na_2MoO_4 + Na_2WO_4 + Na_2SO_4 + H_2O) system was studied using experimental and calculated methods. The osmotic coefficient of sodium tungstate was fitted to calculate the thermodynamics parameters of (Na_2WO_4 + H_2O) system. The solubility of sodium tungstate dihydrate was determined using the dynamic method in Na_2WO_4–Na_2SO_4–H_2O to establish the new model which can provide an estimate the solubility of sodium tungstate dihydrate in various conditions, combined with the data published, the solubility of sodium tungstate dihydrate and the sodium molybdate dihydrate in quaternary system of (Na_2MoO_4 + Na_2WO_4 + Na_2SO_4 + H_2O) was estimated using the parameters of the two ternary systems of (Na_2WO_4 + Na_2SO_4 + H_2O) and (Na_2MoO_4 + Na_2SO_4 + H_2O). The results show that the AARD is always small and the calculated value is basically consistent with the experimental values for the system studied.

Measurement of the hyperfine structure of the 4d2D3/2,5/2 levels and isotope shifts of the 4p2P3/2->4d2D3/2 and 4p2P3/2->4d2D5/2 transitions in gallium 69 and 71

International Nuclear Information System (INIS)

Rehse, Steven J.; Fairbank, William M.; Lee, Siu Au

2001-01-01

The hyperfine structure of the 4d 2 D 3/2,5/2 levels of 69,71 Ga is determined. The 4p 2 P 3/2 ->4d 2 D 3/2 (294.50-nm) and 4p 2 P 3/2 ->4d 2 D 5/2 (294.45-nm) transitions are studied by laser-induced fluorescence in an atomic Ga beam. The hyperfine A constant measured for the 4d 2 D 5/2 level is 77.3±0.9 MHz for 69 Ga and 97.9± 0.7 MHz for 71 Ga (3σ errors). The A constant measured for the 4d 2 D 3/2 level is -36.3±2.2 MHz for 69 Ga and -46.2±3.8 MHz for 71 Ga. These measurements correct sign errors in the previous determination of these constants. For 69 Ga the hyperfine B constants measured for the 4d 2 D 5/2 and the 4d 2 D 3/2 levels are 5.3±4.1 MHz and 4.6±4.2 MHz, respectively. The isotope shift is determined to be 114±8 MHz for the 4p 2 P 3/2 ->4d 2 D 3/2 transition and 115±7 MHz for the 4p 2 P 3/2 ->4d 2 D 5/2 transition. The lines of 71 Ga are shifted to the blue. This is in agreement with previous measurement. [copyright] 2001 Optical Society of America

2-[(1-Benzamido-2-methoxy-2-oxoethylamino]benzoic Acid

Directory of Open Access Journals (Sweden)

Alami Anouar

2013-01-01

Full Text Available The carboxylic α,α-diaminoester 2-[(1-benzamido-2-methoxy-2-oxoethyl amino]benzoic acid is obtained by N-alkylation of methyl α-azido glycinate N-benzoylated with 2-aminobenzoic acid.

Nitrogen heteroaromatic cations by [2+2+2] cycloaddition

Czech Academy of Sciences Publication Activity Database

Čížková, Martina; Kolivoška, Viliam; Císařová, I.; Šaman, David; Pospíšil, Lubomír; Teplý, Filip

2011-01-01

Roč. 9, č. 2 (2011), s. 450-462 ISSN 1477-0520 R&D Projects: GA ČR GA203/09/1614; GA ČR GA203/09/0705; GA MŠk OC 140 Institutional research plan: CEZ:AV0Z40550506; CEZ:AV0Z40400503 Keywords : modular synthesis * N-heteroaromatic cation * [2+2+2] cycloaddition Subject RIV: CC - Organic Chemistry Impact factor: 3.696, year: 2011

Construction of Δm2--sin2 2θ plots

International Nuclear Information System (INIS)

Snyder, R.

1991-01-01

In the two-flavor approximation, the probability for a neutrino to oscillate from one flavor to the other is given by Ρ νa → νb = sin 2 2θ sin 2 (1.27 Δm 2 L/E ν ) where θ is the mixing angle, Δm 2 = |m νa 2 - m νb 2 | is measured in (eV/c 2 ) 2 , L, the distance from the source, is measured in km, and E, the beam energy, is measured in GeV. If either Δm 2 or sin 2 2Θ is zero, there is no oscillation. They might also have small, non-zero values, causing the oscillations to be so small as to be unobservable in a particular experiment. They may also have values which allow us to determine the probability of oscillation, but so far no compelling evidence for oscillation exists. The universal method of portraying what region of parameter space is explored by a neutrino oscillation experiment is to mark off an area on a Δm 2 vs. sin 2 2θ plot. Typically, a line is graphed, with the claim that if the experiment finds not evidence of oscillation, one can, for example, be 90% certain that Δm 2 and sin 2 2θ lie within the region below and to the left of the line. Since these plots are so widely used, it is useful to understand the process by which they are created

trans-(2-Benzoylpyridine-κ2N,Odichlorido[2-(2-pyridylcarbonylphenyl-κ2C1,N]iridium(III dichloromethane solvate

Directory of Open Access Journals (Sweden)

2009-03-01

Full Text Available The title compound, [Ir(C12H8NOCl2(C12H9NO]·CH2Cl2, which was obtained from the reaction of iridium(III chloride trihydrate and 2-benzoylpyridine, contains an IrIII atom coordinated by two N, one O, one C and two Cl atoms in trans positions, forming a distorted octahedral environment. The solvent molecule CH2Cl2 is disordered over two positions with an occupancy of 0.8:0.2.

Thermal decomposition of (UO{sub 2})O{sub 2}(H{sub 2}O){sub 2}·2H{sub 2}O: Influence on structure, microstructure and hydrofluorination

Energy Technology Data Exchange (ETDEWEB)

Thomas, R. [Univ. Lille, CNRS, Centrale Lille, ENSCL, Univ. Artois, UMR 8181 - UCCS - Unité de Catalyse et Chimie du Solide, F-59000 Lille (France); Hall de Recherche de Pierrelatte, AREVA NC, BP 16, 26701 Pierrelatte (France); Rivenet, M., E-mail: murielle.rivenet@ensc-lille.fr [Univ. Lille, CNRS, Centrale Lille, ENSCL, Univ. Artois, UMR 8181 - UCCS - Unité de Catalyse et Chimie du Solide, F-59000 Lille (France); Berrier, E. [Univ. Lille, CNRS, Centrale Lille, ENSCL, Univ. Artois, UMR 8181 - UCCS - Unité de Catalyse et Chimie du Solide, F-59000 Lille (France); Waele, I. de [Université de Lille, CNRS, UMR 8516 – LASIR - Laboratoire de Spectrochimie Infrarouge et Raman, F-59000 Lille (France); Arab, M.; Amaraggi, D.; Morel, B. [Hall de Recherche de Pierrelatte, AREVA NC, BP 16, 26701 Pierrelatte (France); Abraham, F. [Univ. Lille, CNRS, Centrale Lille, ENSCL, Univ. Artois, UMR 8181 - UCCS - Unité de Catalyse et Chimie du Solide, F-59000 Lille (France)

