First principles study of edge carboxylated graphene quantum dots

The structure stability and electronic properties of edge carboxylated hexagonal and triangular graphene quantum dots are investigated by using density functional theory. The calculated binding energies show that the hexagonal clusters with armchair edges have the highest stability among all other flakes. The binding energy of carboxylated graphene quantum dots increases by increasing the number of attached carboxyl groups. Our study shows that the total dipole moment significantly increases by adding COOH with the highest values observed in triangular clusters. The edge states in triangular graphene with zigzag edges produce completely different energy spectrum from other shapes as (a) the energy gap in triangular zigzag cluster is very small compared to other clusters and (b) the highest occupied molecular orbital is localized at the edges which is in contrast to other clusters where it is distributed over the cluster surface. The enhanced reactivity and the controllable energy gap by shape and edge termination make graphene quantum dots ideal nanodevices for various applications such as sensors. The infrared spectra for different flakes are presented for confirmation and detection of the obtained results

On a Generalization of a Theorem due to Larcombe on the Sum of a 3F2 Series

MSC 2010: 33C2

Image findings of cranial nerve pathology on [18F]-2- deoxy-D-glucose (FDG) positron emission tomography with computerized tomography (PET/CT): a pictorial essay.

This article aims to increase awareness about the utility of (18)F -FDG-PET/CT in the evaluation of cranial nerve (CN) pathology. We discuss the clinical implication of detecting perineural tumor spread, emphasize the primary and secondary (18)F -FDG-PET/CT findings of CN pathology, and illustrate the individual (18)F -FDG-PET/CT CN anatomy and pathology of 11 of the 12 CNs

Comments on "New hypergeometric identities arising from Gauss’s second summation theorem"

In 1997, Exton [J. Comput. Appl. Math. 88 (1997) 269–274] obtained a general transfor- mation involving hypergeometric functions by elementary manipulation of series. A number of hypergeometric identities not previously recorded in the literature were then deduced by application of Gauss’ second summation theorem and other known hypergeometric summa- tion theorems. However, many of the results stated by Exton contain errors. It is the purpose of this note to present the corrected forms of these hypergeometric identities

On the contiguous relations of hypergeometric series

AbstractContiguous relations are a fundamental concept within the theory of hypergeometric series and orthogonal polynomials. Their study goes back to Gauss who gave a list of 15 “fundamental” relations for the F12 hypergeometric series. In this paper we will prove some consequences of contiguous relations of F12

On an Extension of Kummer's Second Theorem

The aim of this paper is to establish an extension of Kummer's second theorem in the form   e-x/2F22[a,2+d;x2a+2,d;]=F10[-;x2/16a+3/2;]+((a/d-1/2)/(a+1))x F10[-;x2/16a+3/2;]+(cx2/2(2a+3))F10[-;x2/16a+5/2;], where  c=1/a+11/2-a/d+a/d(d+1),  d≠0,-1,-2,…. For d=2a, we recover Kummer's second theorem. The result is derived with the help of Kummer's second theorem and its contiguous results available in the literature. As an application, we obtain two general results for the terminating F23(2) series. The results derived in this paper are simple, interesting, and easily established and may be useful in physics, engineering, and applied mathematics

„Kitalált történetek”. ,A látogató’ és az ,Útvesztõ’

Andrographolide (Andro) has emerged recently as a potential and effective anticancer agent with induction of apoptosis in some cancer cell lines while induction of G2/M arrest with weak apoptosis in others. Few studies have proved that Andro is also effective in combination therapy. The flavonoid Taxifolin (Taxi) has showed anti-oxidant and antiproliferative effects against different cancer cells. Therefore, the present study investigated the cytotoxic effects of Andro alone or in combination with Taxi on HeLa cells. The combination of Andro with Taxi was synergistic at all tested concentrations and combination ratios. Andro alone induced caspase-dependent apoptosis which was enhanced by the combination with Taxi and attenuated partly by using Z-Vad-Fmk. Andro induced a protective reactive oxygen species (ROS)-dependent autophagy which was attenuated by Taxi. The activation of p53 was involved in Andro-induced autophagy where the use of Taxi or pifithrin-α (PFT-α) decreased it while the activation of JNK was involved in the cell death of HeLa cells but not in the induction of autophagy. The mitochondrial outer-membrane permeabilization (MOMP) plays an important role in Andro-induced cell death in HeLa cells. Andro alone increased the MOMP which was further increased in the case of combination. This led to the increase in AIF and cytochrome c release from mitochondria which consequently increased caspase-dependent and independent cell death. In conclusion, Andro induced a protective autophagy in HeLa cells which was reduced by Taxi and the cell death was increased by increasing the MOMP and subsequently the