Amount Of Gelatin Research Articles

Influence of carbon black distribution on performance of oxide cathodes for Li ion batteries

The influence of carbon black content and carbon black distribution on performance of oxide-based cathodes, such as LiCoO 2 and LiMn 2O 4, is investigated. The electronic conductivity of oxide material/carbon black composites is compared with electrochemical characteristics of the same composites. Uniformity of carbon black distribution in cathode composites is achieved using novel coating technology in cathode preparation. In this technology, the active particles are first pretreated in a gelatin solution. The adsorbed gelatin then controls the deposition of carbon black so that carbon black particles are uniformly distributed in the final composite. The influence of various parameters, such as pH of gelatin, amount of gelatin and concentration of carbon black on the uniformity of carbon black distribution is investigated. It is shown that the conventional technology of cathode preparation yields quite non-uniform distribution of carbon black in cathode material. At the end, we demonstrate that uniformity of carbon black distribution has a crucial impact on reversible capacity, especially at high current densities.

Current Literature: 1

Objective Anaphylaxis after immunization, although rare, is serious and potentially life‐threatening. Understanding risk factors for this reaction is therefore important. Gelatin is added to many vaccines as a heat stabilizer. Japanese researchers have demonstrated a strong association between immediate hypersensitivity reactions to measles, mumps, rubella, varicella, and Japanese encephalitis immunizations and subsequent detection of antigelatin immunoglobulin E (IgE) antibodies. They suggested that previous receipt by these patients of diphtheria–tetanus–acellular pertussis vaccines with trace amounts of gelatin was responsible for the sensitization. We aimed to assess whether a similar association exists for vaccinees in the United States who reported anaphylaxis after receipt of measles–mumps–rubella (MMR) or measles vaccines and to review recent trends in reporting of hypersensitivity reactions.Methods We conducted a retrospective case–control study. Cases of anaphylaxis that met a predefined case definition were identified from the US Vaccine Adverse Event Reporting System (VAERS). Mayo Clinic patients who received MMR vaccine uneventfully served as controls. The study subjects were interviewed to obtain the history of allergies. Sera from study subjects and their matched controls were tested for IgE antibodies to gelatin, whole egg and vaccine viral antigens using solid‐phase radioimmunoassay. Data from the Biologics Surveillance System on annual numbers of doses of MMR and varicella vaccines distributed in the United States were used to evaluate possible changes in reporting of selected allergic adverse events.Results Fifty‐seven study subjects were recruited into the study and interviewed. Of these, 22 provided serum samples for IgE testing. Twenty‐seven subjects served as a comparison group and provided a sample for IgE testing; 21 of these completed an allergy history questionnaire. Self‐reported history of food allergies was present more frequently in the interviewed study subjects than in the controls, whereas the proportions of people with other characteristics were similar in both groups. None of the interviewed people had a history of food allergy to gelatin. The level of antigelatin IgE antibodies was significantly higher among study subjects than among controls, whereas the levels of IgE antibodies against egg and all three viral antigens did not differ significantly. Of 22 study subjects, six (27%) tested positive for antigelatin IgE, whereas none of the 27 controls did. The rate of anaphylactic reactions reported to VAERS after measles virus‐containing immunization in the United States between 1991 and 1997 is 1.8 per 1 million doses distributed. No substantial increase in the number of reported allergic events after frequently used gelatin containing MMR and varicella vaccines could be observed during the first 4 years (1997–2000) since the introduction of diphtheria–tetanus–acellular pertussis vaccines for use in infancy.Conclusion Anaphylactic reactions to MMR in the United States are rare. The reporting rate has the same order of magnitude as estimates from other countries. Almost one‐quarter of patients with reported anaphylaxis after MMR seem to have hypersensitivity to gelatin in the vaccine. They may be at higher risk of developing anaphylaxis to subsequent doses of other gelatin‐containing vaccines. These people should seek an allergy evaluation before such immunization.

