3,450 research outputs found
Nuclear matter properties with nucleon-nucleon forces up to fifth order in the chiral expansion
The properties of nuclear matter are studied using state-of-the-art
nucleon-nucleon forces up to fifth order in chiral effective field theory. The
equations of state of symmetric nuclear matter and pure neutron matter are
calculated in the framework of the Brueckner-Hartree-Fock theory. We discuss in
detail the convergence pattern of the chiral expansion and the regulator
dependence of the calculated equations of state and provide an estimation of
the truncation uncertainty. For all employed values of the regulator, the
fifth-order chiral two-nucleon potential is found to generate nuclear
saturation properties similar to the available phenomenological high precision
potentials. We also extract the symmetry energy of nuclear matter, which is
shown to be quite robust with respect to the chiral order and the value of the
regulator.Comment: 10 pages, 3 figures, 3 table
Birkhoff's Theorem in f(T) Gravity up to the Perturbative Order
f(T) gravity, a generally modified teleparallel gravity, has become very
popular in recent times as it is able to reproduce the unification of inflation
and late-time acceleration without the need of a dark energy component or an
inflation field. In this present work, we investigate specifically the range of
validity of Birkhoff's theorem with the general tetrad field via perturbative
approach. At zero order, Birkhoff's theorem is valid and the solution is the
well known Schwarzschild-(A)dS metric. Then considering the special case of the
diagonal tetrad field, we present a new spherically symmetric solution in the
frame of f(T) gravity up to the perturbative order. The results with the
diagonal tetrad field satisfy the physical equivalence between the Jordan and
the so-called Einstein frames, which are realized via conformal transformation,
at least up to the first perturbative order.Comment: 8 pages, no figure. Final version, accepted for publication in EPJ
Sequence-dependent abnormal aggregation of human Tau fragment in an inducible cell model
AbstractA pathological hallmark of Alzheimer disease (AD) is the accumulation of misfolded hyperphosphorylated microtubule-associated protein Tau within neurons, forming neurofibrillary tangles and leading to synaptic dysfunction and neuronal death. Here we study sequence-dependent abnormal aggregation of human fragment Tau244–372 in an inducible cell model. As evidenced by confocal laser scanning microscopy, Western blot, and immunogold electron microscopy, fibril-forming motifs are essential and sufficient for abnormal aggregation of Tau244–372 in SH-SY5Y neuroblastoma cells induced by Congo red: when its two fibril-forming segments PHF6 and PHF6* are deleted, Tau244–372 does lose its ability to form fibrils in SH-SY5Y cells, and the replacement of PHF6 and PHF6* with an unrelated amyloidogenic sequence IFQINS from human lysozyme does rescue the fibril-forming ability of Tau244–372 in SH-SY5Y cells. By contrast, insertion of a non-fibril forming peptide GGGGGG does not drive the disabled Tau244–372 to misfold in SH-SY5Y cells. Furthermore, as revealed by quantum dots based probes combined with annexin V staining, annexin V-FITC apoptosis detection assay, and immunofluorescence, fibril-forming motifs are essential and sufficient for early apoptosis of living SH-SY5Y cells induced by abnormal aggregation of Tau244–372. Our results suggest that fibril-forming motifs could be the determinants of Tau protein tending to misfold in living cells, thereby inducing neuronal apoptosis and causing the initiation and development of AD
Extended Birkhoff's Theorem in the f(T) Gravity
The f(T) theory, a generally modified teleparallel gravity, has been proposed
as an alternative gravity model to account for the dark energy phenomena.
