scholarly journals Synthesis of Brominated Polyethylene by Copolymerization of Ethylene with ω–bromoalkene Catalyzed by a Metallocene and Methylaluminoxane System

Catalysts ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 660
Author(s):  
Toda ◽  
Miura ◽  
Miya ◽  
Takenaka

The metallocene-catalyzed copolymerization of ethylene and 11–bromo–1–undecene was carried out to synthesize brominated polyethylene (PE). A modified methylaluminoxane (MMAO) solution was used as a cocatalyst and rac–Et(H4Ind)2ZrCl2 as a catalyst. The copolymerization showed a high activity and afforded the copolymer with a 11-bromo-1-undecene incorporation ranging from 1.0 to 4.3 mol%. When using a dried methylaluminoxane (dMAO) as a cocatalyst, the incorporation ratio of 11-bromo-1-undecene increased remarkably to 25.2 mol%. It was demonstrated that the type of MAO used as a cocatalyst affects the composition of the ethylene/11-bromo-1-undecene copolymer without changing the structure of the catalytic complex.

2001 ◽  
Vol 40 (06) ◽  
pp. 215-220 ◽  
Author(s):  
S. Bielack ◽  
S. Flege ◽  
J. Eckardt ◽  
J. Sciuk ◽  
H. Jürgens ◽  
...  

Summary Purpose: Despite highly efficacious chemotherapy, patients with osteosarcomas still have a poor prognosis if adequate surgical control cannot be obtained. These patients may benefit from therapy with radiolabeled phosphonates. Patients and Methods: Six patients (three male, three female; seven to 41 years) with unresectable primary osteosarcoma (n = 3) or unresectable recurrent sites of osteosarcomas (n = 3) were treated with high-activity of Sm-153-EDTMP (150 MBq/kg BW). In all patients autologous peripheral blood stem cells had been collected before Sm-153-EDTMP therapy. Results: No immediate adverse reactions were observed in the patients. In one patient bone pain increased during the first 48 hrs after therapy. Three patients received pain relief. Autologous peripheral blood stem cell reinfusion was performed on day +12 to +27 in all patients to overcome potentially irreversible damage to the hematopoietic stem cells. In three patient external radiotherapy of the primary tumor site was performed after Sm-153-EDTMP therapy and in two of them polychemotherapy was continued. Thirty-six months later one of these patients is still free of progression. Two further patients are still alive. However, they have developed new metastases. The three patients who had no accompanying external radiotherapy, all died of disease progression five to 20 months after therapy. Conclusion: These preliminary results show that high-dose Sm-153-EDTMP therapy is feasible and warrants further evaluation of efficacy. The combination with external radiation and polychemotherapy seems to be most promising. Although osteosarcoma is believed to be relatively radioresistant, the total focal dose achieved may delay local progression or even achieve permanent local tumor control in patients with surgically inaccessible primary or relapsing tumors.


1975 ◽  
Vol 34 (02) ◽  
pp. 409-418 ◽  
Author(s):  
I. M Nilsson ◽  
S.-E Bergentz ◽  
U Hedner ◽  
K Kullenberg

SummaryGastric juice from 15 normals, 20 patients with gastric ulcer and 4 patients with erosive haemorrhagic gastroduodenitis was investigated in respect of its activity on unheated and heated fibrin plates and its content of FDP and plasminogen or plasmin with immunochemical methods. Gastric juice from normals showed no activity on unheated and heated fibrin plates, and no FDP or plasminogen could be demonstrated. In the patients with gastric ulcer the gastric juice showed little or no fibrinolytic activity on fibrin plates except in 2, who had regurgitation of duodenal juice and neutral pH of the juice. These patients had equally high activity on heated as on unheated plates and no plasmin could be demonstrated. It was shown that this activity was not due to fibrinolysis, but to non-specific proteolytic activity (probably trypsin). The patients with erosive haemorrhagic gastroduodenitis exhibited quite a different picture. The gastric juice from these patients showed extremely high activity on fibrin plates, the activity was higher on unheated than on heated plates. The activity was inhibited in vitro by addition of EACA and in vivo after administration of AMCA. The occurrence of plasmin could be demonstrated directly immunologically in the gastric juice. By comparison of plasmin and trypsin in various assays it could further be proved that the gastric juice in these cases contained plasminogen activator and plasmin. The patients with erosive haemorrhagic gastroduodenitis showed no increase in fibrinolysis in the blood, but low values for plasminogen and α2M, and the serum contained FDP. These findings in the blood and gastric juice were interpreted as signs of local fibrinolysis in the stomach and duodenum. There is reason to assume that this gastric fibrinolysis contributes substantially to the bleeding tendency. The effect of administration of AMCA on fibrinolytic activity and the haemorrhage lends support to the assumption of such a mechanism.


