Evaluation of an Immunoisolation Membrane Formed by Incorporating a Polyvinyl Alcohol Hydrogel within a Microporous Filter Support

1997 ◽  
Vol 6 (6) ◽  
pp. 585-595 ◽  
Author(s):  
Andrew R. Baker ◽  
Ronald L. Fournier ◽  
Jeffrey G. Sarver ◽  
Jennifer L. Long ◽  
Peter J. Goldblatt ◽  
...  
Keyword(s):  
Polyvinyl Alcohol ◽  
Water Content ◽  
Structural Integrity ◽  
High Water ◽  
Membrane Properties ◽  
High Water Content ◽  
Hybrid Hydrogel ◽  
Wide Range ◽  
Pva Hydrogel

An immunoisolation membrane formed by incorporating a high water content polyvinyl alcohol (PVA) hydrogel into a microporous polyether sulfone (PES) filter has been investigated in this study. The PVA hydrogel is formed in situ within the filter pores via glutaraldehyde (GA) crosslinking under acidic conditions. The tortuous nature of the microporous filter pores securely anchors the embedded hydrogel to provide excellent structural integrity. The high void fraction of the PES filter support (>80%) and high water content of the PVA hydrogel (>85% water by weight) allow excellent solute transport rates, while an appropriate level of glutaraldehyde crosslinking supplies the required molecular size selectivity. In vitro permeability measurements made with solutes covering a wide range of molecular sizes demonstrate high transport rates for small nutrient molecules with rapidly diminishing permeabilities above a molecular weight of approximately 1,000 Dalton. Implantation experiments show that the membrane properties are not deleteriously affected by prolonged in vivo exposure or common sterilization techniques. Thus, this hybrid hydrogel/filter membrane system offers a promising approach to the immunoisolation of implanted cells.

Ultra-absorbent hybrid hydrogel based on alginate and SiO2 microspheres: A high-water-content system for removal of methylene blue

2019 ◽  
Vol 276 ◽  
pp. 204-213 ◽  
Author(s):  
Caroline O. Panão ◽  
Eduardo L.S. Campos ◽  
Hugo H.C. Lima ◽  
Andrelson W. Rinaldi ◽  
Michele K. Lima-Tenório ◽  
...  
Keyword(s):  
Methylene Blue ◽  
Water Content ◽  
High Water ◽  
High Water Content ◽  
Hybrid Hydrogel ◽  
Content System ◽  
Sio2 Microspheres

Development of Polyvinyl Alcohol-Hydrogel (PVA-H) Shields with a High Water Content for Tendon Injury Repair

2001 ◽  
Vol 26 (5) ◽  
pp. 436-440 ◽  
Author(s):  
M. KOBAYASHI ◽  
J. TOGUCHIDA ◽  
M. OKA
Keyword(s):  
Polyvinyl Alcohol ◽  
Water Content ◽  
Flexor Tendon ◽  
Adhesion Formation ◽  
Tendon Repair ◽  
High Water ◽  
Tendon Injury ◽  
Surrounding Tissue ◽  
High Water Content ◽  
Injury Repair

The main problem in tendon repair is adhesion formation between the tendon and surrounding tissue. To prevent this, we have developed adhesion preventive shields using polyvinyl alcohol hydrogel (PVA-H) with 90% water content. This implant experiment used the deep flexor tendon of the 3rd toe of the domestic fowl. Injured tendons shielded with PVA-H healed within about 3 weeks without adhesion to the surrounding tissues. Neither breakage of the PVA-H shield itself nor infection or degeneration in the surrounding tissue was observed. These results show that tendon is capable of intrinsic repair, and was able to regenerate using synovial nutrition through the PVA-H. The high water content of PVA-H may be clinically useful and applicable to adhesion preventive shields for tendon repair.