A novel amperometric biosensor based on spinach ( Spinacia oleracea) tissue homogenate for urinary oxalate determination

In this study, a novel spinach ( Spinacia oleracea) tissue homogenate-based biosensor for determination of oxalate in urine was developed. The biosensor was constructed by immobilizing tissue homogenate of spinach ( S. oleracea) onto a high-sensitive teflon membrane of a dissolved oxygen (DO) probe. For the stability of the biosensor, general immobilization techniques were used to secure the spinach tissue homogenate in gelatin-glutaraldehyde cross-linking matrix. In the optimization and characterization studies, the amount of spinach tissue homogenate and gelatin, optimum pH, optimum temperature and thermal stability, interference effects, linear range and repeatability were investigated. A typical calibration curve for the sensor revealed a linear range of 1×10 −5–10×10 −5 M oxalate. In repeatability studies, variation coefficient (CV) was calculated as 1.8%. Of the various substrates tested, only oxalate was found to be specific, with a relative activity of 100%. The method was applied to the determination of oxalate in urine. The results showed that the method was applicable to oxalate determination in urine specifically and selectively.

Immobilization of glutathione-s-transferase within cross-linked gelatin cylindrical molds.

Rabbit liver cytosolic glutathione-s-transferase (GSTs; EC: 2.5.1.18) was immobilized in cross-linked gelatin cylindrical molds which the formaldehyde was used as cross linker. Glutathione-s-transferases are the enzymes that catalyze the conjugation of wide variety of electrophilic substrates with glutathione. This process generally leads to the detoxification of the xenobiotics. Characterization of immobilized GST was made by using 1-chloro-2,4-dinitrobenzene(CDNB) as substrate. Immobilization efficiency of the enzyme was calculated in terms of activity yield. Optimal enzyme, gelatin and formaldehyde amounts, optimum pH and temperature, Km[CDNB], Km[GSH] and thermal stability was searched and compared with the free enzyme. Furthermore, for studying the detoxification by conjugation in vitro, immobilized GST was tested using stirred batch reactor system and found suitable with a high yield of 2,4-dinitrophenyl-GSH conjugate formation.

銅電解精製における高分子添加剤の影響

Effects of polymer additives such as gelatin and polyethylene glycol (PEG) on Cu electrodeposition behavior have been investigated by measuring the polarization curves for Cu deposition and the amount of additive adsorbed on Cu powder. Gelatin and PEG act as a polarizer for Cu deposition to shift the cathode potential in a less noble direction. The degree of polarization increased with an increase in the concentration and the molecular weight of additives, while the polarization effect of PEG was decreased when the molecular weight exceeded 103. Since the amount of gelatin adsorbed on Cu powder increased with increasing the molecular weight, the polarization effect of gelatin appears to depend on its adsorptive activity on the cathode. The morphology of deposited Cu showed the compacted surface composed of fine grains with an increase in the polarization of cathode potential by the additives.

Small-Angle Neutron Scattering of Gelatin/Sodium Dodecyl Sulfate Complexes at the Polystyrene/Water Interface

Using isotopic substitution, the small-angle neutron scattering from a gelatin layer preadsorbed upon polystyrene latex has been measured as a function of the added concentration of sodium dodecyl sulfate (SDS). The data have been fitted using a model which includes an exponential volume fraction profile and a term to account for the scattering from spatial concentration fluctuations. Measurements indicate that the gelatin layer thickness increases to a maximum as a function of SDS concentration, while the volume fraction of gelatin adsorbed at the interface simultaneously decreases. Consequently, the adsorbed amount of gelatin peaks at SDS concentrations equivalent to approximately one SDS micelle/gelatin chain. Further addition of SDS sees the adsorbed amount decay below that of the system in the absence of SDS. At the highest SDS concentrations, the gelatin also develops a scattering form similar to that of SDS micelles.

