scholarly journals Polymer Chain Mobility under Shear—A Rheo-NMR Investigation

Polymers ◽  
2018 ◽  
Vol 10 (11) ◽  
pp. 1231
Author(s):  
Brigitte Wiesner ◽  
Benjamin Kohn ◽  
Mandy Mende ◽  
Ulrich Scheler
Keyword(s):  
Molecular Weight ◽  
Nuclear Magnetic Resonance ◽  
Polymer Chain ◽  
Exponential Decay ◽  
High Weight ◽  
Low Molecular Weight ◽  
Chain Segment ◽  
Chain Mobility ◽  
Two Samples ◽  
The Impact

The local dynamics in polymer melts and the impact of external shear in a Couette geometry have been investigated using rheological nuclear magnetic resonance (NMR). The spin-spin relaxation time, T2, which is sensitive to chain-segment motion, has been measured as a function of shear rate for two samples of poly(dimethylsiloxane). For the low-molecular-weight sample, a mono-exponential decay is observed, which becomes slightly faster with shear, indicating restrictions of the polymer chain motion. For the high-weight sample, a much faster bi-exponential decay is observed, indicative of entanglements. Both components in this decay become longer with shear. This implies that the free polymer segments between entanglements become effectively longer as a result of shear.

Microporous Bio-Membrane Materials Based on High Molecular Weight Polylactide and Low Molecular Weight Poly(ethylene glycol)

2012 ◽  
Vol 567 ◽  
pp. 123-126
Author(s):  
Teng Fei Shen ◽  
Man Geng Lu ◽  
Li Yan Liang
Keyword(s):  
Molecular Weight ◽  
Ethylene Glycol ◽  
High Weight ◽  
Low Molecular Weight ◽  
Poly Ethylene Glycol ◽  
Degradation Rates ◽  
Degradation Behaviors ◽  
The Mean ◽  
Poly Ethylene ◽  
Lower Glass Transition Temperature

In this work, microporous membrane biomaterials based on high weight molecular polylactide (PLA) and low molecular weight poly(ethylene glycol) (PEG) using rapid solvent evaporation method were prepared and investigated. The effect of PEG segments added on the thermal and degradation behaviors was studied. According to the results, produced PLA/PEG biomaterial has lower glass transition temperature (Tg)in comparison with neat PLA. It was also found that the degradation rates of the PLA/PEG biomaterials were significantly increased with adding of PEG, which explained by increasing hydrophilic groups. For better porous fixation, CL-blocked polyisocyanate (CL-bp), which was synthesized from reaction of isophorone diisocyanate (IPDI) with dimethylol propionic acid (DMPA) and Trimethylolpropane (TMP) followed by addition of caprolactam (CL), were introduced. The microporous forms were observed by the scanning electron microscope (SEM), which showed the mean diameters of prepared PLA/PEG microporous were around 10μm.

scholarly journals Changes in Protein Composition in the Grain and Malt after Fusarium Infection Dependently of Wheat Resistance

Pathogens ◽  
2019 ◽  
Vol 8 (3) ◽  
pp. 112 ◽  
Author(s):  
Spanic ◽  
Horvat ◽  
Drezner ◽  
Zdunic
Keyword(s):  
Molecular Weight ◽  
Grain Yield ◽  
Susceptible Variety ◽  
Resistant Variety ◽  
Low Molecular Weight ◽  
Protein Distribution ◽  
Glutenin Subunits ◽  
Wheat Grains ◽  
Fusarium Infection ◽  
The Impact

The grain yield, as well as the quality and safety of the wheat grains and corresponding malt can be compromised by Fusarium spp. infection. The protein content of the grain affects the chemical composition and enzyme levels of the finished malt. The malting industry demands varieties with good malting and brewing performance, as well as good agronomic performance and disease resistance. The best method of disease control is breeding and selection for resistant varieties. Due to higher requirements for malting wheat worldwide, the goal of this investigation was to explore changes in protein distribution in wheat grains and corresponding malt, which are under higher pressure of Fusarium head blight (FHB) infestation in field conditions. The present study provides new knowledge on the impact of the FHB on the distribution of protein components of naturally Fusarium-infected (control) and Fusarium-inoculated wheat varieties in the grain and the corresponding malt in two consecutive years (2015/2016 and 2016/2017). The results showed that Fusarium infection of the susceptible variety Golubica, decreased total glutenins (5.9%), and both high and low molecular weight glutenin subunits (2.5% and 3.5%, respectively) in wheat grains, compared to control, in 2016. In contrast, gliadins and α-gliadins increased significantly (+7.6% and +5.1%, respectively) in the same variety. Wheat grains of the more resistant variety Vulkan showed an increase of the total glutenins content (+4.3%), and of high and of low molecular weight glutenin subunits (+1.2% and +3.2%, respectively) after Fusarium-inoculation, compared to naturally infected grains in 2016. Susceptible variety Golubica increased total glutenins (+9.1%), and both high and low molecular weight glutenin subunits (+3.5% and +5.6%, respectively) after Fusarium-inoculation in wheat malt, compared to naturally infected malt in 2016. In 2017, when disease pressure was higher than in 2016, there was a tendency in all varieties to increase gliadins and its sub fractions after malting, and to decrease glutenins and its sub fractions in Fusarium-inoculated treatment. In conclusion, FHB dramatically depressed grain yield (up to 37%) and quality (glutenins and high molecular weight subunits) in the susceptible Fusarium variety, which makes it inconvenient for malting.

