The Influence of Pre-treatment on the Properties of Photographic Gelatin

Abstract

The influence of the liming period in the manufacturing process on the chemical and photographic properties of gelatin was investigated. Three limed osseins soaked for various periods were prepared and gelatins zvere extracted from them. The impurity contents of the gelatins and the physical restraining properties decreased with prolonging liming periods. The impurity contents and physical retardance were also relative to the extraction order. The deionization treatment of gelatin decreased the impurity contents and the differences of restraining effect with extraction order. Furthermore, the fractionation of sample gelatins by use of gel permeation chromatography was applied to study the relationship to the molecular weight of impurity contents and amino acid composition, as affected by the liming period.     

Kinetic study on reversible addition-fragmentation chain transfer (RAFT) process for block and random copolymerizations of styrene and methyl methacrylate

The degenerative (exchange) chain transfer constant C_ex was determined for the dithioacetate-mediated living radical block and random copolymerizations of styrene (St) and methyl methacrylate (MMA) at 40 °C. The addition of the polystyrene (PSt) radical to a polymer-dithioacetate adduct (P-X) to form the intermediate radical (PSt-(X)-P) was (about twice) faster than that of the poly(methyl methacrylate) (PMMA) radical to form the intermediate radical PMMA-(X)-P. The fragmentation (release) of the PMMA radical from the PSt-(X)-PMMA intermediate formed at the initiating stage of block copolymerization was much (about 100 times) faster than the release of the PSt radical, explaining why the block copolymerization of MMA from a PSt-dithiocarbonate adduct is not so satisfactory as that of St from a PMMA-dithiocarbonate adduct. In the random copolymerization, there was implicit penultimate unit effect on the exchange chain transfer process, which appeared in the addition process but not in the fragmentation process.     

Cell Wall-Denaturing Molecules for Plant Gene Modification

Zwitterionic molecules, such as zwitterionic liquids (ZILs) and polypeptides (ZIPs), are attracting attention for application in new methods that can be used to loosen tight cell wall networks in a biocompatible manner. These novel methods can enhance the cell wall permeability of nanocarriers and increase their transfection efficiency into targeted subcellular organelles in plants. Herein, we provide an overview of the recent progress and future perspectives of such molecules that function as boosters for cell wall-penetrating nanocarriers.     

Dental Pulp-Derived Mesenchymal Stem Cells for Modeling Genetic Disorders

A subpopulation of mesenchymal stem cells, developmentally derived from multipotent neural crest cells that form multiple facial tissues, resides within the dental pulp of human teeth. These stem cells show high proliferative capacity in vitro and are multipotent, including adipogenic, myogenic, osteogenic, chondrogenic, and neurogenic potential. Teeth containing viable cells are harvested via minimally invasive procedures, based on various clinical diagnoses, but then usually discarded as medical waste, indicating the relatively low ethical considerations to reuse these cells for medical applications. Previous studies have demonstrated that stem cells derived from healthy subjects are an excellent source for cell-based medicine, tissue regeneration, and bioengineering. Furthermore, stem cells donated by patients affected by genetic disorders can serve as in vitro models of disease-specific genetic variants, indicating additional applications of these stem cells with high plasticity. This review discusses the benefits, limitations, and perspectives of patient-derived dental pulp stem cells as alternatives that may complement other excellent, yet incomplete stem cell models, such as induced pluripotent stem cells, together with our recent data.     

Vaporized Hydrogen Peroxide and Ozone Gas Synergistically Reduce Prion Infectivity on Stainless Steel Wire

Prions are infectious agents causing prion diseases, which include Creutzfeldt–Jakob disease (CJD) in humans. Several cases have been reported to be transmitted through medical instruments that were used for preclinical CJD patients, raising public health concerns on iatrogenic transmissions of the disease. Since preclinical CJD patients are currently difficult to identify, medical instruments need to be adequately sterilized so as not to transmit the disease. In this study, we investigated the sterilizing activity of two oxidizing agents, ozone gas and vaporized hydrogen peroxide, against prions fixed on stainless steel wires using a mouse bioassay. Mice intracerebrally implanted with prion-contaminated stainless steel wires treated with ozone gas or vaporized hydrogen peroxide developed prion disease later than those implanted with control prion-contaminated stainless steel wires, indicating that ozone gas and vaporized hydrogen peroxide could reduce prion infectivity on wires. Incubation times were further elongated in mice implanted with prion-contaminated stainless steel wires treated with ozone gas-mixed vaporized hydrogen peroxide, indicating that ozone gas mixed with vaporized hydrogen peroxide reduces prions on these wires more potently than ozone gas or vaporized hydrogen peroxide. These results suggest that ozone gas mixed with vaporized hydrogen peroxide might be more useful for prion sterilization than ozone gas or vaporized hydrogen peroxide alone.     

Multi-level selective potentiality maximization for interpreting multi-layered neural networks

Applied Intelligence - The present paper aims to extract the inference mechanism of neural networks, supposed to be hidden in complicated surface phenomena, by maximizing information in terms of...     

Peptide-Mediated Gene Transfer into Marine Purple Photosynthetic Bacteria

Use of photosynthetic organisms is one of the sustainable ways to produce high-value products. Marine purple photosynthetic bacteria are one of the research focuses as microbial production hosts. Genetic transformation is indispensable as a biotechnology technique. However, only conjugation has been determined to be an applicable method for the transformation of marine purple photosynthetic bacteria so far. In this study, for the first time, a dual peptide-based transformation method combining cell penetrating peptide (CPP), cationic peptide and Tat-derived peptide (dTat-Sar-EED) (containing D-amino acids of Tat and endosomal escape domain (EED) connected by sarcosine linkers) successfully delivered plasmid DNA into Rhodovulum sulfidophilum, a marine purple photosynthetic bacterium. The plasmid delivery efficiency was greatly improved by dTat-Sar-EED. The concentrations of dTat-Sar-EED, cell growth stage and recovery duration affected the efficiency of plasmid DNA delivery. The delivery was inhibited at 4 °C and by A22, which is an inhibitor of the actin homolog MreB. This suggests that the plasmid DNA delivery occurred via MreB-mediated energy dependent process. Additionally, this peptide-mediated delivery method was also applicable for E. coli cells. Thus, a wide range of bacteria could be genetically transformed by using this novel peptide-based transformation method.