Surface modification of polycaprolactone with poly(methacrylic acid) and gelatin covalent immobilization for promoting its cytocompatibility

Polycaprolactone (PCL) membrane was modified by grafting copolymerization of methacrylic acid (MAA) initiated under UV light. The covalent immobilization of gelatin on PCL-g-PMAA surface was consequently performed by using condensing agent, 1-ethyl-3-(3-dimethylamino propyl) carbodiimide hydrochloride. The occurrence of grafting copolymerization of PMAA and further immobilization of gelatin was confirmed by ATR-FTIR and X-ray photoelectron spectroscopy characterizations. The existence of carboxyl groups grafted on PCL surface was verified quantitatively by absorbance spectroscopy where rhodamine 6G was employed to react with carboxyl groups to generate an absorbance at 512 nm. The endothelial cell culture proved that the PCL membrane slightly modified with suitable amount of PMAA or gelatin had better cytocompatibility than control PCL or PCL membrane heavily modified with PMAA or gelatin.

USING GELATIN‐BASED ANTIMICROBIAL EDIBLE COATING TO PROLONG SHELF‐LIFE OF TILAPIA FILLETS

Abstract Skinless tilapia (Dreochromis niloticus x D. aureus) fillets were covered with a gelatin coating containing benzoic acid as an antimicrobial agent. Benzoic acid content of fish fillets was used to estimate the amount of gelatin coated on fillet surface, and it was found that the gelatin contents were between 16.3 mg and 17.3 mg per g of fillets. Aerobic and anaerobic microbial loads, volatile basic nitrogen (VBN) contents, and sensory evaluation were used as indicators to survey the feasibility of an antimicrobial gelatin coating to prolong the shelf‐life of tilapia fillets under refrigeration. After 7 days of storage under refrigeration, tilapia fillets coated with gelatin containing benzoic acid had acceptable VBN contents, increased moderately in microbial loads, and showed no significant sensory difference (P < 0.05) from fresh fillets. The results indicate that an antimicrobial gelatin coating is suitable for preservation of tilapia fillets.

Interpenetrating polymer networks based on poly(acrylic acid) and gelatin. I: Swelling and thermal behavior

AbstractThis article describes the synthesis of full and semi‐interpenetrating polymer networks (IPNs) based on poly(acrylic acid) and gelatin as polymers 1 and 2, which were crosslinked sequentially using N,N′‐methylene bisacrylamide (BAm) and glutaraldehyde, respectively. Various samples were prepared by taking varying amounts of acrylic acid and gelatin in the initial feed. Sequential IPNs were prepared by first polymerizing and crosslinking acrylic acid in the presence of gelatin using redox initiators (ammonium persulphate and sodium metabisulphite) and BAm as a crosslinking agent. Gelatin present in the firm gels was then crosslinked using 4% glutaraldehyde. Characterization of these gels was done by measuring their swelling behavior as a function of pH, temperature, and time. Percent swelling increased with increasing amounts of acrylic acid. The swelling ratio was also determined in the pH range of 1 to 12. Acid/alkali or buffers were used for maintaining pH. A significant increase in the percent swelling was observed when pH of distilled water was above 10. On the other hand, in the case of buffer, the swelling ratio increased with increasing the pH, and a maxima was observed at pH 8.4. A further increase in pH resulted in a decrease in the swelling ratio. Thermal and morphological characterization was done using thermogravimetric analyzer and scanning electron microscopy, respectively. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 217–227, 2001

Protein precipitating capacity of condensed tannins of beach pea, canola hulls, evening primrose and faba bean

Abstract Condensed tannins (CT) from beach pea, Cyclone canola hulls, evening primrose and faba bean were extracted into 70% (v/v) aqueous acetone. The lyophilized extracts were then purified on a Sephadex LH-20 column using first 95% ethanol as a mobile phase for elution of non-tannin phenolics and then 50% aqueous acetone to elute CT. Condensed tannins isolated from beach pea possessed shorter polymer chains than those isolated from canola hulls, evening primrose or faba bean. Bovine serum albumin (BSA) was effectively precipitated by beach pea CT at pH values between 3.5 and 5.0. CT of canola hulls, evening primrose and faba bean precipitated BSA at pH 4.0–5.0. A statistically significant ( P =0.0001) linear relationship existed between the amount of tannin-protein complex formed and the amount of CT added to the reaction mixture. The slopes of these lines indicated that evening primrose CT were the most effective protein precipitants, followed by canola hulls, faba bean and beach pea CT. Based on the amount of gelatin and BSA required to inhibit 50% of dye-labelled BSA-CT complex precipitation, gelatin was 10 times more effective as a precipitation inhibitor than unlabelled BSA.

