A simple strategy for the preparation of composites with high dielectric constant and thermal conductivity was developed through a typical interface design. Graphite nanoplatelets (GNPs) with a ...thickness of 20–50nm are fabricated and homogeneously dispersed in the epoxy matrix. A high dielectric constant of more than 230 and a high thermal conductivity of 0.54W/mK (a 157% increase over that of pure epoxy) could be obtained for the composites with a lower filler content of 1.892vol.%. The dielectric constant still remains at more than 100 even in the frequency range of 105–106Hz. When loaded at 2.703vol.%, GNP/epoxy composites have a dielectric constant higher than 140 in the frequency range of 102–104Hz and a high thermal conductivity of 0.72W/mK, which is a 240% increase over that of pure epoxy. The high dielectric constant and low loss tangent are observed in the composite with the GNPs content of 0.949vol.% around 104Hz. It is believed that high aspect ratio of GNPs and oxygen functional groups on their basal planes are critical issues of the constitution of a special interface region between the GNPs and epoxy matrix and the high performance of the composites.
Yellow rust, caused by Puccinia striiformis f. sp. tritici (Pst), is a devastating fungal disease threatening much of global wheat production. Race-specific resistance (R)-genes are used to control ...rust diseases, but the rapid emergence of virulent Pst races has prompted the search for a more durable resistance. Here, we report the cloning of Yr15, a broad-spectrum R-gene derived from wild emmer wheat, which encodes a putative kinase-pseudokinase protein, designated as wheat tandem kinase 1, comprising a unique R-gene structure in wheat. The existence of a similar gene architecture in 92 putative proteins across the plant kingdom, including the barley RPG1 and a candidate for Ug8, suggests that they are members of a distinct family of plant proteins, termed here tandem kinase-pseudokinases (TKPs). The presence of kinase-pseudokinase structure in both plant TKPs and the animal Janus kinases sheds light on the molecular evolution of immune responses across these two kingdoms.
6:2 Chlorinated polyfluoroalkyl ether sulfonate (F-53B) is a new type of perfluorinated and polyfluoroalkyl substance (PFAS) that is used extensively in industry and manufacturing. F-53B causes ...damage to multiple mammalian organs. However, the impacts of F-53B on bone are unknown. Maternal exposure to F-53B is of particular concern because of the vulnerability of the developing fetus and newborn to contaminants from the mother. The goal of this study was to examine the impacts of maternal F-53B exposure on bone growth and development in offspring and to explore its underlying mechanisms. Herein, C57BL/6 J mice were given free access to deionized water containing 0, 0.57, or 5.7 mg/L F-53B during pregnancy and lactation. F-53B exposure resulted in impaired liver function, decreased IGF-1 secretion, dysregulation of bone metabolism and disruption of the dynamic balance between osteoblasts and osteoclasts in male offspring. F-53B inhibits longitudinal bone growth and development and causes osteoporosis in male offspring. F-53B may affect the growth and development of offspring bone via the IGF-1/OPG/RANKL/CTSK signaling pathway. This study provides new insights for the study of short stature and bone injury caused by F-53B.
•Maternal F-53B exposure inhibits bone growth and development in male offspring.•Maternal F-53B exposure causes osteoporosis in male offspring.•This demonstrates that F-53B may be genotoxic.•F-53B may cause bone damage via the IGF-1/OPG/RANKL/CTSK signaling pathway.
Stereocomplex-polylactic acid (SC-PLA) is obtained in poly(d-lactic) acid/poly(l-lactic) acid (PDLA/PLLA) blends under adjusting processing conditions. It is found that the degree of crystallinity of ...overall SC-PLA is up to 43.7% in PDLA/PLLA blends of 1:1 mass ratio. Formation of stereocomplex (SC) crystals forces molecular chains in the blends to be more closely arranged and further enhances interaction between molecular chains, thus forming a physical cross-linking network in the SC crystals, resulting in the blends having a special microstructure. The mechanism of formation of the SC crystal physical cross-linking network is elucidated by dielectric spectroscopy, and the relationships between homocomplex (HC) crystals, SC crystals, and amorphous regions in the blends are also analyzed. Interestingly, mechanical properties of the blends are significantly improved due to formation of an SC crystal cross-linking network.
