Radiation degradation of cellulose

Leonhardt, Jürgen; Arnold, G. W.; Baer, M.; Langguth, H.; Gey, Manfred H.; Hubert, Sharon

doi:10.1016/0146-5724(85)90170-0

Cited by 10 publications

(10 citation statements)

References 2 publications

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“…The efficiency of these two types of reactions depends mainly on the polymer structure and radiation dose . The radiation effects on the physical, chemical, and biological properties of other polymers have been studied extensively. − Several studies 5,7,10,11 have shown that the irradiation of cotton cellulose deteriorated the mechanical parameters due to the chain scission reaction within the cellulose molecules. Takács and co-workers − have reported that the high-energy radiation cause a decrease in the degree of polymerization and an increase in the carbonyl content of cotton cellulose.…”

Section: Introductionmentioning

confidence: 99%

γ-Radiation Induced Changes in the Physical and Chemical Properties of Lignocellulose

2006

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gamma-radiation induced effects on the physical and chemical properties of natural lignocellulose (jute) polymer were investigated. Samples were irradiated to required total doses at a particular dose rate. The changes in the parameters such as the tensile strength, elongation at break, and work done at rupture for the lignocellulose samples on irradiation with the gamma-rays from a cobalt-60 source were measured. The mechanical properties were found to have nonlinear relations with the radiation doses. The chemical stability of irradiated fibers was found to degrade progressively with the increase of radiation dose. Additionally, other chemical changes of the samples due to exposure to high-energy radiation were also investigated using fluorescence and infrared spectroscopic analysis. Differential scanning calorimetry and thermogravimetric studies showed a significant reduction in thermal stability. The wide-angle X-ray diffraction study showed that structural changes of cellulose appeared due to the radiation-induced chemical reaction of lignocellulose.

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Section: Introductionmentioning

confidence: 99%

γ-Radiation Induced Changes in the Physical and Chemical Properties of Lignocellulose

2006

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“…However, it is thought that H · and · OH radicals formed by radiolysis during the irradiation of water accelerate the molecular chain scission of alginate25 because polysaccharides are typical degradable materials under ionizing irradiation according to the reduction of the molecular weight 26. A reaction between the aforementioned free radicals and alginate molecules leads to rapid degradation of alginate in an aqueous solution.…”

Section: Resultsmentioning

confidence: 99%

Both the body and brain benefit from exercise: Potential win‐win for Parkinson's disease patients

Weintraub¹,

Morgan²

2011

Movement Disorders

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Review Of: Erickson KI, Voss MW, Prakash RS, et al. Exercise training increases size of hippocampus and improves memory. Proc Natl Acad Sci U S A. 2011;108:3017-3022 and The motor symptoms of Parkinson's disease (PD) lead to functional impairment and place patients at increased risk of significant adverse outcomes (eg, falls and hip fractures). Reviews of clinical trials have concluded that exercise in PD is beneficial for physical functioning, health-related quality of life, strength, postural stability, balance, and gait speed.1,2 A recent comparative controlled study found that PD patients undergoing exercise training with the LSVTV R BIG technique had approximately 5 points of improvement in their UPDRS motor score after 16 weeks.3 This benefit was superior to 2 other groups that were walking or performing a self-directed home exercise program (their UPDRS motor scores actually worsened slightly).It is not clear if exercise training in PD has benefits that extend beyond improvement in motor function, however. This is particularly relevant in PD, a disease with frequently disabling nonmotor symptoms, including dementia (PDD) 4 and mild cognitive impairment (PD-MCI). 5 The neural substrate of cognitive decline in PD appears complex, but hippocampal atrophy has been associated with cognitive decline in PD patients. [6][7][8] Erickson et al 9 recently conducted a single-blind, randomized, controlled trial of exercise training in 120 healthy, older adults. The investigators predicted that 1 year of moderateintensity aerobic exercise (ie, walking with a target heart rate zone of 60%-75% of maximum heart rate reserve) 3 days per week would increase hippocampal size, which in turn would be associated with increased brain-derived neurotrophic factor (BDNF) and improved spatial memory. This hypothesis was based on previous preclinical and clinical research demonstrating that exercise improves cognitive abilities and hippocampal cell proliferation and survival, which may in part be mediated by increased BDNF production.The results of the study were compelling and can be summarized as follows: (1) The aerobic exercise group had an increase in bilateral hippocampal volumes (specifically the anterior hippocampus) over 1 year, whereas the control group had a decrease in hippocampal volume (consistent with normal aging), and the difference was statistically significant. No such changes were seen in the control brain regions. (2) In the entire sample, improvement over time in aerobic fitness (increase in VO 2 max) was positively correlated with increase in hippocampal volume. (3) In the LSVTV R BIG exercise group, increases in serum BDNF were positively correlated with increased hippocampal volume, specifically the anterior hippocampus. (4) In the exercise group, increased hippocampal volume was positively correlated with improvements in spatial memory performance.Research suggests that exercise training offers substantial motor benefits for PD patients, and ongoing randomized clinical trials are assessing its impact on no...

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“…With increasing the irradiation dose to 30kGy, the number average molecular wt reduced to 9.9x10 3 , 9.2x10 3 and 1.2x10 4 (Da), respectively. Polysaccharides are typical degradable materials under ionizing radiation which undergo degradation reactions through the β-(1-4) glycosidic bond cleavage resulting in the reduction of its average molecular wt (Leonhardt et al, 1985). UV-Vis.…”

Section: Resultsmentioning

confidence: 99%

Comparative Study on the Antioxidative Properties of Some Natural Polymers Degraded by γ-rays

2011

Egypt. J. Rad.Sci.

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ADIATION induced degradation of chitosan, Na-alginate and carrageenan was carried out to prepare oligosaccharides with different molecular wt. Structural and average molecular wt changes of such oligosaccharides were determined by gel permeation chromatography (GPC), Fourier transform infra-red (FT-IR) and ultraviolet (UV-Vis.) spectroscopy. FT-IR and UV-Vis. studies revealed that during radiation degradation process, the main polysaccharide chain structure was almost remained. Comparative study on the antioxidative properties of chitosan, Na-alginate and carrageenan oligosaccharides of different molecular wt was investigated. Radical mediated lipid peroxidation inhibition, scavenging effect on 1,1-diphenyl-2picrylhydrazyl (DPPH) radicals, reducing power and the ferrous ion chelating activity assays were used to evaluate the antioxidant activity. The irradiation process enhances the antioxidant activity of such polysaccharides. The lower the molecular wt of oligosaccharides is the higher the antioxidant activity. The antioxidant activity of irradiated chitosan was higher than Na-alginate and carrageenan. At 30 kGy, the inhibition concentration (IC 50 ) on DPPH radicals was 0.154, 0.359, 0.438 and 0.140 mg/ml for chitosan, Na-alginate carrageenan, and ascorbic acid, respectively.

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Radiation degradation of cellulose

Cited by 10 publications

References 2 publications

γ-Radiation Induced Changes in the Physical and Chemical Properties of Lignocellulose

γ-Radiation Induced Changes in the Physical and Chemical Properties of Lignocellulose

Both the body and brain benefit from exercise: Potential win‐win for Parkinson's disease patients

Comparative Study on the Antioxidative Properties of Some Natural Polymers Degraded by γ-rays

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