Following our previous work [Xin-he Meng and Ying-bin Wang, EPJC(2011),
arXiv:1107.0629v1], we prove that the Birkhoff's theorem holds in a more
general context, specifically with the off diagonal tetrad case, in this
communication letter. Then, we discuss respectively the results of the external
vacuum and internal gravitational field in the f(T) gravity framework, as well
as the extended meaning of this theorem. We also investigate the validity of
the Birkhoff's theorem in the frame of f(T) gravity via conformal
transformation by regarding the Brans-Dicke-like scalar as effective matter,
and study the equivalence between both Einstein frame and Jordan frame.Comment: 7 pages, 1 figure, submitted to EPJ-C. arXiv admin note: substantial
text overlap with arXiv:1107.062
Effect of Vacuum Pre-cooling on the Circulation and Shelf Quality of Postharvest Baby Cabbage
To optimize the treatment conditions for vacuum pre-cooling of baby cabbage and maintain the fresh quality of postharvest baby cabbage, a central composite response surface experiment with two factors and three levels was conducted on the basis of analyzing the effects of different vacuum pre-cooling final temperature (0, 2 and 4 ℃) and different vacuum pre-cooling final pressure (400, 600, 800 and 1000 Pa) on the pre-cooling of postharvest baby cabbage. The results showed that compared with the control without pre-cooling and the pre-cooling group with final temperature of 0 ℃, the pre-cooling with final temperature of 2~4 ℃ at the final pressure of 600 Pa could better maintain the appearance quality of postharvest baby cabbage, inhibit the increase of respiratory rate and malondialdehyde (MDA) content. Under the condition of final temperature of 2 ℃, compared with the control without pre-cooling and the pre-cooling group with a final pressure of 1000 Pa, pre-cooling with final pressures of 400~800 Pa could also better maintain the appearance quality of postharvest baby cabbage, inhibit the increase of respiratory rate and MDA content. Further central composite response surface experiments showed that the optimal conditions for vacuum pre-cooling of postharvest baby vegetables were final temperature of 4.0 ℃ and final pressure of 600 Pa. The vacuum pre-cooling condition not only maintained good quality of postharvest baby vegetable, but also increased the content of soluble protein, total phenols, and ascorbic acid by 18.78%, 18.47% and 33.23%, respectively. Therefore, appropriate vacuum pre-cooling treatment is a highly potential commercialization technology that could effectively maintain the good quality of postharvest baby vegetable during circulation and shelf life
Genome-wide analysis and characterization of Dendrocalamus farinosus SUT gene family reveal DfSUT4 involvement in sucrose transportation in plants
Sucrose is the main transported form of photosynthetic products. Sucrose transporter (SUT) participates in the translocation of sucrose from source to sink, which is important for the growth and development of plants. Dendrocalamus farinosus is an important economic crop in southwestern China because of its high growth rate, high fiber content, and dual usage for food and timber, but the mechanism of sucrose transportation in D. farinosus is unclear. In this study, a total of 12 SUT transporter genes were determined in D. farinosus by whole-genome identification. DfSUT2, DfSUT7, and DfSUT11 were homologs of rice OsSUT2, while DfSUT4 was a homolog of OsSUT4, and these four DfSUT genes were expressed in the leaf, internode, node, and bamboo shoots of D. farinosus. In addition, DfSUT family genes were involved in photosynthetic product distribution, ABA/MeJA responses, and drought resistance, especially DfSUT4. The function of DfSUT4 was then verified in Nicotiana tabacum. DfSUT4 was localized mainly in the leaf mesophyll and stem phloem of pDfSUT4::GUS transgenic plant. The overexpression of DfSUT4 gene in transgenic plant showed increases of photosynthetic rate, above-ground biomass, thousand grain weight, and cellulose content. Our findings altogether indicate that DfSUT4 can be a candidate gene that can be involved in phloem sucrose transportation from the source leaves to the sink organs, phytohormone responses, abiotic stress, and fiber formation in plants, which is very important in the genetic improvement of D. farinosus and other crops
Efficacy of combined traditional Chinese medicine spray with premature ejaculation desensitization therapy for the treatment of primary premature ejaculation
Objectives: We recommend a new kind of spray made from eight kinds of traditional Chinese medicine, we aimed to investigate the safety and clinical efficacy of combined traditional Chinese medicine spray (TCMS) with premature ejaculation desensitization therapy (PEDT) for the treatment of primary premature ejaculation (PPE).Methods: A total of 90 patients with PPE were randomly assigned to receive TCMS, PEDT monotherapy or TCMS plus PEDT combination therapy for 6 weeks. Intravaginal ejaculation latency time (IELT) and Chinese index of sexual function for premature ejaculation (CIPE-5) were measured to evaluate the effect of each treatment.Results: Eighty six (86) participants completed the study voluntarily. Both IELT and CIPE-5 in these three groups increased after treatment when compared with baseline levels (p< 0.01). IELT and CIPE-5 after treatment in TCMS plus PEDT group were significantly higher than those in the other two groups (both p <0.05). Additionally, clinical efficacy in TCMS plus PEDT group (89.7%) was significantly higher than in TCMS (65.5%) and PEDT group (67.9%) (p< 0.01).Conclusion: The self-made TCMS was safe and effective for the treatment of PPE, a combination of TCMS and PEDT therapy was more effective than the TCMS or PEDT monotherapy.Keywords: Primary premature ejaculation (PPE); traditional Chinese mdicine spray (TCMS); premature ejaculation desensitization training therapy (PEDT); Intravaginal ejaculation latency time (IELT); Chinese index of sexual function for premature ejaculation (CIPE-5
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