2017-01-15

The thermal decomposition of uranyl peroxide tetrahydrate, (UO{sub 2})O{sub 2}(H{sub 2}O){sub 2}.2H{sub 2}O, was studied by combining high temperature powder X-ray diffraction, scanning electron microscopy, thermal analyses and spectroscopic techniques (Raman, IR and {sup 1}H NMR). In situ analyses reveal that intermediates and final uranium oxides obtained upon heating are different from that obtained after cooling at room temperature and that the uranyl precursor used to synthesize (UO{sub 2})O{sub 2}(H{sub 2}O){sub 2}·2H{sub 2}O, sulfate or nitrate, has a strong influence on the peroxide thermal behavior and morphology. The decomposition of (UO{sub 2})O{sub 2}(H{sub 2}O){sub 2}·2H{sub 2}O ex sulfate is pseudomorphic and leads to needle-like shaped particles of metastudtite, (UO{sub 2})O{sub 2}(H{sub 2}O){sub 2}, and UO{sub 3-x}(OH){sub 2x}·zH{sub 2}O, an amorphous phase found in air in the following of (UO{sub 2})O{sub 2}(H{sub 2}O){sub 2} dehydration. (UO{sub 2})O{sub 2}(H{sub 2}O){sub 2}·2H{sub 2}O and the compounds resulting from its thermal decomposition are very reactive towards hydrofluorination as long as their needle-like morphology is kept.

ZrCu2P2 and HfCu2P2 phosphides and their crystal structure

International Nuclear Information System (INIS)

Lomnitskaya, Ya.F.

1986-01-01

Isostructural ZrCu 2 P 2 and HfCu 2 P 2 compounds are prepared for the first time. X-ray diffraction analysis (of powder, DRON-2.0 diffractometer, FeKsub(α) radiation) was used to study crystal structure of HfCu 2 P 2 phosphide belonging to the CaAl 2 Si 2 structural type (sp. group P anti 3 m 1, R=0.095). Lattice parameters the compounds are as follows: for ZrCu 2 P 2 a=0.3810(1), c=0.6184(5); for HfCu 2 P 2 a=0.3799(1), c=0.6160(2) (nm). Atomic parameters in the HfCu 2 P 2 structure and interatomic distances are determined

First identification and thermodynamic characterization of the ternary U(VI) species, UO2(O2)(CO3)2(4-), in UO2-H2O2-K2CO3 solutions.

Science.gov (United States)

Goff, George S; Brodnax, Lia F; Cisneros, Michael R; Peper, Shane M; Field, Stephanie E; Scott, Brian L; Runde, Wolfgang H

2008-03-17

In alkaline carbonate solutions, hydrogen peroxide can selectively replace one of the carbonate ligands in UO2(CO3)3(4-) to form the ternary mixed U(VI) peroxo-carbonato species UO2(O2)(CO3)2(4-). Orange rectangular plates of K4[UO2(CO3)2(O2)].H2O were isolated and characterized by single crystal X-ray diffraction studies. Crystallographic data: monoclinic, space group P2(1)/ n, a = 6.9670(14) A, b = 9.2158(10) A, c = 18.052(4) A, Z = 4. Spectrophotometric titrations with H 2O 2 were performed in 0.5 M K 2CO 3, with UO2(O2)(CO3)2(4-) concentrations ranging from 0.1 to 0.55 mM. The molar absorptivities (M(-1) cm(-1)) for UO2(CO3)3(4-) and UO2(O2)(CO3)2(4-) were determined to be 23.3 +/- 0.3 at 448.5 nm and 1022.7 +/- 19.0 at 347.5 nm, respectively. Stoichiometric analyses coupled with spectroscopic comparisons between solution and solid state indicate that the stable solution species is UO2(O2)(CO3)2(4-), which has an apparent formation constant of log K' = 4.70 +/- 0.02 relative to the tris-carbonato complex.

VUV photoionization cross sections of HO2, H2O2, and H2CO.

Science.gov (United States)

Dodson, Leah G; Shen, Linhan; Savee, John D; Eddingsaas, Nathan C; Welz, Oliver; Taatjes, Craig A; Osborn, David L; Sander, Stanley P; Okumura, Mitchio

2015-02-26

The absolute vacuum ultraviolet (VUV) photoionization spectra of the hydroperoxyl radical (HO2), hydrogen peroxide (H2O2), and formaldehyde (H2CO) have been measured from their first ionization thresholds to 12.008 eV. HO2, H2O2, and H2CO were generated from the oxidation of methanol initiated by pulsed-laser-photolysis of Cl2 in a low-pressure slow flow reactor. Reactants, intermediates, and products were detected by time-resolved multiplexed synchrotron photoionization mass spectrometry. Absolute concentrations were obtained from the time-dependent photoion signals by modeling the kinetics of the methanol oxidation chemistry. Photoionization cross sections were determined at several photon energies relative to the cross section of methanol, which was in turn determined relative to that of propene. These measurements were used to place relative photoionization spectra of HO2, H2O2, and H2CO on an absolute scale, resulting in absolute photoionization spectra.

Flow microreactor synthesis of 2,2-disubstituted oxetanes via 2-phenyloxetan-2-yl lithium

Directory of Open Access Journals (Sweden)

Degennaro Leonardo

2016-01-01

Full Text Available A mild and sustainable synthesis of 2,2-disubstituted oxetanes has been achieved through the use of a flow microreactor system. By controlling the residence time a highly unstable intermediate such as 2-phenyloxetan-2-yl lithium can be generated and trapped with various electrophiles affording in moderate to good yields 2-substituted-2-phenyloxetanes at higher temperatures with respect to macrobatch-mode where –78 °C is required.

Insertion Chemistry of Cp*2Y(2-pyridyl) and Molecular Structure of the Unexpected CO Insertion Product (Cp*2Y)2(μ-η2 : η2-OC(NC5H4)2)

NARCIS (Netherlands)

Deelman, Berth-Jan; Stevels, Willem M.; Teuben, Jan H.; Lakin, Miles T.; Spek, Anthony L.

1994-01-01

Pyridine is metalated selectively at the 2-position by (Cp*2YH)2 to yield Cp*2Y(2-pyridyl) (1). Compound 1 reacts with H2 to give the hydride addition product Cp*2Y(NC5H6) (2). With THF and pyridine the adducts Cp*2Y(η2-2-pyridyl)(THF) (3) and Cp*2Y(η1-2-pyridyl)(py) (4) are formed. The pyridine

Magnetic properties of the UMn2-UFe2 and UMn2-UCO2 system alloys

International Nuclear Information System (INIS)

Meskhishvili, A.I.; Pletyushkin, V.A.; Slovyanskikh, V.K.; Chechernikov, V.I.; Shavishvili, T.M.

