10 research outputs found
Spectral radius, fractional -factor and ID-factor-critical graphs
Let be a graph and be a function. For any two
positive integers and with , a fractional -factor of
with the indicator function is a spanning subgraph with vertex set
and edge set such that for
any vertex , where and E_{G}(v)=\{e\in
E(G)| e~\mbox{is incident with}~v~\mbox{in}~G\}. A graph is
ID-factor-critical if for every independent set of whose size has the
same parity as , has a perfect matching. In this paper, we
present a tight sufficient condition based on the spectral radius for a graph
to contain a fractional -factor, which extends the result of Wei and
Zhang [Discrete Math. 346 (2023) 113269]. Furthermore, we also prove a tight
sufficient condition in terms of the spectral radius for a graph with minimum
degree to be ID-factor-critical.Comment: 14 pages, 2 figure
Spectral radius and spanning trees of graphs
For integer a spanning -ended-tree is a spanning tree with at
most leaves. Motivated by the closure theorem of Broersma and Tuinstra
[Independence trees and Hamilton cycles, J. Graph Theory 29 (1998) 227--237],
we provide tight spectral conditions to guarantee the existence of a spanning
-ended-tree in a connected graph of order with extremal graphs being
characterized. Moreover, by adopting Kaneko's theorem [Spanning trees with
constraints on the leaf degree, Discrete Appl. Math. 115 (2001) 73--76], we
also present tight spectral conditions for the existence of a spanning tree
with leaf degree at most in a connected graph of order with extremal
graphs being determined, where is an integer
An improvement of sufficient condition for -leaf-connected graphs
For integer a graph is called -leaf-connected if and given any subset with always has a
spanning tree such that is precisely the set of leaves of Thus a
graph is -leaf-connected if and only if it is Hamilton-connected. In this
paper, we present a best possible condition based upon the size to guarantee a
graph to be -leaf-connected, which not only improves the results of Gurgel
and Wakabayashi [On -leaf-connected graphs, J. Combin. Theory Ser. B 41
(1986) 1-16] and Ao, Liu, Yuan and Li [Improved sufficient conditions for
-leaf-connected graphs, Discrete Appl. Math. 314 (2022) 17-30], but also
extends the result of Xu, Zhai and Wang [An improvement of spectral conditions
for Hamilton-connected graphs, Linear Multilinear Algebra, 2021]. Our key
approach is showing that an -closed non--leaf-connected graph must
contain a large clique if its size is large enough. As applications, sufficient
conditions for a graph to be -leaf-connected in terms of the (signless
Laplacian) spectral radius of or its complement are also presented.Comment: 15 pages, 2 figure
Exploring research hotspots and future directions in neural tube defects field by bibliometric and bioinformatics analysis
BackgroundNeural tube defects (NTDs) is the most common birth defect of the central nervous system (CNS) which causes the death of almost 88,000 people every year around the world. Much efforts have been made to investigate the reasons that contribute to NTD and explore new ways to for prevention. We trawl the past decade (2013â2022) published records in order to get a worldwide view about NTDs research field.Methods7,437 records about NTDs were retrieved from the Web of Science (WOS) database. Tools such as shell scripts, VOSviewer, SCImago Graphica, CiteSpace and PubTator were used for data analysis and visualization.ResultsOver the past decade, the number of publications has maintained an upward trend, except for 2022. The United States is the country with the highest number of publications and also with the closest collaboration with other countries. Baylor College of Medicine has the closest collaboration with other institutions worldwide and also was the most prolific institution. In the field of NTDs, research focuses on molecular mechanisms such as genes and signaling pathways related to folate metabolism, neurogenic diseases caused by neural tube closure disorders such as myelomeningocele and spina bifida, and prevention and treatment such as folate supplementation and surgical procedures. Most NTDs related genes are related to development, cell projection parts, and molecular binding. These genes are mainly concentrated in cancer, Wnt, MAPK, PI3K-Akt and other signaling pathways. The distribution of NTDs related SNPs on chromosomes 1, 3, 5, 11, 14, and 17 are relatively concentrated, which may be associated with high-risk of NTDs.ConclusionBibliometric analysis of the literature on NTDs field provided the current status, hotspots and future directions to some extant. Further bioinformatics analysis expanded our understanding of NTDs-related genes function and revealed some important SNP clusters and loci. This study provided some guidance for further studies. More extensive cooperation and further research are needed to overcome the ongoing challenge in pathogenesis, prevention and treatment of NTDs
Table_1_Exploring research hotspots and future directions in neural tube defects field by bibliometric and bioinformatics analysis.XLSX
BackgroundNeural tube defects (NTDs) is the most common birth defect of the central nervous system (CNS) which causes the death of almost 88,000 people every year around the world. Much efforts have been made to investigate the reasons that contribute to NTD and explore new ways to for prevention. We trawl the past decade (2013â2022) published records in order to get a worldwide view about NTDs research field.Methods7,437 records about NTDs were retrieved from the Web of Science (WOS) database. Tools such as shell scripts, VOSviewer, SCImago Graphica, CiteSpace and PubTator were used for data analysis and visualization.ResultsOver the past decade, the number of publications has maintained an upward trend, except for 2022. The United States is the country with the highest number of publications and also with the closest collaboration with other countries. Baylor College of Medicine has the closest collaboration with other institutions worldwide and also was the most prolific institution. In the field of NTDs, research focuses on molecular