Supergravity Analysis of Hybrid Inflation Model from D3--D7 System

The slow-roll inflation is a beautiful paradigm, yet the inflaton potential can hardly be sufficiently flat when unknown gravitational effects are taken into account. However, the hybrid inflation models constructed in D = 4 N = 1 supergravity can be consistent with N = 2 supersymmetry, and can be naturally embedded into string theory. This article discusses the gravitational effects carefully in the string model, using D = 4 supergravity description. We adopt the D3--D7 system of Type IIB string theory compactified on K3 x T^2/Z_2 orientifold for definiteness. It turns out that the slow-roll parameter can be sufficiently small despite the non-minimal Kahler potential of the model. The conditions for this to happen are clarified in terms of string vacua. We also find that the geometry obtained by blowing up singularity, which is necessary for the positive vacuum energy, is stabilized by introducing certain 3-form fluxes.Comment: 21 pages; v3. a typo corrected, and some changes made in sections 4.1 and 4.2, accordingl

Rheology of SiO2/(Acrylic Polymer/Epoxy) Suspensions. I. Linear Viscoelasticity

Linear viscoelastic properties of SiO2/(AP/EP) suspension with various SiO2 volume fractions (φ) in a blend of acrylic polymer (AP) and epoxy (EP) were investigated at various temperatures (T). The AP/EP contained 70 vol% of EP. The SiO2 particles were treated with epoxy silane coupling agent. The effects of the SiO2 particles are more pronounced in the terminal zone: a transition from viscoelastic liquid (φ ≤ 30 vol %) to viscoelastic solid (φ ≥ 40 vol %) was observed which can be interpreted as a critical gelation occurring at a critical particle content and critical gel temperature. The SiO2/(AP/EP) systems exhibited a critical gel behavior at φ ≅ 35 vol % and T ≅ 100 °C characterized with a power-law relationship between the storage and loss moduli (G′ and G″) and frequency (ω); G′ = G″/tan(nπ/2) ∝ ωn. The critical gel exponent (n) was estimated to be about 0.45. The gelation occurred with increasing T

On the thermodynamic stability and structural transition of clathrate hydrates

Gas mixtures of methane and ethane form structure II clathrate hydrates despite the fact that each of pure methane and pure ethane gases forms the structure I hydrate. Optimization of the interaction potential parameters for methane and ethane is attempted so as to reproduce the dissociation pressures of each simple hydrate containing either methane or ethane alone. An account for the structural transitions between type I and type II hydrates upon changing the mole fraction of the gas mixture is given on the basis of the van der Waals and Platteeuw theory with these optimized potentials. Cage occupancies of the two kinds of hydrates are also calculated as functions of the mole fraction at the dissociation pressure and at a fixed pressure well above the dissociation pressure

Modeling membrane morphological change during autophagosome formation

Autophagy is an intracellular degradation process that is mediated by de novo formation of autophagosomes. Autophagosome formation involves dynamic morphological changes; a disk-shaped membrane cisterna grows, bends to become a cup-shaped structure, and finally develops into a spherical autophagosome. We have constructed a theoretical model that integrates the membrane morphological change and entropic partitioning of putative curvature generators, which we have used to investigate the autophagosome formation process quantitatively. We show that the membrane curvature and the distribution of the curvature generators stabilize disk- and cup-shaped intermediate structures during autophagosome formation, which is quantitatively consistent with in vivo observations. These results suggest that various autophagy proteins with membrane curvature-sensing properties control morphological change by stabilizing these intermediate structures. Our model provides a framework for understanding autophagosome formation.Comment: 33 pages, 8 figure

Influence of brain-derived neurotrophic factor on pathfinding of dentate granule cell axons, the hippocampal mossy fibers

Mossy fibers, the dentate granule cell axons, are generated throughout an animal's lifetime. Mossy fiber paths and synapses are primarily restricted to the stratum lucidum within the CA3 region. Brain-derived neurotrophic factor (BDNF), a neurotrophin family protein that activates Trk neurotrophin receptors, is highly expressed in the stratum lucidum in an activity-dependent manner. The addition of a Trk neurotrophin receptor inhibitor, K252a, to cultured hippocampal slices induced aberrant extension of mossy fibers into ectopic regions. BDNF overexpression in granule cells ameliorated the mossy fiber pathway abnormalities caused by a submaximal dose of K252a. A similar rescue was observed when BDNF was expressed in CA3 pyramidal cells, most notably in mossy fibers distal to the expression site. These findings are the first to clarify the role of BDNF in mossy fiber pathfinding, not as an attractant cue but as a regulator, possibly acting in a paracrine manner. This effect of BDNF may be as a signal for new fibers to fasciculate and extend further to form synapses with neurons that are far from active BDNF-expressing synapses. This mechanism would ensure the emergence of new independent dentate gyrus-CA3 circuits by the axons of new-born granule cells

Exploring autistic-like traits relating to empathic attitude and psychological distress in hospital pharmacists

BACKGROUND: Pharmacists are expected to play a key role in modern cancer care. Research suggests that an empathic approach and attitude in medical staff improves the quality of patient care. An empathic attitude and psychological distress are thought to be associated with autistic-like traits, but little is known about such traits. OBJECTIVE: In this study, we aimed to clarify the associations among autistic-like traits, empathic attitude in a medical context, and psychological health in hospital pharmacists. SETTING: Eligibility criteria for inclusion were certified pharmacists working at hospitals for patient care who returned their questionnaires. METHOD: Eight hundred and twenty-three hospital pharmacists completed a number of self-administered questionnaires anonymously by mail. MAIN OUTCOME MEASURES: Scores were obtained on the Autism-Spectrum Quotient, the Jefferson Scale of Empathy, the General Health Questionnaire-12, and subscales of the Interpersonal Reactivity Index (Perspective Taking, IRI-Empathic Concern, IRIPersonal Distress). We performed correlation and mediation analyses to confirm that the empathy and general health questionnaires were associated with autism-spectrum quotient scores, and with each IRI subscale. RESULTS: Complete responses were obtained from 379 pharmacists comprising 151 males (39.8 %) with a mean age of 37.7 ± 10.8 years (missing data, n = 13) and a median of 11 years after qualification as a pharmacist. Autism-Spectrum Quotient scores were inversely correlated with empathy (r = -0.22, p < 0.001) and positively correlated with general health scores (r = 0.40, p < 0.001). In the models with mediation, the inverse correlation between autism-spectrum quotient and empathy scores was mediated indirectly by IRI-Perspective Taking and IRI-Empathic Concern, and the positive correlation between autism-spectrum quotient and general health was mediated indirectly by IRI-Personal Distress. There were also direct effects, with significant effects of autism-spectrum quotient on empathy and general health scores. CONCLUSION: Our findings suggest that autistic-like traits affect both empathic attitude in a medical context and the psychological health of pharmacists. We recommend that to improve empathy in those with high levels of autistic-like traits, we may need to develop specialized interventions, such as improving communication skills training