1978-01-01

The magnetic properties of compounds UMn 2 and UCo 2 , and solid solutions UMn 2 -UFe 2 and UMn 2 -UCo 2 have been examined. It has been established, that in substituting iron ions with manganese ions, the temperature of the ferromagnetic transformation of UFe 2 decreases, and within the region of 50 at.% UFe 2 the ferromagnetic ordering disappears. The Curie-Weiss law holds within a limited temperature range. In the solid solutions of two paramagnets UMn 2 and UCo 2 , which are independent of temperature, at a concentration of 45 to 50 at.% UCo 2 , the magnetic susceptibility and its dependence on temperature attain their maximum values. The results obtained are connected with the collectivization of d-, f-, and s-electrons of an alloy

2-minute Gridded Global Relief Data (ETOPO2) v2

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Two-minute gridded global relief for both ocean and land areas are available in the ETOPO2v2 (2006) database. ETOPO2v2 replaced ETOPO2 (2001). The historic 2-minute...

Convenient synthesis of 2,2-Dimethyl-3,4-dihydro-2 H-pyrano[2,3- b]quinolines

Digital Repository Service at National Institute of Oceanography (India)

Parsekar, S.B.; Amonkar, C.P.; Parameswaran, P.S.; Tilve, S.G.

A convenient general synthesis of 2,2-dimethyl-3,4-dihydro-2H-pyrano[2,3-b]quinolines using the Wittig reaction is described. The o-nitrobenzaldehydes (1a-d) on reaction with phosphorane 2 provided (E)-ethyl-a-(2,2-dimethylprop-2-ene)-2...

Cationic polyhydrido cluster complexes. Crystal and molecular structures of (Ir3(Ph2P(CH2)3PPh2)3(H)7(CO))2+ and (Ir3(Ph2P(CH2)2(2-py))3(H)7)2+

International Nuclear Information System (INIS)

Hsienhau Wang; Casalnuovo, A.L.; Johnson, B.J.; Mueting, A.M.; Pignolet, L.H.

1988-01-01

Two new cationic polyhydrido cluster complexes of iridium have been synthesized and characterized by single-crystal x-ray diffraction and by ir and 1 H and 31 P NMR spectroscopy (Ir 3 (dppp) 3 (H) 7 (CO)) 2+ (2) and (Ir3 (PN) 3 (H) 7)2+ (5), where dppp = 1,3-bis(diphenylphosphino)propane and PN = 1-(2-pyridyl)-2-(diphenylphosphino)ethane, were synthesized by the reaction of CO with (Ir 3 (dppp) 3 (H) 7 ) 2+ (1) in CH 2 Cl 2 solution and H 2 with (Ir(PN)(COD)) + (4) in CH 3 OH solution, respectively. Crystal structures for both compounds is reported. The hydride positions were not located in the crystal structure analyses but were deduced from structural and 1 H NMR data. The molecular structure of 2 consists of a bilateral triangle of three iridium atoms with a carbonyl at the vertex and a chelating dppp ligand on each iridium atom. 1 H NMR data with use of acetone-d 6 as solvent showed that 2 possesses four doubly bridging hydrides and three terminal hydrides, yielding C 1 symmetry. The molecular structure of 5 consists of an approximately equilateral triangle of three iridium atoms (average Ir-Ir distance 2.746 (1) angstrom) with one PN ligand chelated to each iridium atom. 1 H NMR analysis, with use of CD 2 Cl 2 as solvent, showed that 5 has one triply bridging hydride and six terminal hydrides, giving C 3 symmetry. (Ir 3 (dppp) 3 (H) 7 (CH 3 C 6 H 4 NC)) 2+ (3) a complex structurally analogous to 2, was synthesized from 1 and p-tolyl isocyanide in CH 2 Cl 2 solution and characterized by ir and 1 H and 31 P NMR spectroscopy. 44 refs., 3 figs., 3 tabs

Comparative toxicity of VO3-, CrO42-, Mn2+, Co2+, Ni2+, Cu2+, Zn2+, and Cd2+ to lettuce seedlings

International Nuclear Information System (INIS)

Berry, W.L.

1978-01-01

Lettuce seeds imbibed, germinated, and grown in a 0.1-strength modified Hoagland culture solution were subjected to a series of increasing concentrations of individual heavy metals up to and exceeding lethal levels. After an exposure of 5 days, seedlings were harvested, examined, and measured to determine toxic effects. A log--log plot of root length (yield) vs. heavy metal concentration was made for each metal to produce a dose response curve. The curves showed a growth plateau at low concentrations of the respective metals which was equivalent to the growth of the control. All metals inhibited root growth and caused lethal toxicity in the sub- and low-milliequivalent range. When concentrations of the tested metals exceeded their thresholds of acute toxicity, root growth was inhibited. In the zone of inhibition, between the acute toxic threshold and complete inhibition, the log--log dose response curves were approximately linear or were a series of linear steps. The threshold toxicity and the response slope were characteristic for each metal. Seedling lettuce showed a monophasic response to VO 3 - , Cu 2+ , and Zn 2+ ; a biphasic response to CrO 4 2 -, Mn 2+ , Ni 2+ , and Cd 2+ ; and a quadraphasic response to Co 2+ . The acute toxicity threshold on an equivalent basis increased according to the following sequence: Cd 2+ much less than VO 3 - 2+ 2+ 2+ 4 2- 2+ much less than Mn 2+ . On this basis, Cd 2+ is the most toxic of the trace elements tested

Structure of human ubiquitin-conjugating enzyme E2 G2 (UBE2G2/UBC7)

International Nuclear Information System (INIS)

Arai, Ryoichi; Yoshikawa, Seiko; Murayama, Kazutaka; Imai, Yuzuru; Takahashi, Ryosuke; Shirouzu, Mikako; Yokoyama, Shigeyuki

2006-01-01

The crystal structure of human UBE2G2/UBC7 was solved at 2.56 Å resolution. The superimposition of UBE2G2 on UbcH7 in a c-Cbl–UbcH7–ZAP70 ternary complex suggested that the two loop regions of UBE2G2 interact with the RING domain in a similar way as UbcH7. The human ubiquitin-conjugating enzyme E2 G2 (UBE2G2/UBC7) is involved in protein degradation, including a process known as endoplasmic reticulum-associated degradation (ERAD). The crystal structure of human UBE2G2/UBC7 was solved at 2.56 Å resolution. The UBE2G2 structure comprises a single domain consisting of an antiparallel β-sheet with four strands, five α-helices and two 3 10 -helices. Structural comparison of human UBE2G2 with yeast Ubc7 indicated that the overall structures are similar except for the long loop region and the C-terminal helix. Superimposition of UBE2G2 on UbcH7 in a c-Cbl–UbcH7–ZAP70 ternary complex suggested that the two loop regions of UBE2G2 interact with the RING domain in a similar way to UbcH7. In addition, the extra loop region of UBE2G2 may interact with the RING domain or its neighbouring region and may be involved in the binding specificity and stability

K2V2O2(AsO42

Directory of Open Access Journals (Sweden)

Thierry Roisnel

2012-07-01

Full Text Available The vanadium oxide arsenate with formula K2V2O2(AsO42, dipotassium divanadium(IV dioxide diarsenate, has been synthesized by solid-state reaction in an evacuated silica ampoule. Its structure is isotypic with K2V2O2(PO42. The framework is built up from corner-sharing VO6 octahedra and AsO4 tetrahedra, creating an infinite [VAsO8]∞ chain running along the a- and c-axis directions. The K+ cations are located in hexagonal tunnels, which are delimited by the connection of the [VAsO8]∞ chains.

