Development of Polyol Ester Refrigeration Oils for HFO Refrigerants

Recently, R32 refrigerant, which has low global warming potential (GWP), attracts much attention as an alternative one instead of R410A and has started to be used in practical system of room air conditioner (RAC), but compared with natural refrigerants, its GWP of 675 is still high and it is required to use refrigerants with much lower GWP. In addition, although R134a (GWP=1300) is widely used for mobile air conditioner systems (MAC), it has been decided by MAC directive in Europe that refrigerants whose GWP is over 150 can no longer be available in future. In such a situation, HFO refrigerants like R1234yf, R1234ze and AMOLEA [1] are considered as candidates for next-generation refrigerants because of their much lower GWP. Therefore, at the same time, it is required to develop refrigeration oils which have good compatibility with HFO refrigerants for RAC. One of the characteristics of HFO refrigerants is that their miscibility with refrigeration oils is equal to or greater than that of HFCs. However, the problem is that HFOs have a double bond in their molecular structure, resulting in their lower chemical stability than that of HFCs. We developed polyol ester (POE) refrigeration oil with high chemical stability under HFO atmospheres by improving formulation of additives. In this study, we will report the method and the characteristics of lubricity under HFOs. [1] M. Fukushima, M. Hashimoto, Development of Low-GWP Alternative Refrigerants , JRAIA the International Symposium on New Refrigerants and Environmental Technology 2014, (2014), 292-299

Development of refrigeration oil for use with R32

R32 has been applied as an air-conditioner refrigerant in Japan for a few years. Although its GWP is slightly higher than the limit of F-gas restriction, high COP is a key driving force for R32 system. Regarding refrigeration oil applied to R32, there are two main issues. First issue is miscibility with R32, because incumbent refrigeration oil for R410A is rather immiscible to R32. Second issue is lubricity. When refrigerant is miscible well with refrigeration oil, generally, dissolved refrigerant reduce viscosity of refrigerant-oil mixture. Lower viscosity results in, lower lubricity, and finally, it would cause wear of sliding parts, compressor durability shortage, insufficient sealing, or reduced COP. At the earlier stage, several refrigeration oils miscible with R32 have been proposed. However, we have experienced wearing problems on surface of a main shaft in R32 system with such refrigeration oils, for example. Those problems were not found in R410A systems. We assumed there is some different mechanism on sliding parts in R32 systems comparing with current refrigerant systems. We focused on viscosity of refrigerant – oil mixture, which could be correlated to lubricity. Then, we found that viscosity of R32 – refrigeration oil mixture is extremely lower than that of R410A – refrigeration oil. Together with results of wearing problem in sliding parts, which are not worn by fluid lubrication in general, we assumed that oil film is formed insufficiently on the surface due to the extreme low viscosity of the mixture. Our goal of development of refrigeration oil for R32 was reset to balance miscibility and lubricity, which is trade-off normally. Through various studies, finally, we found a new base oil to meet our goal, which makes us possible to achieve not only high viscosity of the mixture, but also good miscibility with R32. Its excellent characteristics on lubricity and miscibility are also confirmed by several compressor tests

Curated genome annotation of Oryza sativa ssp. japonica and comparative genome analysis with Arabidopsis thaliana

We present here the annotation of the complete genome of rice Oryza sativa L. ssp. japonica cultivar Nipponbare. All functional annotations for proteins and non-protein-coding RNA (npRNA) candidates were manually curated. Functions were identified or inferred in 19,969 (70%) of the proteins, and 131 possible npRNAs (including 58 antisense transcripts) were found. Almost 5000 annotated protein-coding genes were found to be disrupted in insertional mutant lines, which will accelerate future experimental validation of the annotations. The rice loci were determined by using cDNA sequences obtained from rice and other representative cereals. Our conservative estimate based on these loci and an extrapolation suggested that the gene number of rice is ~32,000, which is smaller than previous estimates. We conducted comparative analyses between rice and Arabidopsis thaliana and found that both genomes possessed several lineage-specific genes, which might account for the observed differences between these species, while they had similar sets of predicted functional domains among the protein sequences. A system to control translational efficiency seems to be conserved across large evolutionary distances. Moreover, the evolutionary process of protein-coding genes was examined. Our results suggest that natural selection may have played a role for duplicated genes in both species, so that duplication was suppressed or favored in a manner that depended on the function of a gene

Integrative Annotation of 21,037 Human Genes Validated by Full-Length cDNA Clones