1979 ◽  
Vol 42 (05) ◽  
pp. 1452-1459 ◽  
Author(s):  
Robert H Yue ◽  
Toby Starr ◽  
Menard M Gertler

SummaryCommercial porcine heparin can be separated into three distinct subtractions by using DEAE-cellulose chromatography and a stepped salt gradient. Gram quantities of heparin can be fractionated by this technique. All three heparin subtractions can accelerate the inhibition of thrombin by antithrombin III with different efficiency. The specific activities of the high activity heparin, intermediate activity heparin and low activity heparin are 228 units/mg, 142 units/mg and 95 units/mg, respectively. Both the uronic acid content and the quantity of N-SO4 for all three heparin subfractions have been evaluated. The high activity heparin has the lowest uronic acid and N-SO4 content. The successful separation of commercial heparin into three distinct subfractions by means of ion-exchange chromatography suggests that the net charge on these three heparin components will serve as a model system in the elucidation of the structure and activity relationship to the biological function of heparin.


2019 ◽  
Author(s):  
Caleb Karmel ◽  
Zhewei Chen ◽  
John Hartwig

We report a new system for the silylation of aryl C-H bonds. The combination of [Ir(cod)(OMe)]<sub>2</sub> and 2,9-Me<sub>2</sub>-phenanthroline (2,9-Me<sub>2</sub>phen) catalyzes the silylation of arenes at lower temperatures and with faster rates than those reported previously, when the hydrogen byproduct is removed, and with high functional group tolerance and regioselectivity. Inhibition of reactions by the H<sub>2</sub> byproduct is shown to limit the silylation of aryl C-H bonds in the presence of the most active catalysts, thereby masking their high activity. Analysis of initial rates uncovered the high reactivity of the catalyst containing the sterically hindered 2,9-Me<sub>2</sub>phen ligand but accompanying rapid inhibition by hydrogen. With this catalyst, under a flow of nitrogen to remove hydrogen, electron-rich arenes, including those containing sensitive functional groups, undergo silylation in high yield for the first time, and arenes that underwent silylation with prior catalysts react over much shorter times with lower catalyst loadings. The synthetic value of this methodology is demonstrated by the preparation of key intermediates in the synthesis of medicinally important compounds in concise sequences comprising silylation and functionalization. Mechanistic studies demonstrate that the cleavage of the aryl C-H bond is reversible and that the higher rates observed with the 2,9-Me<sub>2</sub>phen ligand is due to a more thermodynamically favorable oxidative addition of aryl C-H bonds.


2013 ◽  
pp. 133-135
Author(s):  
L. G. Naumova ◽  
E. Z. Baisheva ◽  
V. B. Martynenko

Bryansk syntaxonomic center (Mirkin, Ermakov, 2010), which includes a group of researchers, students by prof. Bulahov A. D., characterized by high activity. Peer-reviewed monograph summarizes studies of the vegetation of the Bryansk region in the context of the choice of subject matter. In the text of the monograph a brief "Foreword", Chapter 2 theoretical and 3 parts, which is characterized by rare, reference and moss vegetation communities.