Syntheses, and crystal and electronic structures of the new Zintl phases Na2ACdSb2 and K2ACdSb2 (A=Ca, Sr, Ba, Eu, Yb): Structural relationship with Yb2CdSb2 and the solid solutions Sr2-xAxCdSb2, Ba2-xAxCdSb2 and Eu2-xYbxCdSb2

International Nuclear Information System (INIS)

Saparov, Bayrammurad; Saito, Maia; Bobev, Svilen

2011-01-01

Presented are the details of the syntheses, crystal and electronic structures of a new family of Zintl phases Na 2 ACdSb 2 and K 2 ACdSb 2 (A=Ca, Sr, Ba, Eu, Yb), as well as the solid solutions Sr 2-x A x CdSb 2 , Ba 2-x A x CdSb 2 and Eu 2-x Yb x CdSb 2 . The structures of Na 2 ACdSb 2 and K 2 ACdSb 2 (A=Ca, Sr, Ba, Eu, Yb) were determined to be of a new type with the non-centrosymmetric space group Pmc2 1 (no. 26), Pearson symbol oP12, with lattice parameters a=4.684(1)-4.788(1) A; b=9.099(3)-9.117(2) A; c=7.837(1)-8.057(2) A for the Na 2 ACdSb 2 series, and a=4.6637(9)-5.0368(8) A; b=9.100(2)-9.8183(15) A; and c=7.7954(15)-8.4924(13) A for K 2 ACdSb 2 , respectively. The solid solutions Sr 2-x A x CdSb 2 , Ba 2-x A x CdSb 2 and Eu 2-x Yb x CdSb 2 (x∼1) are isostructural and isoelectronic to the recently reported Yb 2 CdSb 2 (space group Cmc2 1 (no. 36), Pearson symbol cP20). All discussed structures are based upon CdSb 2 4- polyanionic layers, similar to the ones observed in Yb 2 CdSb 2 , with various alkali- and/or alkaline-earth cations coordinated to them. Magnetic susceptibility and Seebeck coefficient measurements on selected Eu 2-x Yb x CdSb 2 samples, taken at low temperatures up to 300 K, are also reported. -- Graphical abstract: The quaternary Zintl phases Na 2 ACdSb 2 and K 2 ACdSb 2 (A=Ca, Sr, Ba, Eu, Yb) with novel layered structures have been synthesized for the first time and structurally characterized by single-crystal X-ray diffraction. Reported as well are the results from crystallographic and property studies of the closely related solid solutions Sr 2-x A x CdSb 2 , Ba 2-x A x CdSb 2 (x∼1), and Eu 2-x Yb x CdSb 2 (1 2 ACdSb 2 and K 2 ACdSb 2 (A=Ca, Sr, Ba, Eu, Yb) are new quaternary Zintl phases. → Sr 2-x A x CdSb 2 , Ba 2-x A x CdSb 2 (x∼1), and Eu 2-x Yb x CdSb 2 (1 4 tetrahedra. → Eu 2-x Yb x CdSb 2 (1< x<2) exhibit high Seebeck coefficient (217 μV/K at RT).

Comparative study of pinning and creep in Tl2Ba2CaCu2O8 and Bi2Sr2CaCu2O8 single crystals

International Nuclear Information System (INIS)

Oussena, M.; Porter, S.; Volkozub, A.V.; de Groot, P.A.J.; Lanchester, P.C.; Ogborne, D.; Weller, M.T.; Balakrishnan, G.; Paul, D.M.

1993-01-01

We have compared the pinning and creep in two identically shaped single crystals, Tl 2 Ba 2 CaCu 2 O 8 (Tl 2:2:1:2) and Bi 2 Sr 2 CaCu 2 O 8 (Bi 2:2:1:2) using magnetometry. The critical current density, J c , deduced from the M-H hysteresis loops is found to be the highest in Bi 2:2:1:2 at low temperatures (T c , in this temperature range, is similar for both crystals. At higher temperatures, J c is found to decrease more rapidly with magnetic field in Bi 2:2:1:2 than in Tl 2:2:1:2. The critical current also decreases more quickly with temperature in Bi 2:2:1:2 leading to a vanishing J c at temperatures lower than in the case of Tl 2:2:1:2. I-V characteristic curves have been obtained from measurements of magnetic-sweep-rate dependencies of the hysteresis loops. We have found that the characteristic temperature at which flux motion becomes important is significantly higher in Tl 2:2:1:2 than in Bi 2:2:1:2

Lanthanide complexes of 2-aminoacetophenone and 2-acetylaminoacetophenone 2-thenoylhydrazone

International Nuclear Information System (INIS)

Singh, Praveen K.; Singh, B.

1998-01-01

The reaction of lanthanide chlorides with 2-aminoacetophenone-2-thenoyl- hydrazone and 2-acetylaminoacetophenone-2-thenoylhydrazone yield complexes of the type [Ln(aath) 2 Cl 2 (H 2 )O]Cl and [Ln(acaath) 2 Cl 2 ]Cl. These complexes have been characterized by molar conductance, magnetic susceptibility, TGA, DTA and various spectroscopic techniques such as mass, IR, NMR, UV - visible and emission spectra. Mass spectral data indicate the aath complexes to be monomeric. Thermal stability of the complexes and presence of one water molecule in aath complex is indicated by TGA and DTA studies. Electronic spectra of Pr(III) and Nd(III) complexes show the coordination number to be nine and eight around the metal ions in the aath and acaath complexes, respectively. This has also been inferred from the spectral features of the hypersensitive transition in the Nd(III) complexes. The lowering in coordination number from aath to acaath complexes may be attributed to increase in chelate ring size and/or steric/inductive effect of methyl group. Emission spectral studies of the [Eu(aath) 2 Cl 2 (H 2 O)]Cl and [Eu(acaath) 2 Cl 2 ]Cl suggest tricapped trigonal prismatic (D 3h ) and square antiprismatic (D 4d ) geometry, respectively. (author)

Zn2+, Cd2+, Hg2+ thiolates - derivatives of 2, 3, 5-trifluoro-4,6-bis(trifluoromethyl)thiophenol and heptafluoro-2-thionaphthol

International Nuclear Information System (INIS)

