474 research outputs found

    Triolein-based polycation lipid nanocarrier for efficient gene delivery: characteristics and mechanism

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    We proposed to develop a polycation lipid nanocarrier (PLN) with higher transfection efficiency than our previously described polycation nanostrucutred lipid nanocarrier (PNLC). PLN was composed of triolein, cetylated low-molecular-weight polyethylenimine, and dioleoyl phosphatidylethanolamine. The physicochemical properties of PLN and the PLN/DNA complexes (PDC) were characterized. The in vitro transfection was performed in human lung adenocarcinoma (SPC-A1) cells, and the intracellular mechanism was investigated as well. The measurements indicated that PLN and PDC are homogenous nanometer-sized particles with a positive charge. The transfection efficiency of PDC significantly increased with the content of triolein and was higher than that of PNLC and commercial Lipofectamine™ 2000. In particular, the transfection of PLN in the presence of 10% serum was more effective than that in its absence. With the help of specific inhibitors of chlorpromazine and filipin, the clathrin-dependent endocytosis pathway was determined to be the main contributor to the successful transfection mediated by PLN in SPC-A1 cells. The captured images verified that the fluorescent PDC was localized in the lysosomes and nuclei after endocytosis. Thus, PLN represents a novel efficient nonviral gene delivery vector

    Multiwavelength Analysis of a Nearby Heavily Obscured AGN in NGC 449

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    We presented the multiwavelength analysis of a heavily obscured active galactic nucleus (AGN) in NGC 449. We first constructed a broadband X-ray spectrum using the latest NuSTAR and XMM-Newton data. Its column density (1024cm2\simeq 10^{24} \rm{cm}^{-2}) and photon index (Γ2.4\Gamma\simeq 2.4) were reliably obtained by analyzing the broadband X-ray spectrum. However, the scattering fraction and the intrinsic X-ray luminosity could not be well constrained. Combined with the information obtained from the mid-infrared (mid-IR) spectrum and spectral energy distribution (SED) fitting, we derived its intrinsic X-ray luminosity (8.54×1042 erg s1\simeq 8.54\times 10^{42} \ \rm{erg\ s}^{-1}) and scattering fraction (fscat0.26%f_{\rm{scat}}\simeq 0.26\%). In addition, we also derived the following results: (1). The mass accretion rate of central AGN is about 2.54×102M yr12.54 \times 10^{-2} \rm{M}_\odot\ \rm{yr}^{-1}, and the Eddington ratio is 8.39×1028.39\times 10^{-2}; (2). The torus of this AGN has a high gas-to-dust ratio (NH/AV=8.40×1022 cm2 mag1N_{\rm H}/A_{\rm V}=8.40\times 10^{22}\ \rm{cm}^{-2}\ \rm{mag}^{-1}); (3). The host galaxy and the central AGN are both in the early stage of co-evolution.Comment: 12 pages, 5 figures, 3 tables, Accepted to PAS