scholarly journals Low Molecular Weight Procyanidins from Grape Seeds Enhance the Impact of 5-Fluorouracil Chemotherapy on Caco-2 Human Colon Cancer Cells

PLoS ONE ◽  
2014 ◽  
Vol 9 (6) ◽  
pp. e98921 ◽  
Author(s):  
Ker Y. Cheah ◽  
Gordon S. Howarth ◽  
Keren A. Bindon ◽  
James A. Kennedy ◽  
Susan E. P. Bastian
Keyword(s):  
Molecular Weight ◽  
Colon Cancer ◽  
Cancer Cells ◽  
Human Colon ◽  
Low Molecular Weight ◽  
Colon Cancer Cells ◽  
Grape Seeds ◽  
Human Colon Cancer ◽  
The Impact ◽  
Human Colon Cancer Cells

Randomized Phase II Trial of Docetaxel Plus Thalidomide in Androgen-Independent Prostate Cancer

2004 ◽  
Vol 22 (13) ◽  
pp. 2532-2539 ◽  
Author(s):  
William L. Dahut ◽  
James L. Gulley ◽  
Philip M. Arlen ◽  
Yinong Liu ◽  
Katherine M. Fedenko ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Molecular Weight ◽  
Phase Ii ◽  
Low Molecular Weight Heparin ◽  
Phase Ii Trial ◽  
Low Molecular Weight ◽  
Randomized Phase Ii ◽  
The Impact ◽  
Docetaxel Group ◽  
Androgen Independent

Purpose Both docetaxel and thalidomide have demonstrated activity in androgen-independent prostate cancer (AIPC). We compared the efficacy of docetaxel to docetaxel plus thalidomide in patients with AIPC. Methods Seventy-five patients with chemotherapy-naïve metastatic AIPC were randomly assigned to receive either docetaxel 30 mg/m2 intravenously every week for 3 consecutive weeks, followed by a 1-week rest period (n = 25); or docetaxel at the same dose and schedule, plus thalidomide 200 mg orally each day (n = 50). Prostate-specific antigen (PSA) consensus criteria and radiographic scans were used to determine the proportion of patients with a PSA decline, and time to progression. Results After a median potential follow-up time of 26.4 months, the proportion of patients with a greater than 50% decline in PSA was higher in the docetaxel/thalidomide group (53% in the combined group, 37% in docetaxel-alone arm). The median progression-free survival in the docetaxel group was 3.7 months and 5.9 months in the combined group (P = .32). At 18 months, overall survival in the docetaxel group was 42.9% and 68.2% in the combined group. Toxicities in both groups were manageable after administration of prophylactic low-molecular-weight heparin in the combination group. Conclusion In this randomized phase II trial, the addition of thalidomide to docetaxel resulted in an encouraging PSA decline rate and overall median survival rate in patients with metastatic AIPC. After the prophylactic low-molecular-weight heparin was instituted to prevent venous thromboses, the combination regimen was well tolerated. Larger randomized trials are warranted to assess the impact of this combination.

scholarly journals Biologically active ion exchange (BIEX) for NOM removal and membrane fouling prevention

2017 ◽  
Vol 17 (4) ◽  
pp. 1178-1184 ◽  
Author(s):  
M. Schulz ◽  
J. Winter ◽  
H. Wray ◽  
B. Barbeau ◽  
P. Bérubé
Keyword(s):  
Molecular Weight ◽  
Biological Activity ◽  
Ion Exchange ◽  
Membrane Fouling ◽  
Building Blocks ◽  
Biologically Active ◽  
Low Molecular Weight ◽  
Effective Removal ◽  
Pre Treatment ◽  
The Impact

The natural organic matter (NOM) removal efficiency and regeneration behavior of ion-exchange filters with promoted biological activity (BIEX) was compared to operation where biological activity was suppressed (i.e. abiotic conditions). The impact of BIEX pre-treatment on fouling in subsequent ultrafiltration was also investigated. Biological operation enhanced NOM removal by approximately 50% due to an additional degradation of smaller humic substances, building blocks and low molecular weight acids. Promotion of biological activity significantly increased the time to breakthrough of the filters and, therefore, is expected to lower the regeneration frequency as well as the amount of regenerate of which to dispose. Pre-treatment using BIEX filters resulted in a significant decrease in total and irreversible fouling during subsequent ultrafiltration. The decrease was attributed to the effective removal of medium and low molecular weight NOM fractions. The results indicate that BIEX filtration is a robust, affordable and easy-to-operate pre-treatment approach to minimize fouling in ultrafiltration systems and enhance the quality of the produced permeate.

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