Larionov, S.V.; Kirichenko, V.N.; Platonov, V.E.; Maksimov, A.M.; Rodionov, P.P.; Fadeeva, V.P.; Oglezneva, I.M.; Lisojvan, V.I.; AN SSSR, Novosibirsk

1992-01-01

Zn 2+ , Cd 2+ , Hg 2+ coordination compounds with 2, 3, 5 -trifluoro- 4,6 bis(trifluoromethyl)trhiophenol (MHal) and heptafluoro-2-thionophthal (HT) of ZnHal 2 (CH 3 OH), CdHal 2 , HgHal 2 and MT 2 (M=Zn, Cd, Hg) composition, are obtained. Complexes are studied using thermal and X-ray phase analysis, vapour phase osmometry and IR spectroscopy, ZnHal 2 (CH 3 OH), CdHal 2 , ZnT 2 , HgHfl 2 , HgT 2 compounds in acetone solutions are in monomeric state, while in CdT 2 commeric particles. Frequencies of mostly valent vibrations of Cd-S bond are observed at 241 (CdHal 2 ), 225 (CdT 2 )

Intramolecular ketenimine-ketenimine [2 + 2] and [4 + 2] cycloadditions.

Science.gov (United States)

Alajarín, Mateo; Bonillo, Baltasar; Sanchez-Andrada, Pilar; Vidal, Angel; Bautista, Delia

2007-07-20

Bis(ketenimines), in which the two heterocumulenic functions are placed in close proximity on a carbon skeleton to allow their mutual interaction, show a rich and not easily predictable chemistry. Intramolecular [2 + 2] or [4 + 2] cycloadditions are, respectively, observed when both ketenimine functions are supported on either ortho-benzylic or 2,2'-biphenylenic scaffolds. In addition, nitrogen-to-carbon [1,3] and [1,5] shifts of arylmethyl groups in N-arylmethyl-C,C-diphenyl ketenimines are also disclosed.

Raman spectroscopy of DNA-metal complexes. II. The thermal denaturation of DNA in the presence of Sr2+, Ba2+, Mg2+, Ca2+, Mn2+, Co2+, Ni2+, and Cd2+.

Science.gov (United States)

Duguid, J G; Bloomfield, V A; Benevides, J M; Thomas, G J

1995-12-01

Differential scanning calorimetry, laser Raman spectroscopy, optical densitometry, and pH potentiometry have been used to investigate DNA melting profiles in the presence of the chloride salts of Ba2+, Sr2+, Mg2+, Ca2+, Mn2+, Co2+, Ni2+, and Cd2+. Metal-DNA interactions have been observed for the molar ratio [M2+]/[PO2-] = 0.6 in aqueous solutions containing 5% by weight of 160 bp mononucleosomal calf thymus DNA. All of the alkaline earth metals, plus Mn2+, elevate the melting temperature of DNA (Tm > 75.5 degrees C), whereas the transition metals Co2+, Ni2+, and Cd2+ lower Tm. Calorimetric (delta Hcal) and van't Hoff (delta HVH) enthalpies of melting range from 6.2-8.7 kcal/mol bp and 75.6-188.6 kcal/mol cooperative unit, respectively, and entropies from 17.5 to 24.7 cal/K mol bp. The average number of base pairs in a cooperative melting unit () varied from 11.3 to 28.1. No dichotomy was observed between alkaline earth and transition DNA-metal complexes for any of the thermodynamic parameters other than their effects on Tm. These results complement Raman difference spectra, which reveal decreases in backbone order, base unstacking, distortion of glycosyl torsion angles, and rupture of hydrogen bonds, which occur after thermal denaturation. Raman difference spectroscopy shows that transition metals interact with the N7 atom of guanine in duplex DNA. A broader range of interaction sites with single-stranded DNA includes ionic phosphates, the N1 and N7 atoms of purines, and the N3 atom of pyrimidines. For alkaline earth metals, very little interaction was observed with duplex DNA, whereas spectra of single-stranded complexes are very similar to those of melted DNA without metal. However, difference spectra reveal some metal-specific perturbations at 1092 cm-1 (nPO2-), 1258 cm-1 (dC, dA), and 1668 cm-1 (nC==O, dNH2 dT, dG, dC). Increased spectral intensity could also be observed near 1335 cm-1 (dA, dG) for CaDNA. Optical densitometry, employed to detect DNA

Strain engineering of WS2, WSe2, and WTe2

KAUST Repository

Amin, Bin

2014-01-01

We perform first-principles calculations to investigate the structural, electronic, and vibrational properties of WS2, WSe2, and WTe2 monolayers, taking into account the strong spin orbit coupling. A transition from a direct to an indirect band gap is achieved for compressive strain of 1% for WS2, 1.5% for WSe2, and 2% for WTe 2, while the nature of the band gap remains direct in the case of tensile strain. The size of the band gap passes through a maximum under compressive strain and decreases monotonically under tensile strain. A strong spin splitting is found for the valence band in all three compounds, which is further enhanced by tensile strain. The mobility of the electrons grows along the series WS2 < WSe2 < WTe2. This journal is © the Partner Organisations 2014.

2-(2-Oxo-1,4-dihydro-2H-quinazolin-3-yl)- and 2-(2,2-dioxo-1,4-dihydro-2H-2lambda6-benzo[1,2,6]thiadiazin-3-yl)-N-hydroxy-acetamides as potent and selective peptide deformylase inhibitors.

Science.gov (United States)

Apfel, C; Banner, D W; Bur, D; Dietz, M; Hubschwerlen, C; Locher, H; Marlin, F; Masciadri, R; Pirson, W; Stalder, H

2001-06-07

Potent, selective, and structurally new inhibitors of the Fe(II) enzyme Escherichia coli peptide deformylase (PDF) were obtained by rational optimization of the weakly binding screening hit (5-chloro-2-oxo-1,4-dihydro-2H-quinazolin-3-yl)-acetic acid hydrazide (1). Three-dimensional structural information, gathered from Ni-PDF complexed with 1, suggested the preparation of two series of related hydroxamic acid analogues, 2-(2-oxo-1,4-dihydro-2H-quinazolin-3-yl)-N-hydroxy-acetamides (A) and 2-(2,2-dioxo-1,4-dihydro-2H-2lambda(6)-benzo[1,2,6]thiadiazin-3-yl)-N-hydroxy-acetamides (B), among which potent PDF inhibitors (37, 42, and 48) were identified. Moreover, two selected compounds, one from each series, 36 and 41, showed good selectivity for PDF over several endoproteases including matrix metalloproteases. However, these compounds showed only weak antibacterial activity.