Preparation and characterization of modified chitosan for in vitro controlled release of vitamin B12

2013 ◽  
Vol 33 (8) ◽  
pp. 757-765 ◽  
Author(s):  
Ahmed Awadallah-F ◽  
Tahia B. Mostafa
Keyword(s):  
Water Content ◽  
Monomer Concentration ◽  
High Water ◽  
High Water Content ◽  
Vitamin B ◽  
Acryloyl Chloride ◽  
Modified Chitosan ◽  
Increase With Increase

Abstract Graft copolymerization of acrylonitrile and acryloyl chloride on to chitosan was prepared by γ-rays. Optimization of the grafting (%) was studied. The grafting (%) was observed to increase with increase in the irradiation dose and monomer concentration. The grafting percentages were about 52% and 36% from polyacrylonitrile and poly(acryloyl chloride), respectively. Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) were used to characterize the specimens. The modified chitosan was loaded with vitamin B12, demonstrated nearly 5.0±2.3% and 50.1±4.5% release in the media of pH 1.2 and 6.8, respectively, for amidoximated chitosan-grafted polyacrylonitrile and 3.6±1.1% and 36±2.4% in pH 1.2 and 6.8, respectively, for chitosan-grafted poly(acryloyl chloride), as determined by a traditional dissolution model. The modified chitosan specimens that uploaded with vitamin B12 displayed a more decremental release in the acidic medium than the neutral one. However, in order to incorporate in vivo gastrointestinal conditions, such as acidic pH and high water content in the stomach, low water content, and the presence of semi-solid mass in the large intestine, a new model, called flow through diffusion cell, was also used to study the drug release. The results of the two approaches produced different release profiles at the same pH values.

scholarly journals Optimalization of multiresidue method for the determination of pesticide residues in fruits

2021 ◽  
Vol 61 (3) ◽  
pp. 221-238
Keyword(s):  
Water Content ◽  
Pesticide Residues ◽  
High Water ◽  
High Water Content ◽  
Detector Response ◽  
Wide Range ◽  
Comprehensive Determination ◽  
Selective Detectors ◽  
Active Substances

The main aim of this study was to optimize the QuEChERS methodology for the comprehensive determination of pesticide residues using a simple and inexpensive gas chromatography equipped with selective detectors working simultaneously (GC-ECD/NPD). The method was validated in accordance with the SANTE/11945/2015 guidelines. Representative fruit matrices were chosen from the commodities group with high water content (apples), and with high acidity and high water content (strawberry) for a 160 compounds in the range of 0.005−0.02 mg/kg. The accuracy of the method was as required (recovery: 70–120%, precision: below 20%) for 135 active substances in apples samples and 137 in strawberries samples. The main advantages of the methodology include: good detector response linearity (R2 above 0.995), low limits of detection (0.005 mg/kg for more than 20 compounds, 0.01 mg/kg for about 120 compounds), possibility of simultaneous determination of a wide range of compounds (including some “difficult” ones) without use of a single residue methods. The simultaneous use of two selective detectors allows to obtain more data during a single dose of the sample and confirmation of the result for most compounds, which allows to prevent false positives ones.

scholarly journals Viability and germination of Scots pine seeds after freezing of harvested cones in vitro

2016 ◽  
Vol 46 (8) ◽  
pp. 1035-1041
Author(s):  
Markku Nygren ◽  
Katri Himanen ◽  
Hanna Ruhanen
Keyword(s):  
Water Content ◽  
Scots Pine ◽  
Seed Viability ◽  
High Water ◽  
Logistic Function ◽  
High Water Content ◽  
Maturation Stage ◽  
Freezing Treatment ◽  
Water Contents

Scots pine (Pinus silvestris L.) cone and seed water contents were analyzed in two consecutive seasons during maturation stage in the autumn and in January and March before seed dispersal. Cones with different water contents were subjected to 2 h of freezing at −30 °C, and seed viability and laboratory germination of seeds from individual cones after treatment were analyzed. Seed water content could be well predicted with the measurement of the cone water content, and the general relationship between these two could be described with a generalized logistic function. On average, the water content of cones was 5%–10% units higher than the seeds inside them. The higher the cone water content at the onset of freezing treatment, the higher the proportion of seeds with apparent damage (based on visual inspection of seeds using X-ray images) in that particular cone. High water content in cones also resulted in decreased germination after freezing treatment. The critical cone water content for 50% germination after freezing at −30 °C was approximately 31.3% (fresh mass basis). This corresponds to 21.6% water content in seeds.