    Electric power network fractal and its relationship with power system fault

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    Mreža elektro-energetskog sustava ima karakteristike fraktala. Ima osnovnu značajku složene mreže: sličnost samoj sebi. Autori su najprije izračunali vrijednosti fraktalne dimenzije za nekoliko elektro-energetskih rešetki, uključujući sustav 9 sabirnica WSCC (Western Systems Coordinating Council), sustav 14 sabirnica IEEE, sustav 30 sabirnica IEEE, sustav 39 sabirnica IEEE, sustav 118 sabirnica IEEE i sustav 300 sabirnica IEEE, kao i nekoliko stvarnih energetskih rešetki kao što su 500 kV glavne China Southern Power Grid (CSPG), 500 kV glavne energetske rešetke provincije Guangdong te 500 kV i 220 kV miješane energetske rešetke provincije Guangdong, itd. Na temelju fraktalne vrijednosti energetske rešetke analizirana je usporedba i odnos između fraktalne vrijednosti i intenziteta kvarenja energetskog sustava. Osnovni je zaključak da će za isti nivo napona, što je veća skala, energetska rešetka vjerojatno imati veću fraktalnu vrijednost i veći intenzitet kvarenja. Kod iste skale, što je gušća energetska rešetka to će vjerojatno biti veća fraktalna vrijednost i veći intenzitet kvarenja rešetke. Zaključci pružaju novi uvid u prosudbu statusa osjetljivosti energetskog sustava s interdisciplinarnog gledišta te voditi do novih smjerova u istraživanju.Electric power system network is with fractal characteristic. It has the basic feature of a complex network: self-similarity. The authors first calculated the fractal dimension values for several electric power grids, including WSCC (Western Systems Coordinating Council) 9 bus system, IEEE14 bus system, IEEE 30 bus system, IEEE 39 bus system, IEEE 118 bus system and IEEE 300 bus system; as well as some real power grids such as China Southern Power Grid (CSPG) 500 kV main power grid, Guangdong province 500 kV main power grid, and Guangdong province 500 kV and 220 kV mixed power grid, etc. Based on the power grid fractal value, a comparison and relationship between the fractal value and power system failure rate is analysed. The basic conclusion is that for the same voltage level, the larger the scale is, the larger fractal value and higher failure rate the power grid will possibly have. For the same scale, the denser the power grid, the larger fractal value and higher failure rate the power grid will probably have. The conclusions provide a new vision on the power system vulnerability status judgment from an interdisciplinary view and lead to a new research direction

    White Matter Abnormalities in Major Depression: A Tract-Based Spatial Statistics and Rumination Study

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    Increasing evidence indicates that major depressive disorder (MDD) is usually accompanied by altered white matter in the prefrontal cortex, the parietal lobe and the limbic system. As a behavioral abnormity of MDD, rumination has been believed to be a substantial indicator of the mental state of the depressive state. So far, however, no report that we are aware of has evaluated the relationship between white matter alterations and the ruminative state. In this study, we first explored the altered white matter using a tract-based spatial statistics (TBSS) method based on diffusion tensor imaging of 19 healthy and 16 depressive subjects. We then investigated correlations between the altered white matter microstructure in the identified altered regions and the severity of ruminations measured by the ruminative response scale. Our results demonstrated altered white matter microstructure in circuits connecting the prefrontal lobe, the parietal lobe and the limbic system (p<0.005, uncorrected), findings which support previous research. More importantly, the result also indicated that a greater alteration in the white matter is associated with a more ruminative state (p<0.05, Bonferroni corrected). The detected abnormalities in the white matter should be interpreted cautiously because of the small sample size in this study. This finding supports the psychometric significance of white matter deficits in MDD

    A Significantly High Abundance of “Candidatus Liberibacter asiaticus” in Citrus Fruit Pith: in planta Transcriptome and Anatomical Analyses

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    Huanglongbing, a highly destructive disease of citrus, is associated with the non-culturable phloem-limited α-proteobacterium “Candidatus Liberibacter asiaticus” (CLas). The distribution patterns of CLas in infected plant are variable and not consistent, which make the CLas detection and characterization more challenging. Here, we performed a systemic analysis of CLas distribution in citrus branches and fruits of 14 cultivars. A significantly high concentration of CLas was detected in fruit pith (dorsal vascular bundle) of 14 citrus cultivars collected at fruit maturity season. A 2-year monitoring assay of CLas population in citrus branches of “Shatangju” mandarin (Citrus reticulata Blanco “Shatangju”) revealed that CLas population already exhibited a high level even before the appearance of visual symptoms in the fruit rind. Quantitative analyses of CLas in serial 1.5-cm segments of fruit piths showed the CLas was unevenly distributed within fruit pith and tended to colonize in the middle or distal (stylar end) regions of pith. The use of CLas-abundant fruit pith for dual RNA-seq generated higher-resolution CLas transcriptome data compared with the leaf samples. CLas genes involved in transport system, flagellar assembly, lipopolysaccharide biosynthesis, virulence, stress response, and cell surface structure, as well as host genes involved in biosynthesis of antimicrobial-associated secondary metabolites, was up-regulated in leaf midribs compared with fruit pith. In addition, CLas infection caused the severe collapse in phloem and callose deposition in the plasmodesmata of fruit pith. The ability of fruit pith to support multiplication of CLas to high levels makes it an ideal host tissue for morphological studies and in planta transcriptome analyses of CLas–host interactions