Crystal structures of ZnCl2·2.5H2O, ZnCl2·3H2O and ZnCl2·4.5H2O

Directory of Open Access Journals (Sweden)

Erik Hennings

2014-12-01

Full Text Available The formation of different complexes in aqueous solutions is an important step in understanding the behavior of zinc chloride in water. The structure of concentrated ZnCl2 solutions is governed by coordination competition of Cl− and H2O around Zn2+. According to the solid–liquid phase diagram, the title compounds were crystallized below room temperature. The structure of ZnCl2·2.5H2O contains Zn2+ both in a tetrahedral coordination with Cl− and in an octahedral environment defined by five water molecules and one Cl− shared with the [ZnCl4]2− unit. Thus, these two different types of Zn2+ cations form isolated units with composition [Zn2Cl4(H2O5] (pentaaqua-μ-chlorido-trichloridodizinc. The trihydrate {hexaaquazinc tetrachloridozinc, [Zn(H2O6][ZnCl4]}, consists of three different Zn2+ cations, one of which is tetrahedrally coordinated by four Cl− anions. The two other Zn2+ cations are each located on an inversion centre and are octahedrally surrounded by water molecules. The [ZnCl4] tetrahedra and [Zn(H2O6] octahedra are arranged in alternating rows parallel to [001]. The structure of the 4.5-hydrate {hexaaquazinc tetrachloridozinc trihydrate, [Zn(H2O6][ZnCl4]·3H2O}, consists of isolated octahedral [Zn(H2O6] and tetrahedral [ZnCl4] units, as well as additional lattice water molecules. O—H...O hydrogen bonds between the water molecules as donor and ZnCl4 tetrahedra and water molecules as acceptor groups leads to the formation of a three-dimensional network in each of the three structures.

The europium(II) oxide halides Eu{sub 2}OBr{sub 2} and Eu{sub 2}OI{sub 2}; Die Europium(II)-Oxidhalogenide Eu{sub 2}OBr{sub 2} und Eu{sub 2}OI{sub 2}

Energy Technology Data Exchange (ETDEWEB)

Rudolph, Daniel; Schleid, Thomas [Stuttgart Univ. (Germany). Inst. fuer Anorganische Chemie

2017-07-01

The syntheses and crystal structures of the two isotypic europium(II) oxide halides Eu{sub 2}OBr{sub 2} and Eu{sub 2}OI{sub 2} are reported. They crystallize orthorhombically in the space group Ibam (Z=4; Eu{sub 2}OBr{sub 2}: a=709.86(5), b=1200.34(9), c=628.71(4) pm; Eu{sub 2}OI{sub 2}: a=739.78(5), b=1295.13(9), c=644.82(4) pm). The unit cell parameters presented here, and thus the interatomic distances of Eu{sub 2}OI{sub 2}, are significantly smaller than the ones reported in the literature, which is explained by the substitution of europium with larger barium cations due to the synthesis route described in the early study. Central building blocks of both crystal structures are trans-edge-connected [OEu{sub 4}]{sup 6+} tetrahedra forming straight {sup 1}{sub ∞}{[OEu"e_4_/_2]"2"+} chains running parallel to the [001] direction. Bundled like a hexagonal rod packing, their interaction is achieved by Br{sup -} or I{sup -} anions for charge compensation.

Synthesis, structure and magnetic behavior of a new three-dimensional Manganese phosphite-oxalate: [C2N2H10][Mn2II(OH2)2(HPO3)2(C2O4)

International Nuclear Information System (INIS)

Ramaswamy, Padmini; Mandal, Sukhendu; Natarajan, Srinivasan

2009-01-01

A novel manganese phosphite-oxalate, [C 2 N 2 H 10 ][Mn 2 II (OH 2 ) 2 (HPO 3 ) 2 (C 2 O 4 )] has been hydothermally synthesized and its structure determined by single-crystal X-ray diffraction. The structure consists of neutral manganese phosphite layers, [Mn(HPO 3 )] ∞ , formed by MnO 6 octahedra and HPO 3 units, cross-linked by the oxalate moieties. The organic cations occupy the middle of the 8-membered one-dimensional channels. Magnetic studies indicate weak antiferromagnetic interactions between the Mn 2+ ions. - Abstract: A new antiferromagnetic three-dimensional inorganic-organic hybrid compound, [C 2 N 2 H 10 ][Mn 2 II (OH 2 ) 2 (HPO 3 ) 2 (C 2 O 4 )] has been prepared hydrothermally. The compound has neutral manganese layers pillared by oxalate units. The neutral manganese layers are shown here. Display Omitted

Emission analysis of Tb3+ -and Sm3+ -ion-doped (Li2 O/Na2 O/K2 O) and (Li2 O + Na2 O/Li2 O + K2 O/K2 O + Na2 O)-modified borosilicate glasses.

Science.gov (United States)

Naveen Kumar Reddy, B; Sailaja, S; Thyagarajan, K; Jho, Young Dahl; Sudhakar Reddy, B

2018-05-01

Four series of borosilicate glasses modified by alkali oxides and doped with Tb 3+ and Sm 3+ ions were prepared using the conventional melt quenching technique, with the chemical composition 74.5B 2 O 3 + 10SiO 2 + 5MgO + R + 0.5(Tb 2 O 3 /Sm 2 O 3 ) [where R = 10(Li 2 O /Na 2 O/K 2 O) for series A and C, and R = 5(Li 2 O + Na 2 O/Li 2 O + K 2 O/K 2 O + Na 2 O) for series B and D]. The X-ray diffraction (XRD) patterns of all the prepared glasses indicate their amorphous nature. The spectroscopic properties of the prepared glasses were studied by optical absorption analysis, photoluminescence excitation (PLE) and photoluminescence (PL) analysis. A green emission corresponding to the 5 D 4 → 7 F 5 (543 nm) transition of the Tb 3+ ions was registered under excitation at 379 nm for series A and B glasses. The emission spectra of the Sm 3+ ions with the series C and D glasses showed strong reddish-orange emission at 600 nm ( 4 G 5/2 → 6 H 7/2 ) with an excitation wavelength λ exci = 404 nm ( 6 H 5/2 → 4 F 7/2 ). Furthermore, the change in the luminescence intensity with the addition of an alkali oxide and combinations of these alkali oxides to borosilicate glasses doped with Tb 3+ and Sm 3+ ions was studied to optimize the potential alkali-oxide-modified borosilicate glass. Copyright © 2017 John Wiley & Sons, Ltd.

Synthesis of 1-(2,3-dihydroxypropyl)-2-nitro-1H-imidazole-2-14C and N-(2-hydroxyethyl)-2-(2-nitro-1H-imidazol-1-YL-2-14C)acetamide

International Nuclear Information System (INIS)

Fong, M.T.; Leaffer, M.A.