On the eccentric distance sum of graphs Ilić, Aleksandar; Yu, Guihai; Feng, Lihua
Journal of mathematical analysis and applications,
09/2011, Volume:
381, Issue:
2
Journal Article
Peer reviewed
Open access
The eccentric distance sum is a novel topological index that offers a vast potential for structure activity/property relationships. For a graph
G, it is defined as
ξ
d
(
G
)
=
∑
v
∈
V
ε
(
v
)
D
(
v
)
..., where
ε
(
v
)
is the eccentricity of the vertex
v and
D
(
v
)
=
∑
u
∈
V
(
G
)
d
(
u
,
v
)
is the sum of all distances from the vertex
v. Motivated by G. Yu, L. Feng, A. Ilić, On the eccentric distance sum of trees and unicyclic graphs, J. Math. Anal. Appl. 375 (2011) 934–944, in this paper we characterize the extremal trees and graphs with maximal eccentric distance sum. Various lower and upper bounds for the eccentric distance sum in terms of other graph invariants including the Wiener index, the degree distance, eccentric connectivity index, independence number, connectivity, matching number, chromatic number and clique number are established. In addition, we present explicit formulae for the values of eccentric distance sum for the Cartesian product, applied to some graphs of chemical interest (like nanotubes and nanotori).
In this paper, we present sharp bounds for the Zagreb indices, Harary index and hyper-Wiener index of graphs with a given matching number, and we also completely determine the extremal graphs.
The genetic bottlenecks associated with plant domestication and subsequent selection in man-made agroecosystems have limited the genetic diversity of modern crops and increased their vulnerability to ...environmental stresses. Wild emmer wheat, the tetraploid progenitor of domesticated wheat, distributed along a wide range of ecogeographical conditions in the Fertile Crescent, has valuable "left behind" adaptive diversity to multiple diseases and environmental stresses. The biotic and abiotic stress responses are conferred by series of genes and quantitative trait loci (QTLs) that control complex resistance pathways. The study of genetic diversity, genomic organization, expression profiles, protein structure and function of biotic and abiotic stress-resistance genes, and QTLs could shed light on the evolutionary history and adaptation mechanisms of wild emmer populations for their natural habitats. The continuous evolution and adaptation of wild emmer to the changing environment provide novel solutions that can contribute to safeguarding food for the rapidly growing human population.
Let
G be a simple connected graph with the vertex set
V
(
G
)
. The eccentric distance sum of
G is defined as
ξ
d
(
G
)
=
∑
v
∈
V
(
G
)
ε
(
v
)
D
G
(
v
)
, where
ε
(
v
)
is the eccentricity of the ...vertex
v and
D
G
(
v
)
=
∑
u
∈
V
(
G
)
d
(
u
,
v
)
is the sum of all distances from the vertex
v. In this paper we characterize the extremal unicyclic graphs among
n-vertex unicyclic graphs with given girth having the minimal and second minimal eccentric distance sum. In addition, we characterize the extremal trees with given diameter and minimal eccentric distance sum.
This paper investigates the interplay between the algebraic properties of the rings, the combinatorial properties of their corresponding zero-divisor graphs, and the associated Hermitian matrix of ...such graphs. For a finite ring
R
, its zero-divisor graph may contain both directed edges and undirected edges; such graphs are called mixed graphs. The Hermitian matrices of mixed graphs are natural generalizations of the adjacency matrices of undirected graphs. In this paper, we completely determine the structure and the Hermitian eigenvalues of the zero-divisor graph
Γ
(
D
×
R
)
by using the structure and the Hermitian eigenvalues of the zero-divisor graph
Γ
(
R
)
. As applications, we investigate
Γ
(
D
×
R
)
for some special
R
and extend some known results on this topic.
In this paper, we consider the spectral radius of signless
p
-Laplacian of a graph, which is a generalization of the quadratic form of the signless Laplacian matrix for
p
=
2
. Let
π
=
(
d
0
,
d
1
,
...…
,
d
n
-
1
)
be a non-increasing sequence of positive integers and
G
π
the set of graphs with degree sequence
π
. In this paper, we obtain some transformations for graphs in
G
π
that do not decrease the largest signless
p
-Laplacian eigenvalue of a graph. Furthermore, if
∑
i
=
0
n
-
1
d
i
=
2
n
and
d
2
≥
2
, then we identify the graph maximizing the signless
p
-Laplacian spectral radius among
G
π
. As an application, we get the extremal graph maximizing the signless
p
-Laplacian spectral radius among all unicyclic graphs.
PDF