mechanisms such as genes and signaling pathways related to folate metabolism, neurogenic diseases caused by neural tube closure disorders such as myelomeningocele and spina bifida, and prevention and treatment such as folate supplementation and surgical procedures. Most NTDs related genes are related to development, cell projection parts, and molecular binding. These genes are mainly concentrated in cancer, Wnt, MAPK, PI3K-Akt and other signaling pathways. The distribution of NTDs related SNPs on chromosomes 1, 3, 5, 11, 14, and 17 are relatively concentrated, which may be associated with high-risk of NTDs.ConclusionBibliometric analysis of the literature on NTDs field provided the current status, hotspots and future directions to some extant. Further bioinformatics analysis expanded our understanding of NTDs-related genes function and revealed some important SNP clusters and loci. This study provided some guidance for further studies. More extensive cooperation and further research are needed to overcome the ongoing challenge in pathogenesis, prevention and treatment of NTDs.</p
Comparative transcriptome profiling analysis provides insight into the mechanisms for sugar change in Chinese jujube (Ziziphus jujuba Mill.) under rainâproof cultivation
Abstract Chinese jujube (Ziziphus jujuba Mill.) is a globally popular and economically important fruit that is rich in bioactive compounds with strong antiâcancer effects. Rainâproof cultivation is widely used to cultivate Chinese jujube, as it helps avoid rainfall damage during fruit harvest. Although the sugar content of jujube fruits differs between rainâproof and openâfield cultivation, the underlying molecular mechanisms are unknown. Here, we analyzed the levels of sugar content, sugar accumulation pattern, and transcriptome profiles of jujube fruits at five developmental stages grown under rainâproof and openâfield cultivation modes. The sugar content of jujube fruits was significantly higher under rainâproof cultivation than under openâfield cultivation, although the sugar composition and sugar accumulation patterns were comparable. Comparative analysis of transcriptomic profiles showed that rainâproof cultivation enhanced the intrinsic metabolic activity of fruit development. Gene expression and correlation analyses suggested that ZjSPS, ZjSS, ZjHXK, and ZjINV regulate the developmentârelated changes in sugar content in jujube fruits grown under rainâproof cultivation. Temperature, humidity, and moisture conditions were key climatic factors affecting sugar accumulation. Our results provide insights into the molecular mechanisms regulating sugar content and sugar accumulation in Chinese jujube fruits grown under rainâproof cultivation, and we provide genetic resources for studying the development mechanism of Chinese jujube fruit
The Roles of Morphology on the Relaxation Rates of Magnetic Nanoparticles
The shape of magnetic nanoparticles
is of great importance in determining
their contrast abilities for magnetic resonance imaging. Various magnetic
nanoparticles have been developed to achieve high <i>T</i><sub>1</sub> or <i>T</i><sub>2</sub> relaxivities, but
the mechanism on how morphology influences the water proton relaxation
process is still unrevealed. Herein we synthesize manganese-doped
iron oxide (MnIO) nanoparticles of the same volume with six different
shapes and reveal the relationship between morphologies and <i>T</i><sub>1</sub>/<i>T</i><sub>2</sub> relaxation
rates. The morphology of magnetic nanoparticles largely determines
the effective radius and the gradient of stray field, which in turn
affects the transverse relaxation rate. The longitudinal relaxivity
has positive correlation with the surface-area-to-volume ratio and
the occupancy rate of effective metal ions on exposed surfaces of
magnetic nanoparticles. These findings together with the summary of <i>r</i><sub>2</sub>/<i>r</i><sub>1</sub> ratios could
help to guide the screening for the optimal shapes of promising <i>T</i><sub>1</sub> or <i>T</i><sub>2</sub> contrast
agents. Varying effective radii could be utilized to change negative
contrast abilities. The surface-area-to-volume ratio and the amount
of effective metal ions on exposed surface are instrumental for tuning
positive contrast abilities. These principles could serve as guidelines
for design and development of high-performance nanoparticle-based
contrast agents
Melatonin alleviates valproic acid-induced neural tube defects by modulating Src/PI3K/ERK signaling and oxidative stress
Neural tube defects (NTDs) represent a developmental disorder of the nervous system that can lead to significant disability in children and impose substantial social burdens. Valproic acid (VPA), a widely prescribed first-line antiepileptic drug for epilepsy and various neurological conditions, has been associated with a 4-fold increase in the risk of NTDs when used during pregnancy. Consequently, urgent efforts are required to identify innovative prevention and treatment approaches for VPA-induced NTDs. Studies have demonstrated that the disruption in the delicate balance between cell proliferation and apoptosis is a crucial factor contributing to NTDs induced by VPA. Encouragingly, our current data reveal that melatonin (MT) significantly inhibits apoptosis while promoting the restoration of neuroepithelial cell proliferation impaired by VPA. Moreover, further investigations demonstrate that MT substantially reduces the incidence of neural tube malformations resulted from VPA exposure, primarily by suppressing apoptosis through the modulation of intracellular reactive oxygen species levels. In addition, the Src/PI3K/ERK signaling pathway appears to play a pivotal role in VPA-induced NTDs, with significant inhibition observed in the affected samples. Notably, MT treatment successfully reinstates Src/PI3K/ERK signaling, thereby offering a potential underlying mechanism for the protective effects of MT against VPA-induced NTDs. In summary, our current study substantiates the considerable protective potential of MT in mitigating VPA-triggered NTDs, thereby offering valuable strategies for the clinical management of VPA-related birth defects