1986-01-01

We have prepared the 14 C-labeled analogs of NSC 261036, 1-(2,3-dihydroxypropyl)-2-nitro-1H-imidazole-2- 14 C, and NSC 301467, N-(2-hydroxyethyl)-2-(2-nitro-1H-imidazol-1-yl-2- 14 C) acetamide, for pharmacological, drug distribution, and mechanisms of action studies. The latter is an analog designed for lower toxicity and improved properties. The former is a metabolite of, and appears to be less toxic than, misonidazole. (author)

Tris[2-(2H-indazol-2-ylethyl]amine

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Saúl Ovalle

2012-06-01

Full Text Available The title tertiary amine, C27H27N7, a potential tripodal ligand for coordination chemistry, crystallizes with the central N atom located on a threefold axis of a trigonal cell. The gauche conformation of the N(amime—CH2—CH2—N(indazole chain [torsion angle = −64.2 (2°] places the pendant 2H-indazole heterocycles surrounding the symmetry axis, affording a claw-like shaped molecule. Two symmetry-related indazole planes in the molecule make an acute angle of 60.39 (4°. The lone pair of the tertiary N atom is located inside the cavity, and should thus be inactive (as a ligand. In the crystal, neither significant π–π nor C—H...π interactions between molecules are found.

Diacylglycerol Acyltransferase-2 (DGAT2) and Monoacylglycerol Acyltransferase-2 (MGAT2) Interact to Promote Triacylglycerol Synthesis*

Science.gov (United States)

Jin, Youzhi; McFie, Pamela J.; Banman, Shanna L.; Brandt, Curtis; Stone, Scot J.

2014-01-01

Acyl CoA:1,2-diacylglycerol acyltransferase (DGAT)-2 is an integral membrane protein that catalyzes triacylglycerol (TG) synthesis using diacylglycerol and fatty acyl CoA as substrates. DGAT2 resides in the endoplasmic reticulum (ER), but when cells are incubated with fatty acids, DGAT2 interacts with lipid droplets presumably to catalyze localized TG synthesis for lipid droplet expansion. Previous studies have shown that DGAT2 interacts with proteins that synthesize its fatty acyl CoA substrates. In this study, we provide additional evidence that DGAT2 is present in a protein complex. Using a chemical cross-linker, disuccinimidyl suberate (DSS), we demonstrated that DGAT2 formed a dimer and was also part of a protein complex of ∼650 kDa, both in membranes and on lipid droplets. Using co-immunoprecipitation experiments and an in situ proximity ligation assay, we found that DGAT2 interacted with monoacylglycerol acyltransferase (MGAT)-2, an enzyme that catalyzes the synthesis of diacylglycerol. Deletion mutagenesis showed that the interaction with MGAT2 was dependent on the two transmembrane domains of DGAT2. No significant interaction of DGAT2 with lipin1, another enzyme that synthesizes diacylglycerol, could be detected. When co-expressed in cells, DGAT2 and MGAT2 co-localized in the ER and on lipid droplets. Co-expression also resulted in increased TG storage compared with expression of DGAT2 or MGAT2 alone. Incubating McArdle rat hepatoma RH7777 cells with 2-monoacylglycerol caused DGAT2 to translocate to lipid droplets. This also led to the formation of large cytosolic lipid droplets, characteristic of DGAT2, but not DGAT1, and indicated that DGAT2 can utilize monoacylglycerol-derived diacylglycerol. These findings suggest that the interaction of DGAT2 and MGAT2 serves to channel lipid substrates efficiently for TG biosynthesis. PMID:25164810

Structure and bonding of transition metal-boryl compounds. Theoretical study of [(PH3)2(CO)ClOs-BR2] and [(PH3)2(CO)2ClOs-BR2] (BR2 = BH2, BF2, B(OH)2, B(OCH=CHO), Bcat).

Science.gov (United States)

Giju, K T; Bickelhaupt, F M; Frenking, G

2000-10-16

Quantum chemical DFT calculations using the B3LYP functionals have been carried out for the electronically unsaturated 16 VE five-coordinate osmium boryl-complexes [(PH3)2(CO)ClOs-BR2] and the 18 VE six-coordinate complexes [(PH3)2(CO)2ClOs-BR2] with BR2 = BH2, BF2, B(OH)2, B(OHC=CHO), and Bcat (cat = catecholate O2C6H4). The bonding situation of the Os-BR2 bond was analyzed with the help of the NBO partitioning scheme. The Os-B bond dissociation energies of the 16 VE complexes are very high, and they do not change very much for the different boryl ligands. The 18 VE complexes have only slightly lower bond energies than the 16 VE species. The Os-B bond in both classes of compounds is provided by a covalent sigma-bond which is polarized toward osmium and by strong charge attraction. Os-->B pi-donation is not important for the Os-B binding interactions, except for the Os-BH2 complexes. The stability of the boryl complexes [Os]-BR2 comes mainly from BB pi-donation. The intraligand charge distribution of the BR2 group changes little when the Os-B bond is formed, except for BH2. The CO ligand in [(PH3)2(CO)2ClOs-BR2] which is trans to BR2 has a relatively weak bond to the osmium atom.

Preparation and luminescence properties of Eu2+-doped CaSi2O2-dN2+2/3d phosphors

International Nuclear Information System (INIS)

Gu Yunxin; Zhang Qinghong; Wang Hongzhi; Li Yaogang

2009-01-01

Eu 2+ -doped CaSi 2 O 2-d N 2+2/3d phosphors for white LED lamps were prepared by solid-state reaction, and the effects of heat-treatment conditions and the overall composition of host lattice on the optical properties have been discussed. Eu 2+ -doped CaSi 2 O 2-d N 2+2/3d displayed a single broad emission band peak at 540 nm, which could be assigned to the allowed transition of Eu 2+ from the lowest crystal field component of 4f 6 5d to 4f 7 ground-state level. The excitation band of samples, extending from UV to blue, is extremely wide, so the phosphors are suitable for white LED lamps in combination with a UV or blue LED dies. The highest PL intensity is found for the sample sintered at 1400 0 C. Moreover, the emission intensity decreases when N partially replaces O. A red shift of emission wavelength did not occur with increasing of the N content.

N-(2-Chlorophenyl-2-methylbenzamide

Directory of Open Access Journals (Sweden)

B. Thimme Gowda

2008-08-01

Full Text Available In the structure of the title compound (N2CP2MBA, C14H12ClNO, the conformations of the N—H and C=O bonds are trans to each other. Furthermore, the conformation of the N—H bond is syn to the ortho-chloro group in the aniline ring and the C=O bond is syn to the ortho-methyl substituent in the benzoyl ring, similar to what is observed in 2-chloro-N-(2-chlorophenylbenzamide and 2-methyl-N-phenylbenzamide. The amide group makes almost the same dihedral angles of 41.2 (14 and 42.2 (13° with the aniline and benzoyl rings, respectively, while the dihedral angle between the benzoyl and aniline rings is only 7.4 (3°. The molecules in N2CP2MBA are packed into chains through N—H...O hydrogen bonds.

Synthesis and X-ray crystal structure of (OsO(3)F(2))(2)2XeOF(4) and the Raman spectra of (OsO(3)F(2))(infinity), (OsO(3)F(2))(2), and (OsO(3)F(2))(2)2XeOF(4).

