Warm-intermediate inflationary universe model in braneworld cosmologies

Warm-intermediate inflationary universe models in the context of braneworld cosmologies are studied. This study is done in the weak and strong dissipative regimes. We find that the scalar potentials and dissipation coefficients in terms of the scalar field evolve as type-power-law and powers of logarithms, respectively. General conditions required for these models to be realizable are derived and discussed. We also study the scalar and tensor perturbations for each regime. We use recent astronomical observations to constrain the parameters appearing in the braneworld models.     

On-Surface Synthesis and Characterization of Acene-Based Nanoribbons Incorporating Four-Membered Rings

A bottom up method for the synthesis of unique tetracene-based nanoribbons, which incorporate cyclobutadiene moieties as linkers between the acene segments, is reported. These structures were achieved through the formal [2+2] cycloaddition reaction of ortho-functionalized tetracene precursor monomers. The formation mechanism and the electronic and magnetic properties of these nanoribbons were comprehensively studied by means of a multitechnique approach. Ultra-high vacuum scanning tunneling microscopy showed the occurrence of metal-coordinated nanostructures at room temperature and their evolution into nanoribbons through formal [2+2] cycloaddition at 475 K. Frequency-shift non-contact atomic force microscopy images clearly proved the presence of bridging cyclobutadiene moieties upon covalent coupling of activated tetracene molecules. Insight into the electronic and vibrational properties of the so-formed ribbons was obtained by scanning tunneling microscopy, Raman spectroscopy, and theoretical calculations. Magnetic properties were addressed from a computational point of view, allowing us to propose promising candidates to magnetic acene-based ribbons incorporating four-membered rings. The reported findings will increase the understanding and availability of new graphene-based nanoribbons with high potential in future spintronics.     

Directing Group-Promoted Inert C−O Bond Activation Using Versatile Boronic Acid as a Coupling Agent

A simple Ni(cod)₂ and carbene mediated strategy facilitates the efficient catalytic cross-coupling of methoxyarenes with a variety of organoboron reagents. Directing groups facilitate the activation of inert C−O bonds in under-utilized aryl methyl ethers enabling their adaptation for C−C cross-coupling reactions as less toxic surrogates to the ubiquitous haloarenes. The method reported enables C−C cross-coupling with readily available and economical arylboronic acid reagents, which is unprecedented, and compares well with other organoboron reagents with similarly high reactivity. Extension to directing group assisted chemo-selective C−O bond cleavage, and further application towards the synthesis of novel bifunctionalized biaryls is reported. Key to the success of this protocol is the use of directing groups proximal to the reaction center to facilitate the activation of the inert C−OMe bond.     

Antibacterial activity of agave fructans against salmonella typhimurium

Abstract

The objective of this study was to evaluate the antimicrobial effect of Agave fructans against the Salmonella Typhimurium in “in vitro” experiments. The result of the antimicrobial activity was 263.89?±?0, 414.95?±?12.83, 494.54?±?13.88, 522.29?±?0, 580.41?±?14.92?AU for 10, 20, 30, 40 and 50% of Agave fructans (AF) respectively. In addition, there is a significant effect on the growth of the bacteria with all the percentages of AF evaluated (p?<?0.001, R2?=?0.859) with respect to the control. The growth rate of Salmonella with 25% AF was statistically significant compared to the control (?0.7353?±?0.586, 0.0079?±?0.002?D.O./h, respectively; p?>?0.01). Agave fructans could be an alternative to prevent the infections caused by Salmonella.     

Transcendental values of class group <Emphasis Type="Italic">L</Emphasis>-functions

Let K be an algebraic number field and f a complex-valued function on the ideal class group of K. Then, f extends in a natural way to the set of all non-zero ideals of the ring of integers of K and we can consider the Dirichlet series \({L(s,f) =\sum_{{\mathfrak a}} f({\mathfrak a}){\bf N}({\mathfrak a})^{-s}}\) which converges for \({{\mathfrak R}(s) >1 }\). After extending this function to \({{\mathfrak R}(s)=1}\), and in the case that f does not contain the trivial character, we study the special value L(1, f) when f is algebraic valued and K is an imaginary quadratic field. Applying Kronecker’s limit formula and Baker’s theory of linear forms in logarithms, we derive a variety of results related to the transcendence of this special value.     

Strongly nonlinear variational inequalities and generalized pseudocontractions

The solvability of a class of generalized strongly nonlinear variational inequality problems on nonempty closed convex sets in Hilbert spaces is presented.     

EPR of Cu2+-doped tris-sarcosine calcium chloride

The EPR study of the Cu²⁺-doped tris-sarcosine calcium chloride (TSCC) at room temperature is reported. Two magnetically inequivalent sites for Cu²⁺ were observed. The rhombic spin Hamiltonian parameters are determined by fitting the EPR spectra for two centres: Cu²⁺(I) g₁ = 2.0276, g₂ = 2.0517, g₃ = 2.4019, A₁ = 82, A₂ = 128, A₃ = 152 [G] and Cu²⁺(II) g₁ = 2.0231, g₂ = 2.0368, g₃ = 2.5294, A₁ = 76, A₂ = 92, A₃ = 156 [G]. The ground state wave function is also determined. The g-anisotropy is evaluated and compared with the experimental value. Further, the optical study of the crystal at room temperature is carried out and the nature of bonding in the complex is discussed.     

Multiobjective routing problems

Summary Many network routing problems, particularly where the transportation of hazardous materials is involved, are multiobjective in nature; that is, it is desired to optimise not only physical path length but other features as well. Several such problems are defined here and a general framework for multiobjective routing problems is proposed. The notion of “efficient solution” is defined and it is demonstrated, by means of an example, that a problem may have very many solutions which are efficient. Next, potentially useful solution methods for multiobjective routing problems are discussed with emphasis being placed on the use of shortest/k-shortest path techniques. Finally, some directions for possible further research are indicated. Invited by B. Pelegrin     

Magnetization transfer and T2 quantitation in normal appearing cortical gray matter and white matter adjacent to focal abnormality in patients with traumatic brain injury

Traumatic brain injury (TBI) is one of the commonest causes of morbidity and mortality in the developed countries with posttraumatic epilepsy and functional disability being its major sequelae. The purpose of this study was to test the hypothesis whether the normal appearing adjacent gray and white matter regions on T2 and T1 weighted magnetization transfer (MT) weighted images show any abnormality on quantitative imaging in patients with TBI. A total of 51 patients with TBI and 10 normal subjects were included in this study. There were significant differences in T2 and MT ratio values of T2 weighted and T1 weighted MT normal appearing gray matter regions adjacent to focal image abnormality compared to normal gray matter regions in the normal individuals as corresponding contralateral regions of the TBI patient's group (p < 0.05). However the adjoining normal appearing white matter quantitative values did not show any significant change compared to the corresponding contralateral normal white matter values. We conclude that quantitative T2 and MT ratio values provide additional abnormality in patients with TBI that is not discernable on conventional T2 weighted and T1 weighted MT imaging especially in gray matter. This additional information may be of value in overall management of these patients with TBI.