In vitro tubulogenesis of endothelial cells by relaxation of the coupling extracellular matrix-cytoskeleton.

This investigation aimed at determining the importance of the rigidity of the adhesive support and the participation of the cytoskeleton in tubulogenesis of endothelial cells in vitro. The morphotype, biosynthetic phenotype and cytoskeleton organization of human umbilical vein endothelial cells (HUVEC) were analyzed on supports of variable mechanical resistance. Western blot analysis revealed a strong reduction of the expression of actin and focal-adhesion plaque (FAP) proteins in HUVEC organized in tube-like structures (TLS) on soft matrigel or on matrigel co-polymerized with heat-denatured collagen as compared to HUVEC remaining in a monolayer pattern on rigid matrigel-coat or on matrigel co-polymerized with type I collagen. Human skin fibroblasts morphotype was not altered in these culture conditions and the pattern of FAP proteins and actin was not modulated. By using polyacrylamide gels polymerized with various concentrations of bis-acrylamide to modulate the mechanical resistance of the support and cross-linked to a constant amount of gelatin to provide an equal density of attachment sites, it was shown that the less rigid the support, the more endothelial cells switched to a tube-like pattern. Collagen type I-induced tubulogenesis was accompanied by a profound and reversible remodeling of the actin-FAP complex suggesting a weakening of the bridging between extracellular matrix (ECM) and the cytoskeleton. Human skin fibroblasts and smooth muscle cells, used as control cells, adhered strongly to the collagen, did not form TLS and their network of actin stress fibers was not remodeled. The inhibition of collagen type I-induced tubulogenesis by agents altering the actin cytoskeleton-FAP complex including calpain type I inhibitor, orthovanadate, KT5720 and jasplakinolide, further supports the determinant role of mechanical coupling between the cells and the matrix in tubulogenesis. A reduced tension between the endothelial cells and the extracellular matrix, originating in the support or within the cells is sufficient to trigger an intracellular signaling cascade leading to tubulogenesis, an event mimicking one of the last steps of angiogenesis.

IgE sensitization to gelatin: the probable role of gelatin-containing diphtheria–tetanus–acellular pertussis (DTaP) vaccines

We recently found that most events of anaphylaxis to live attenuated viral vaccines containing gelatin as a stabilizer might be caused by the gelatin. However, the mechanism that the children were sensitized to gelatin was unclear. In Japan, both diphtheria–tetanus–acellular pertussis (DTaP) vaccines with and without gelatin are available. We explored the possibility that gelatin-containing DTaP vaccines before live viral vaccines sensitize children to gelatin. We received the serum samples of 87 children who had systemic immediate-type reactions including anaphylaxis to the vaccines from both physicians and vaccine manufacturers throughout Japan. We then surveyed the DTaP vaccination histories of the children who demonstrated anti-gelatin IgE. Of the above 87 children, 79 (91%) had anti-gelatin IgE. We successfully collected DTaP vaccination histories including the manufacturers’ names and numbers of doses on 55 children. Only one child had not received any DTaP vaccine, the other 54 had received gelatin-containing DTaP vaccines and none received gelatin-free DTaP vaccines. We concluded that there was a strong causal relationship between gelatin-containing DTaP vaccination, anti-gelatin IgE production, and risk of anaphylaxis following subsequent immunization with live viral vaccines which contain a larger amount of gelatin.

