Dark energy in hybrid inflation

The situation that a scalar field provides the source of the accelerated expansion of the universe while rolling down its potential is common in both the simple models of the primordial inflation and the quintessence-based dark energy models. Motivated by this point, we address the possibility of causing the current acceleration via the primordial inflation using a simple model based on hybrid inflation. We trigger the onset of the motion of the quintessence field via the transition field, and find that the fate of the universe depends on the true vacuum energy determined by choosing the parameters. We also briefly discuss the variation of the equation of state and the possible implementation of our scenario in supersymmetric theories.Comment: (v1) 10 pages, 1 figure; (v2) 12 pages, considerably revised, to appear in Physical Review

Sustainability of multi-field inflation and bound on string scale

We study the effects of the interaction terms between the inflaton fields on the inflationary dynamics in multi-field models. With power law type potential and interactions, the total number of e-folds may get considerably reduced and can lead to unacceptably short period of inflation. Also we point out that this can place a bound on the characteristic scale of the underlying theory such as string theory. Using a simple multi-field chaotic inflation model from string theory, the string scale is constrained to be larger than the scale of grand unified theory.Comment: (v1) 9 pages, 1 figure;(v2) 10 pages, references added; (v3) 15 pages, 4 figures, more discussions about parameters and observable quantities, references added, to appear in Modern Physics Letters

Sublingual Immunization with M2-Based Vaccine Induces Broad Protective Immunity against Influenza

The ectodomain of matrix protein 2 (M2e) of influenza A virus is a rationale target antigen candidate for the development of a universal vaccine against influenza as M2e undergoes little sequence variation amongst human influenza A strains. Vaccine-induced M2e-specific antibodies (Abs) have been shown to display significant cross-protective activity in animal models. M2e-based vaccine constructs have been shown to be more protective when administered by the intranasal (i.n.) route than after parenteral injection. However, i.n. administration of vaccines poses rare but serious safety issues associated with retrograde passage of inhaled antigens and adjuvants through the olfactory epithelium. In this study, we examined whether the sublingual (s.l.) route could serve as a safe and effective alternative mucosal delivery route for administering a prototype M2e-based vaccine. The mechanism whereby s.l. immunization with M2e vaccine candidate induces broad protection against infection with different influenza virus subtypes was explored.A recombinant M2 protein with three tandem copies of the M2e (3M2eC) was expressed in Escherichia coli. Parenteral immunizations of mice with 3M2eC induced high levels of M2e-specific serum Abs but failed to provide complete protection against lethal challenge with influenza virus. In contrast, s.l. immunization with 3M2eC was superior for inducing protection in mice. In the latter animals, protection was associated with specific Ab responses in the lungs.The results demonstrate that s.l. immunization with 3M2eC vaccine induced airway mucosal immune responses along with broad cross-protective immunity to influenza. These findings may contribute to the understanding of the M2-based vaccine approach to control epidemic and pandemic influenza infections

Management of mixed forest in Cambodia : A case study in Sandan district , Kampong Thom

Exploitation of forests without utilizing information on harvest potential has resulted in mismanagement and deforestation worldwide, particularly in Southeast Asia. The purpose of this report is to provide the comprehensive information on harvest potential of Cambodia's mixed forest, which can be used as a strong foundation for sound forest management in Cambodia.Analysis of 20 inventoried clusters showed that, on average, the stocking of Sandan's mixed forest was 695 trees/ha and 168 m3/ha for stand density and stand volume, respectively. Of 168 m3, dipterocarp, non-dipterocarp and unknowns shared 37%, 37% and 26%, respectively. On a selective felling of 30 years, Sandan's mixed forest can potentially provide 28 m3/ha or 8 trees/ha, of which dipterocarp species represents 40% of the trees to be harvested. This figure is more or less the same to those in Thailand and Vietnam. Sound forest management requires the proper zoning of the forest area to be harvested and to be set aside from harvesting. Research on vegetation and wood utilization of non-dipterocarp and unknown trees should be encouraged since the majority of local people still depend mainly on them for cooking energy, food, medicine and other customary uses. Strong and long-term political commitment to research is always required to ensure the long-term sustainability of natural resources as whole for the benefit of future generations.Article信州大学農学部紀要. 38(1-2): 45-54 (2002)journal articl

Noninvasive optical activation of Flp recombinase for genetic manipulation in deep mouse brain regions

Spatiotemporal control of gene expression or labeling is a valuable strategy for identifying functions of genes within complex neural circuits. Here, we develop a highly light-sensitive and efficient photoactivatable Flp recombinase (PA-Flp) that is suitable for genetic manipulation in vivo. The highly light-sensitive property of PA-Flp is ideal for activation in deep mouse brain regions by illumination with a noninvasive light-emitting diode. In addition, PA-Flp can be extended to the Cre-lox system through a viral vector as Flp-dependent Cre expression platform, thereby activating both Flp and Cre. Finally, we demonstrate that PA-Flp-dependent, Cre-mediated Ca(v)3.1 silencing in the medial septum increases object-exploration behavior in mice. Thus, PA-Flp is a noninvasive, highly efficient, and easy-to-use optogenetic module that offers a side-effect-free and expandable genetic manipulation tool for neuroscience research. © The Author(s) 2019.11Nsciescopu

Exciton Dissociation and Charge-Transport Enhancement in Organic Solar Cells with Quantum-Dot/N-doped CNT Hybrid Nanomaterials

The incorporation of InP quantum-dot/N-doped multiwalled carbon nanotube (QD:NCNT) nanohybrids in the active layer of poly(3-hexylthiophene)/indene-C-60 bisadduct (P3HT/ICBA) bulk-heterojuction solar cells enhances V-OC and J(SC). The QDs encourage exciton dissociation by promoting electron transfer, while the NCNTs enhance the transport of the separated electrons and eventual charge collection. Such a synergistic effect successfully improves the power conversion efficiency (PCE) from 4.68% (reference cells) to 6.11%.169721sciescopu