The human genome sequence defines our inherent biological potential; the realization of the biology encoded therein requires knowledge of the function of each gene. Currently, our knowledge in this area is still limited. Several lines of investigation have been used to elucidate the structure and function of the genes in the human genome. Even so, gene prediction remains a difficult task, as the varieties of transcripts of a gene may vary to a great extent. We thus performed an exhaustive integrative characterization of 41,118 full-length cDNAs that capture the gene transcripts as complete functional cassettes, providing an unequivocal report of structural and functional diversity at the gene level. Our international collaboration has validated 21,037 human gene candidates by analysis of high-quality full-length cDNA clones through curation using unified criteria. This led to the identification of 5,155 new gene candidates. It also manifested the most reliable way to control the quality of the cDNA clones. We have developed a human gene database, called the H-Invitational Database (H-InvDB; http://www.h-invitational.jp/). It provides the following: integrative annotation of human genes, description of gene structures, details of novel alternative splicing isoforms, non-protein-coding RNAs, functional domains, subcellular localizations, metabolic pathways, predictions of protein three-dimensional structure, mapping of known single nucleotide polymorphisms (SNPs), identification of polymorphic microsatellite repeats within human genes, and comparative results with mouse full-length cDNAs. The H-InvDB analysis has shown that up to 4% of the human genome sequence (National Center for Biotechnology Information build 34 assembly) may contain misassembled or missing regions. We found that 6.5% of the human gene candidates (1,377 loci) did not have a good protein-coding open reading frame, of which 296 loci are strong candidates for non-protein-coding RNA genes. In addition, among 72,027 uniquely mapped SNPs and insertions/deletions localized within human genes, 13,215 nonsynonymous SNPs, 315 nonsense SNPs, and 452 indels occurred in coding regions. Together with 25 polymorphic microsatellite repeats present in coding regions, they may alter protein structure, causing phenotypic effects or resulting in disease. The H-InvDB platform represents a substantial contribution to resources needed for the exploration of human biology and pathology

Integrative annotation of 21,037 human genes validated by full-length cDNA clones.

publication en ligne. Article dans revue scientifique avec comité de lecture. nationale.National audienceThe human genome sequence defines our inherent biological potential; the realization of the biology encoded therein requires knowledge of the function of each gene. Currently, our knowledge in this area is still limited. Several lines of investigation have been used to elucidate the structure and function of the genes in the human genome. Even so, gene prediction remains a difficult task, as the varieties of transcripts of a gene may vary to a great extent. We thus performed an exhaustive integrative characterization of 41,118 full-length cDNAs that capture the gene transcripts as complete functional cassettes, providing an unequivocal report of structural and functional diversity at the gene level. Our international collaboration has validated 21,037 human gene candidates by analysis of high-quality full-length cDNA clones through curation using unified criteria. This led to the identification of 5,155 new gene candidates. It also manifested the most reliable way to control the quality of the cDNA clones. We have developed a human gene database, called the H-Invitational Database (H-InvDB; http://www.h-invitational.jp/). It provides the following: integrative annotation of human genes, description of gene structures, details of novel alternative splicing isoforms, non-protein-coding RNAs, functional domains, subcellular localizations, metabolic pathways, predictions of protein three-dimensional structure, mapping of known single nucleotide polymorphisms (SNPs), identification of polymorphic microsatellite repeats within human genes, and comparative results with mouse full-length cDNAs. The H-InvDB analysis has shown that up to 4% of the human genome sequence (National Center for Biotechnology Information build 34 assembly) may contain misassembled or missing regions. We found that 6.5% of the human gene candidates (1,377 loci) did not have a good protein-coding open reading frame, of which 296 loci are strong candidates for non-protein-coding RNA genes. In addition, among 72,027 uniquely mapped SNPs and insertions/deletions localized within human genes, 13,215 nonsynonymous SNPs, 315 nonsense SNPs, and 452 indels occurred in coding regions. Together with 25 polymorphic microsatellite repeats present in coding regions, they may alter protein structure, causing phenotypic effects or resulting in disease. The H-InvDB platform represents a substantial contribution to resources needed for the exploration of human biology and pathology

Development of Refrigeration Oil for Use With R32

R410A, which has a high GWP (global warming potential) of roughly 2000, is widely used in refrigeration systems today. Various low GWP alternative refrigerants have been investigated as part of the effort to stop global warming. One such refrigerant, R32, offers an alternative that improves system performance without the need for significant changes to current systems. Moreover, its GWP is roughly 1/3 that of R410A. R32 is thus a very promising candidate to replace R410A. However, current refrigeration oils designed for use with R410A have poor miscibility with R32. In this paper, we report on solutions to the miscibility problem and the characteristics of refrigeration oils for R32 systems

Development of miscibility improved oil for R32

R32 has been widely applied as an air-conditioner refrigerant. It is known that R32 is inferior to other refrigerants such as HFC and HFO in the miscibility with refrigeration oils. In addition, when R32　dissolves in refrigeration oils, the kinematic viscosity of the oils reduces remarkably. So it is difficult to improve the miscibility of refrigeration oil while suppressing the kinematic viscosity decrease of the oil when R32 dissolves in. Various investigations have revealed that the formulation of a new base material in POE improves the miscibility with R32 without decreasing the kinematic viscosity of the oil when R32 dissolves in. By using this technology, we have developed new refrigerating oils whose phase separation temperatures were -20 degree C or less under R32 atmosphere. In addition, the kinematic viscosities of the new oils when R32 dissolves in were equal to or greater than those of POE currently used for R410A.These new refrigerating oils are expected to be developed in a large model in which oil returnability is important in a refrigeration system. In this study, we will report the method and various characteristics under HFOs