Biodegradation of chemically modified gelatin films in lake and river waters

Gelatin was chemically modified by crosslinking samples with one of a number of bifunctional reagents as was done earlier in a processing technique used to improve mechanical properties through chain orientation. The effects of this crosslinking on the biodegradability of the resulting films were evaluated in the laboratory by exposing them to lake and river waters for 10 days with or without inoculation with periphyton organisms. Biodegradabilities were assessed by weight losses of the films and by measurements of dehydrogenase activity of biomasses taken from their surfaces. The extent of biodegradation depended on the type of crosslinking agent and the presence or absence of the periphyton. The gelatin films crosslinked with formaldehyde, glyoxal, or glutaraldehyde were the slowest to biodegrade; complete degradation required 8-10 days. In contrast, the most biodegradable was the gelatin crosslinked with hexamethylene diisocyanate, which required only 3-4 days. The uncrosslinked gelatin and the gelatin crosslinked with butadiene diepoxide and diepoxyoctane were intermediate, degrading in 5-7 days. The dehydrogenase activity paralleled the weight losses but rapidly decreased when the amount of gelatin remaining was small.

Swelling behavior and mechanical properties of chemically cross-linked gelatin gels for biomedical use.

Cross-linked gelatin gels are used as biomaterials in living tissues, either as bioadhesives or as devices for sustained drug release. As these applications involve surgical insertion of gels, the effect of cross-linking on mechanical properties is relevant. The effect of cross-linking on the gel water uptake is also relevant for the kinetics of drug release. Equally important is the influence of initial amounts of gelatin in the gelling solutions. We investigated the influence of cross-linking (with glutaraldehyde) and of gelatin content upon the equilibrium water content and tensile properties of resulting gels. A range of gels was prepared with gelatin contents of 10 to 40% wt, and cross-linked with 2.5 to 50% wt glutaraldehyde. The increase in gelatin content and degree of cross-linking reduced the water uptake of gels from about 60-65% wt to about 50% wt. The tensile characteristics were differentially affected. While the increase of cross-linking induced a decrease of toughness and elasticity and an increase of stiffness, it did not affect the ultimate strength of gels. On the contrary, the increase of gelatin content induced a definite increase of the ultimate strength but did not significantly affect the other properties.

Alumina casting based on gelation of gelatine

A new colloidal in-situ forming technique based on the gelling property of gelatine is discussed in this paper. A warm slurry containing more than 50 vol% alumina powder and a small amount of gelatine (∼1 wt% of powder weight) is cast into a nonporous mould, and a rigid green body can be produced upon cooling below the so-called gel point of gelatine (15–20°C). The mixed slurry is a pseudo plasticity fluid with an apparent viscosity lower than 1 Pa·s. After dying, ceramic compacts can be sintered without special debinding operations due to the small amount of binder.

Thrombelastogram reveals hypercoagulability after administration of gelatin solution

We have compared the effects of gelatin, low molecular weight hydroxyethyl starch (HES) or albumin on tests of haemostasis and on the thrombelastogram in 42 ASA I patients undergoing total hip or knee replacement. Patients were allocated randomly to receive one of the three blood substitutes to obtain moderate intraoperative haemodilution. Blood loss and packed red cell infusion was the same in each group. A greater amount of gelatin was given (1.5 times the measured blood loss) because of its shorter half-life. There was a statistically significant but clinically negligible decrease in platelets count, prothrombin time and fibrinogen, and an increase in bleeding time in all groups. Platelets were slightly but significantly lower after HES. Haemodilution was comparable between groups. TEG showed a state of hypercoagulability in the gelatin group with a significant decrease in r, r + k and an increase in alpha angle.

