Effects of pH on the Morphological Structures and Release Properties in Chitosan Microspheres

With an attempt to expand the versatilities and applications in chitosan microspheres, chitosan were first converted into micro-droplets by using a high voltage electrostatic field system, and then treated with Na5P3O10/NaOH solution of volume ratio of 17/3, 19/1, 1/0 (pure Na5P3O10) or 0/1 (pure NaOH) to fabricate chitosan microsphere. By varying the pH values of these reacting agents, distinct morphological structures and properties of chitosan microspheres were further be changed. Chitosan microsphere prepared in this study exhibited a good spherical shape and was in a range of 185.8 ± 13.8 μm to 380.9 ± 11.5 μm in diameter. The size of chitosan microspheres varied by treating with various pH values of these reaction reagents. The prepared chitosan microspheres upon treatment with pH 7 of various ratios Na5P3O10/NaOH solution, all exhibited a shrunken surface morphological structure. This densely shrunken structure of microspheres yielded a stronger mechanical strength and a slower release rate of drug (5-FU), no matter what the ratios of Na5P3O10/NaOH solution was used. From the data of FTIR analyses, the protonated amino peak of NH3+ at around 1562 cm−1 has decreased significantly after treated with various pH values of these reaction reagents. It could be attributed to the linkage between phosphoric and ammonium ion of the protonated chitosan molecules. Besides, another boarder absorption at about 3366cm−1 of treated chitosan microspheres (under the employed range of pH values), which represented the hydrogen bonding was enhanced as compare with the pure chitosan material.

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Effect of pH and inhibitors on beta-amyloid fibril assembly

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100166221 ◽

1996 ◽

Vol 54 ◽

pp. 752-753

Author(s):

Beverly E. Maleeff ◽

Timothy K. Hart ◽

Stephen J. Wood ◽

Ronald Wetzel

Keyword(s):

Amyloid Fibril ◽

Peptide Fragment ◽

Hydrophobic Peptides ◽

Amyloid Fibril Formation ◽

Effects Of Ph ◽

Severity Of The Disease ◽

Kinetics Of ◽

The Brain

Alzheimer's disease is characterized post-mortem in part by abnormal extracellular neuritic plaques found in brain tissue. There appears to be a correlation between the severity of Alzheimer's dementia in vivo and the number of plaques found in particular areas of the brain. These plaques are known to be the deposition sites of fibrils of the protein β-amyloid. It is thought that if the assembly of these plaques could be inhibited, the severity of the disease would be decreased. The peptide fragment Aβ, a precursor of the p-amyloid protein, has a 40 amino acid sequence, and has been shown to be toxic to neuronal cells in culture after an aging process of several days. This toxicity corresponds to the kinetics of in vitro amyloid fibril formation. In this study, we report the biochemical and ultrastructural effects of pH and the inhibitory agent hexadecyl-N-methylpiperidinium (HMP) bromide, one of a class of ionic micellar detergents known to be capable of solubilizing hydrophobic peptides, on the in vitro assembly of the peptide fragment Aβ.

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Effects of pH on proton transport by vacuolar pumps from maize roots

Physiologia Plantarum ◽

10.1034/j.1399-3054.1992.860109.x ◽

1992 ◽

Vol 86 (1) ◽

pp. 63-70 ◽

Cited By ~ 1

Author(s):

David Brauer ◽

DeNea Conner ◽

Shu-I Tu

Keyword(s):

Proton Transport ◽

Maize Roots ◽

Effects Of Ph

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DIP quality influenced by process water quality

TAPPI Journal ◽

10.32964/tj13.9.51 ◽

2014 ◽

Vol 13 (9) ◽

pp. 51-60

Author(s):

DENNIS VOSS ◽

HANS-JOACHIM PUTZ ◽

SAMUEL SCHABEL

Keyword(s):

Water Quality ◽

Surface Tension ◽

Ph Value ◽

Water Hardness ◽

Process Water ◽

Test Results ◽

Negative Effects ◽

Water Parameters ◽

Effects Of Ph ◽

Contamination Levels

The need for deinking mills to reduce their fresh water consumption has resulted in higher loads of various contaminants in the process water. Lower recovered paper quality also leads to higher contamination levels in the mills. This higher load has an influence on achievable target brightness. The objective of the work was to determine and explain the main reasons for relatively poor deinked pulp quality or poor deinking potential based on the influence of recovered paper composition and process water quality. The process water parameters significantly affect the deinking potential of recovered paper. The test results showed the negative effects of increased water hardness. For standard recovered paper mixtures, flotation selectivity is higher with increasing flotation pH-value. Good results were realized for standard recovered paper with low hardness, low surface tension, and high pH-value. The results for recovered paper containing flexo newsprint could be slightly improved with low hardness, low surface tension, and low pH-value. The results of the test program using design of experiments showed interacting effects of pH-value and surface tension on luminosity and flotation selectivity.

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In vivo Production of Soluble Inorganic Pyrophosphatases in Two Strains of Vibrio cholerae

Bangladesh Journal of Microbiology ◽

10.3329/bjm.v24i1.1235 ◽

1970 ◽

Vol 24 (1) ◽

pp. 38-41

Author(s):

Taslima Taher Lina ◽

Mohammad Ilias

Keyword(s):

Vibrio Cholerae ◽

Specific Activity ◽

Experimental Conditions ◽

Environmental Strain ◽

Cell Extracts ◽

Atcc Strain ◽

The Family ◽

Effects Of Ph ◽

Vibrio Cholerae O1

The in vivo production of soluble inorganic pyrophosphatases (PPases) was investigated in two strains, namely, Vibrio cholerae EM 004 (environmental strain) and Vibrio cholerae O1 757 (ATCC strain). V. cholerae is known to contain both family I and family II PPase coding sequences. The production of family I and family II PPases were determined by measuring the enzyme activity in cell extracts. The effects of pH, temperature, salinity of the growth medium on the production of soluble PPases were studied. In case of family I PPase, V. cholerae EM 004 gave the highest specific activity at pH 9.0, with 2% NaCl + 0.011% NaF and at 37°C. The strain V. cholerae O1 757 gave the highest specific activity at pH 9.0, with media containing 0% NaCl and at 37°C. On the other hand, under all the conditions family II PPase did not give any significant specific activity, suggesting that the family II PPase was not produced in vivo in either strains of V. cholerae under different experimental conditions. Keywords: Vibrio cholerae, Pyrophosphatases (PPases), Specific activityDOI: http://dx.doi.org/10.3329/bjm.v24i1.1235 Bangladesh J Microbiol, Volume 24, Number 1, June 2007, pp 38-41

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