Bismuth(III)-Promoted Trifluoromethylthiolation of Pyrazolin-5-ones with Trifluoromethanesulfenamide

An efficient and facile method for the synthesis of trifluoromethylthiolated 5-hydroxy-1<i>H</i>-pyrazole derivatives by reaction of pyrazolin-5-ones with trifluoromethanesulfenamide (PhNHSCF₃) in the presence of BiCl₃ was developed

Revealing the promising near-room-temperature thermoelectric performance in Ag2Se single crystals

With high carrier mobility and intrinsic low lattice thermal conductivity, Ag2Se compounds have attracted increasing attention for thermoelectric application near room temperature. Due to its phase transition at ∼406 K and resulting thermal volume expansion, the growth and thermoelectric properties of large-sized Ag2Se single crystals have seldom been reported so far. In this work, the vertical Bridgeman method was used for growing bulk Ag2Se single crystal, with an orientation preference along low-symmetric (201) plane. The Hall mobility as high as 2 000 cm2/(V·s) and weak electron-phonon coupling contributes to a high electronic quality BE of ∼7.0 in near-room-temperature β-Ag2Se single crystals, which is superior to the high-temperature phase α-Ag2Se. The observed low lattice thermal conductivity of 0.8 W/(m·K) at 300 K is due to the low group speeds and strong anharmonicity. A promising peak zT of 0.66 at 375 K and an average zT of 0.65 at 300–375 K were realized in β-Ag2Se crystals. The low Vickers hardness and good ductile properties were confirmed by experiment and theoretical analysis. This work not only synthesized large-sized and highly-orientated Ag2Se crystals, but also revealed its great potential of thermoelectric performance and mechanical properties for various applications near room temperature

A resource selection optimization model for data grid

In order to meet data grids' data service reliability and transmission time constraints, and to take account of the network load and efficient use of node resources, a resource selection optimization model for data grid is presented. The model can give the optimal decision-making of the collection for participating nodes, and at the same time, set the weighting factor to balance network load and resource costs. A backup node transmission strategy is proposed to further enhance the usability of the model. The simulative experiments show that the model and the strategy are correct and effective

NaCl Promotes the Efficient Formation of Haematococcus pluvialis Nonmotile Cells under Phosphorus Deficiency

Natural astaxanthin helps reduce the negative effects caused by oxidative stress and other related factors, thereby minimizing oxidative damage. Therefore, it has considerable potential and broad application prospects in human health and animal nutrition. Haematococcus pluvialis is considered to be the most promising cell factory for the production of natural astaxanthin. Previous studies have confirmed that nonmotile cells of H. pluvialis are more tolerant to high intensity of light than motile cells. Cultivating nonmotile cells as the dominant cell type in the red stage can significantly increase the overall astaxanthin productivity. However, we know very little about how to induce nonmotile cell formation. In this work, we first investigated the effect of phosphorus deficiency on the formation of nonmotile cells of H. pluvialis, and then investigated the effect of NaCl on the formation of nonmotile cells under the conditions of phosphorus deficiency. The results showed that, after three days of treatment with 0.1% NaCl under phosphorus deficiency, more than 80% of motile cells had been transformed into nonmotile cells. The work provides the most efficient method for the cultivation of H. pluvialis nonmotile cells so far, and it significantly improves the production of H. pluvialis astaxanthin

Differences between Motile and Nonmotile Cells of Haematococcus pluvialis in the Production of Astaxanthin at Different Light Intensities

Haematococcus pluvialis, as the best natural resource of astaxanthin, is widely used in nutraceuticals, aquaculture, and cosmetic industries. The purpose of this work was to compare the differences in astaxanthin accumulation between motile and nonmotile cells of H. pluvialis and to determine the relationship between the two cells and astaxanthin production. The experiment design was achieved by two different types of H. pluvialis cell and three different light intensities for an eight day induction period. The astaxanthin concentrations in nonmotile cell cultures were significantly increased compared to motile cell cultures. The increase of astaxanthin was closely associated with the enlargement of cell size, and the nonmotile cells were more conducive to the formation of large astaxanthin-rich cysts than motile cells. The cyst enlargement and astaxanthin accumulation of H. pluvialis were both affected by light intensity, and a general trend was that the higher the light intensity, the larger the cysts formed, and the larger the quantity of astaxanthin accumulated. In addition, the relatively low cell mortality rate in the nonmotile cell cultures indicated that the nonmotile cells have a stronger tolerance to photooxidative stress. We suggest that applying nonmotile cells as the major cell type of H. pluvialis to the induction period may help to enhance the content of astaxanthin and the stability of astaxanthin production

Gene Expression Profiling in Human Fetal Liver and Identification of Tissue- and Developmental-Stage-Specific Genes through Compiled Expression Profiles and Efficient Cloning of Full-Length cDNAs

Fetal liver intriguingly consists of hepatic parenchymal cells and hematopoietic stem/progenitor cells. Human fetal liver aged 22 wk of gestation (HFL22w) corresponds to the turning point between immigration and emigration of the hematopoietic system. To gain further molecular insight into its developmental and functional characteristics, HFL22w was studied by generating expressed sequence tags (ESTs) and by analyzing the compiled expression profiles of liver at different developmental stages. A total of 13,077 ESTs were sequenced from a 3′-directed cDNA library of HFL22w, and classified as follows: 5819 (44.5%) matched to known genes; 5460 (41.8%) exhibited no significant homology to known genes; and the remaining 1798 (13.7%) were genomic sequences of unknown function, mitochondrial genomic sequences, or repetitive sequences. Integration of ESTs of known human genes generated a profile including 1660 genes that could be divided into 15 gene categories according to their functions. Genes related to general housekeeping, ESTs associated with hematopoiesis, and liver-specific genes were highly expressed. Genes for signal transduction and those associated with diseases, abnormalities, or transcription regulation were also noticeably active. By comparing the expression profiles, we identified six gene groups that were associated with different developmental stages of human fetal liver, tumorigenesis, different physiological functions of Itoh cells against the other types of hepatic cells, and fetal hematopoiesis. The gene expression profile therefore reflected the unique functional characteristics of HFL22w remarkably. Meanwhile, 110 full-length cDNAs of novel genes were cloned and sequenced. These novel genes might contribute to our understanding of the unique functional characteristics of the human fetal liver at 22 wk. [The sequence data described in this paper have been submitted to the GenBank data library under the accession nos. listed in Table 6 herein