Science.gov (United States)

Hughes, Michael J; Mercier, Hélène P A; Schrobilgen, Gary J

2009-05-18

The adduct, (OsO(3)F(2))(2)2XeOF(4), was synthesized by dissolution of the infinite chain polymer, (OsO(3)F(2))(infinity), in XeOF(4) solvent at room temperature followed by removal of excess XeOF(4) under dynamic vacuum at 0 degrees C. Continued pumping at 0 degrees C resulted in removal of associated XeOF(4), yielding (OsO(3)F(2))(2), a new low-temperature phase of OsO(3)F(2). Upon standing at 25 degrees C for 1(1)/(2) h, (OsO(3)F(2))(2) underwent a phase transition to the known monoclinic phase, (OsO(3)F(2))(infinity). The title compounds, (OsO(3)F(2))(infinity), (OsO(3)F(2))(2), and (OsO(3)F(2))(2)2XeOF(4) have been characterized by low-temperature (-150 degrees C) Raman spectroscopy. Crystallization of (OsO(3)F(2))(2)2XeOF(4) from XeOF(4) solution at 0 degrees C yielded crystals suitable for X-ray structure determination. The structural unit contains the (OsO(3)F(2))(2) dimer in which the OsO(3)F(3) units are joined by two Os---F---Os bridges having fluorine bridge atoms that are equidistant from the osmium centers (2.117(5) and 2.107(4) A). The dimer coordinates to two XeOF(4) molecules through Os-F...Xe bridges in which the Xe...F distances (2.757(5) A) are significantly less than the sum of the Xe and F van der Waals radii (3.63 A). The (OsO(3)F(2))(2) dimer has C(i) symmetry in which each pseudo-octahedral OsO(3)F(3) unit has a facial arrangement of oxygen ligands with XeOF(4) molecules that are only slightly distorted from their gas-phase C(4v) symmetry. Quantum-chemical calculations using SVWN and B3LYP methods were employed to calculate the gas-phase geometries, natural bond orbital analyses, and vibrational frequencies of (OsO(3)F(2))(2), (OsO(3)F(2))(2)2XeOF(4), XeOF(4), OsO(2)F(4), and (mu-FOsO(3)F(2))(2)OsO(3)F(-) to aid in the assignment of the experimental vibrational frequencies of (OsO(3)F(2))(2), (OsO(3)F(2))(2)2XeOF(4), and (OsO(3)F(2))(infinity). The vibrational modes of the low-temperature polymeric phase, (OsO(3)F(2))(infinity), have been

First-principles analysis of MoS2/Ti2C and MoS2/Ti2CY2 (Y=F and OH) all-2D semiconductor/metal contacts

KAUST Repository

Gan, Liyong

2013-06-13

First-principles calculations are used to explore the geometry, bonding, and electronic properties of MoS2/Ti2C and MoS2/Ti2CY2 (Y = F and OH) semiconductor/metal contacts. The structure of the interfaces is determined. Strong chemical bonds formed at the MoS2/Ti2C interface result in additional states next to the Fermi level, which extend over the three atomic layers of MoS2 and induce a metallic character. The interaction in MoS2/Ti2CY2, on the other hand, is weak and not sensitive to the specific geometry, and the semiconducting nature thus is preserved. The energy level alignment implies weak and strong n-type doping of MoS2 in MoS2/Ti2CF2 and MoS2/Ti2C(OH)2, respectively. The corresponding n-type Schottky barrier heights are 0.85 and 0.26 eV. We show that the MoS2/Ti2CF2 interface is close to the Schottky limit. At the MoS2/Ti2C(OH)2 interface, we find that a strong dipole due to charge rearrangement induces the Schottky barrier. The present interfaces are well suited for application in all-two-dimensional devices.

First-principles analysis of MoS2/Ti2C and MoS2/Ti2CY2 (Y=F and OH) all-2D semiconductor/metal contacts

KAUST Repository

Gan, Liyong; Huang, Dan; Schwingenschlö gl, Udo; Zhao, Yu-Jun

2013-01-01

First-principles calculations are used to explore the geometry, bonding, and electronic properties of MoS2/Ti2C and MoS2/Ti2CY2 (Y = F and OH) semiconductor/metal contacts. The structure of the interfaces is determined. Strong chemical bonds formed at the MoS2/Ti2C interface result in additional states next to the Fermi level, which extend over the three atomic layers of MoS2 and induce a metallic character. The interaction in MoS2/Ti2CY2, on the other hand, is weak and not sensitive to the specific geometry, and the semiconducting nature thus is preserved. The energy level alignment implies weak and strong n-type doping of MoS2 in MoS2/Ti2CF2 and MoS2/Ti2C(OH)2, respectively. The corresponding n-type Schottky barrier heights are 0.85 and 0.26 eV. We show that the MoS2/Ti2CF2 interface is close to the Schottky limit. At the MoS2/Ti2C(OH)2 interface, we find that a strong dipole due to charge rearrangement induces the Schottky barrier. The present interfaces are well suited for application in all-two-dimensional devices.

System of Sr(NO2)2-Sr(OH)2-H2O at 25 deg C

International Nuclear Information System (INIS)

Popova, T.B.; Berdyukova, V.A.; Khutsistova, F.M.

1990-01-01

Sr(NO 2 ) 2 -Sr(OH) 2 -H 2 O system was investigated by the methods of solubility, density, viscosity, electric conductivity and refractometry. It was established that its compoments form the compound 4Sr(NO 2 ) 2 xSr(OH) 2 x8H 2 O. The compound was separated from solution; its density, decomposition temperature were determined; IR spectra and X-ray patterns of prepared and initial compounds were obtained

Electron excitation cross sections for the 2s(2)2p(3)4S(O) -- 2s(2)2p(3)2D(O) (forbidden) and 4S(O) -- 2s2p(4) 4P (resonance) transitions in O II

Science.gov (United States)

Zuo, M.; Smith, Steven J.; Chutjian, A.; Williams, I. D.; Tayal, S. S.; Mclaughlin, Brendan M.

1995-01-01

Experimental and theoretical excitation cross sections are reported for the first forbidden transition 4S(O) -- 2S(2)2p(3) 2D(O) (lambda-lambda 3726, 3729) and the first allowed (resonance) transition 4S(O) -- 2s2p(4) 4P(lambda-833) in O II. Use is made of electron energy loss and merged-beams methods. The electron energy range covered is 3.33 (threshold) to 15 eV for the S -- D transition, and 14.9 (threshold) to 40 eV for the S -- P transition. Care was taken to assess and minimize the metastable fraction of the O II beam. An electron mirror was designed and tested to reflect inelastically backscattered electrons into the forward direction to account for the full range of polar scattering angles. Comparisons are made between present experiments and 11-state R-matrix calculations. Calculations are also presented for the 4S(O) -- 2s(2)2p(3)2P(O) (lambda-2470) transition.

Dentritic Carbosilanes Containing Silicon-Bonded 1-[C6H2(CH2NMe2)2-3,5-Li-4] or 1-[C6H3(CH2NMe2)-4-Li-3] Mono-and Bis(amino)aryllithium End Groups: Structure of {[CH2SiMe2C6H3(CH2NMe2)-4-Li-3]2}2