Edupedia ◽  
2019 ◽  
Vol 3 (2) ◽  
pp. 67-77
Author(s):  
Farhatin Masrurah ◽  
Khulusinniyah Khulusinniyah

The first five years of a children’s age is the period of rapid growth with physical and motor development. Those process will develop well if stimulated continuously. Early childhood always identic with high activity requires the opportunity to express their abilities. Therefore playing method is very urgent inchildren’s gross motor skills and fine motor skills development through a variety of playing activities both indoors and outdoors. Playing is an activity that cannot be separated from early childhood’s world. All playing activities will be carried out happily. By the same token learning by playing will be done happily without any sense of being forced or oppressed.


2013 ◽  
Vol 19 (3) ◽  
pp. 523-527 ◽  
Author(s):  
Miaomiao LIU ◽  
Juan FENG ◽  
Hongbo LIU ◽  
Xiaolan YANG ◽  
Liping FENG ◽  
...  

1983 ◽  
Vol 48 (10) ◽  
pp. 2924-2936 ◽  
Author(s):  
Karel Mach ◽  
Lidmila Petrusová ◽  
Helena Antropiusová ◽  
Vladimír Hanuš ◽  
František Tureček ◽  
...  

μ-(η5 : η5-Fulvalene)-di-μ-hydrido-bis(η5-cyclopentadienyltitanium) and μ-(η5 : η5-fulvalene)-μ-chloro-μ-hydrido-bis(cyclopentadienyltitanium) form a thermally stable complex which catalyzes the intermolecular hydrogen transfer in unsaturated hydrocarbons, in addition to isomerizations and cyclizations. Cyclic hydrocarbons disproportionate under catalysis to saturated and aromatic hydrocarbons, while linear olefins yield predominantly linear alkanes and high molecular weight tar. The catalyst enables the hydrocarbon system to approach the thermodynamic equilibrium through a series of substitution reactions between alkyl- and allyltitanocene-like species and olefins and dienes. The catalytic complex was characterized by UV and ESR spectra. About one half of overall titanium content could be converted to mononuclear η3-allyltitanocene-like species, stable up to 400 °C. This exceptional thermal stability is ascribed to a firmly bound allyl containing ligand.


2010 ◽  
Vol 50 (4) ◽  
pp. 220
Author(s):  
Nadia Dwi Insani ◽  
Sukman Tulus Putra ◽  
Agus Firmansyah

Background Cardiovascular diseases remain the leading cause of death worldwide. Atherosclerotic process increases rapidly during adolescence. Physical activity is considered important in this period to modify cardiovascular risk factors, thus preventing disease in the future.Objective To determine whether different physical activity status in adolescence can influence body mass index (BMBMI), waist-to-hip ratio, blood pressure (BP), and blood lipid profile.Methods This was a cross-sectional descriptive study, conducted from December 2009 to January 2010. Adolescents who fulfilled the study criteria were classified into high and low physical activity category. Further examination including body mass index, waist-to-hip ratio, blood pressure, and blood lipid profile were performed.Results Adolescents with high physical activity had higher, but statistically insignificant, BMBMI compared to adolescents in the P=0.493] and significantly lower waist-to-hip ratio [0.80 (range 0.73-0.9) vs.. 0.82 (range 0.7-0.9), P=0.019]. Difference in BP was not statistically significant between both groups [diastolic BP (70 (range 60-90) mmHg vs. 70 (range 60-90) mmHg, P=0.148; systolic BP 100 (range 90-130) mmHg vs. 100 (range 90-140) mmHg, P=0.228)]. Blood lipid examination in the high activity group showed significantly higher HDL cholesterol and lower triglyceride compared to the low activity group [HDL 59.8 (SD 11.8) mg/dL vs. 54.7 (SD 8.9) mg/dL; p=0.044; triglyceride: 60 (range 32-203) mmHg vs. 82 (range 37-198) mmHg, P=0.014]. Total and LDL cholesterol [total cholesterol 169.8 (SD 28.6) mmHg vs. 181.2 (SD 30.8) mmHg, P=0.107; LDL 103.6 (SD 26.8) mmHg vs. 114.1 (SD 27.3) mmHg, P=0.100] were lower in the high activity group but not statistically different in both groups.Conclusions Adolescents with high physical activity show less cardiovascular risk factors compared to those in the low physical activity group.


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