High-water-content graphene oxide/polyvinyl alcohol hydrogel with excellent mechanical properties

2014 ◽  
Vol 2 (27) ◽  
pp. 10508-10515 ◽  
Author(s):  
Yifu Huang ◽  
Mingqiu Zhang ◽  
Wenhong Ruan
Keyword(s):  
Mechanical Properties ◽  
Graphene Oxide ◽  
Polyvinyl Alcohol ◽  
Water Content ◽  
High Water ◽  
High Water Content ◽  
Cross Linking ◽  
Freeze Thaw

Boron-cross-linked graphene oxide/polyvinyl alcohol (B-GO/PVA) hydrogels with high-water-content and excellent mechanical properties are prepared by freeze/thaw and boron cross-linking methods.

Fluorescence sensors for detection of water based on tetraphenylethene–anthracene possessing both solvatofluorochromic properties and aggregation-induced emission (AIE) characteristics

2021 ◽  
Vol 45 (9) ◽  
pp. 4164-4173
Author(s):  
Yuta Mise ◽  
Keiichi Imato ◽  
Takashi Ogi ◽  
Nao Tsunoji ◽  
Yousuke Ooyama
Keyword(s):  
Water Content ◽  
High Water ◽  
Fluorescence Sensor ◽  
High Water Content ◽  
Fluorescence Sensors ◽  
Aggregation Induced Emission ◽  
Emission Enhancement ◽  
Wide Range ◽  
Water Based

TPE-(An-CHO)4 has been developed as an SFC (solvatofluorochromism)/AIEE (aggregation-induced emission enhancement)-based fluorescence sensor for detection of water over a wide range from low to high water content regions in solvents.

scholarly journals Oxidation Lipid on Fish Cake Catfish (Pangasius sp.) Dissolved in The Extract of Bay Leaf (Eugenia polyantha)

2020 ◽  
Vol 8 (3) ◽  
pp. 91
Author(s):  
Mahiastuti Tribuana Tungga Dewi ◽  
Boedi Setya Rahardja ◽  
Agustono Agustono
Keyword(s):  
Water Content ◽  
Natural Antioxidants ◽  
High Water ◽  
Experimental Methods ◽  
Quality Score ◽  
High Water Content ◽  
Antioxidant Compounds ◽  
White Meat ◽  
Wide Range ◽  
Significant Difference

Catfish (Pangasius sp.) As a source of animal protein. Fish catfish have a thick white meat so that it can be processed into a wide range of diversified products. The process of fried fish cake can result in fat or autooxidation process. Autooxidation can be inhibited by the presence of antioxidant compounds. One source of natural antioxidants are bay leaf Eugenia polyantha.This research was carried out by experimental methods and the use of experimental design of randomized Complete Design (RAL). RAL is used when the material and condition of the experiment are homogeneous. This research consists of four concentrations of extract treatment bay leaf, namely 0%, 10%, 20%, 30%. Fish cake has been fried done soaking for 30 minutes. Water content showed no significant difference (p> 0.05) at 24 hours to 28, this indicated that the addition of bay leaf extract did not affect the moisture content during storage. The high water content at 0 hour is caused by the process of soaking the fish cake  in the extract solution. The highest value is shown by the concentration of 30% at the hour to 0 that is 52.78%, this indicates that the fish cake by soaking can meet the quality score SNI 7757:2013 which is a maximum of 60%. The fat content in the fish cake continues to decrease, indicating the occurrence of oxidation during storage. Levels of TBA in fish cake continue to increase that can be slowed by the extract of bay leaves with a concentration of 30%.

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