Competitive Adsorption of Gelatin and Sodium Dodecylbenzenesulfonate at Hydrophobic Surfaces

The competitive adsorption of gelatin and sodium dodecylbenzenesulfonate (SDBS) at hydrophobic surfaces was investigated with surface and interfacial tension measurements, ellipsometry, surface plasmon resonance spectroscopy (SPR), and total internal reflectance fluorescence spectroscopy (TIRF). From both ellipsometry and SPR, initial additions of SDBS after gelatin preadsorption were found to result in a total adsorbed amount increase, as well as in a swelling of the adsorbed layer. At higher SDBS concentrations, both the total adsorbed amount and the amount of gelatin adsorbed decrease, which was observed from ellipsometry, SPR, and TIRF. From surface and interfacial tension measurements, it was found that the critical aggregation concentration (cac) for the SDBS−gelatin system decreases with decreasing pH. Analogous to this, ellipsometry, SPR, and TIRF indicate that the SDBS concentration required to cause a significant decrease in the gelatin adsorbed amount decreases with decreasing pH. The desorption therefore seems to be correlated to the SDBS binding to the adsorbed gelatin molecules rather than to purely competitive adsorption.

Lipase-catalysed stereoselective esterifications using gelatin-based hydrogels

A hydrogel stable in an organic solvent has been developed. This pseudo-solid aqueous gel (PAG) consists of only native gelatin and water, and has been used for immobilization of enzymes. A relatively high amount of gelatin is required in order to obtain stable gels. PAGs containing the enzyme Candida antarctica lipase (SP 525) were successfully used in catalysing the esterification of R/ S-(±)-2-octanol and hexanoic acid in hexane. The conversions as well as the enantiomeric excess values of the product, R-(−)-2-octyl hexanoate, were high and comparable to those obtained with microemulsion-based gels. The PAGs containing immobilized lipase gave reproducible results and may be re-used several times. The gels are easy to prepare and use, non-toxic and biocompatible. The PAGs retain their integrity in organic solvents and may be used in preparative-scale synthesis of organic compounds.

An inexpensive solid medium for obtaining colony-forming units of oral spirochetes.

A method for the enumeration of colony-forming units of oral anaerobic spirochetes in new oral spirochete agarose (NOS-A) medium was described recently. However, the high cost of agarose limits the extent to which large assays can be carried out. Accordingly, a search for an inexpensive gelling agent that remains molten at 37 degrees C and gels at 25 degrees C was undertaken. Varying amounts of Noble agar or Bacto agar (0.5 to 1.5%, w/v) were mixed with varying amounts of gelatin (0.5 to 1.0%, w/v) in NOS medium. NOS medium containing 0.5% gelatin-0.5% Noble agar (NOS-GN) or 0.5% gelatin-0.5% Bacto agar (NOS-GB) met the above criteria. NOS-GN and NOS-GB media yielded higher colony-forming units with Treponema denticola than NOS-A medium in that order. However, all three media, NOS-GN, NOS-GB and NOS-A, performed equally well in the recovery of viable counts of T. vincentii. The NOS-GN medium was not liquefied by subgingival bacteria or two gelatinase-producing species of bacteria, Bacillus subtilis and Staphylococcus aureus. Thus NOS-GN medium is the recommended medium both in cost and performance for obtaining colony counts of spirochetes.

Comparison of additives in the removal of phenolic compounds by peroxidase-catalyzed polymerization

Several additives, polyethylene glycol, gelatin and some polyelectrolytes, were studied to compare their behaviour in the removal of phenolic compounds from aqueous solution by horseradish-peroxidase-catalyzed polymerization. The effects of additives on optimum pH range, horseradish-peroxidase saving, reaction stoichiometry and minimum additive requirements were investigated. The fate of additive after reaction was also studied. The experimental results showed that all tested additives significantly reduced the horseradish-peroxidase requirement. Comparison among them revealed that polyethylene glycol was the best choice from all perspectives. It saved more peroxidase and had no negative overdose effect shown by gelatin and polyelectrolytes. At minimum polyethylene glycol dose, there was little polyethylene glycol remaining in solution after completion of reaction. However, a considerable amount of gelatin remained in solution even at the minimum gelatin dose. Also, gelatin produced more precipitate than polyethylene glycol.