A perfect code in a graph
Γ
is a subset
C
of
V
(
Γ
)
such that no two vertices in
C
are adjacent and every vertex in
V
(
Γ
)
\
C
is adjacent to exactly one vertex in
C
. Let
G
be a finite group and
C
...a subset of
G
. Then
C
is said to be a perfect code of
G
if there exists a Cayley graph of
G
admiting
C
as a perfect code. It is proved that a subgroup
H
of
G
is a perfect code of
G
if and only if a Sylow 2-subgroup of
H
is a perfect code of
G
. This result provides a way to simplify the study of subgroup perfect codes of general groups to the study of subgroup perfect codes of 2-groups. As an application, a criterion for determining subgroup perfect codes of projective special linear groups
PSL
(
2
,
q
)
is given.
Microplastics are generally considered as an emerging contaminant in the environment due to their toxic additives and transport of other contaminants. However, the potential threats of microplastics ...in soil should be concerned due to inconsistent research results. In this study, a meta-analysis based on 32 recent relevant studies was conducted to compare the response of soil system parameters including microbial community, aggregate structure, soil nutrient contents, and crop growth to the presence of microplastics. The results showed that microplastics presented no significant effects on soil dissolved organic carbon contents and the amounts of available phosphate, nitrate, and ammonium. Although microplastics would not significantly influence the diversity of soil microorganisms, they could significantly increase soil microorganism amounts with a standard mean difference at 19.32. We also found that microplastics tended to significantly decrease soil water stable macro-aggregate (> 0.25 mm) contents with a significantly negative standard mean difference (− 0.90) in meta-analysis. Moreover, soil microplastics seemed not to affect crop growth by having non-significant effects on both crop under-ground and above-ground biomasses. These results indicate that up to date, the main negative impacts caused by microplastics on soil systems could be their negative functions on soil aggregation.
Photocatalysis can be an effective technique for eliminating organic contaminants from water. In this study, BiOBr flower-spheres coupled with porous graphite carbon nitride (g-C3N4) were synthesized ...by controlling the dosage of cetyltrimethylammonium bromide (CTAB). Various characterization techniques were then applied to elucidate the structure-performance relationships of the resulting heterojunction photocatalysts in degrading organic dyes. Experimental results established an optimal molar ratio for KBr to CTAB of 5:1. Benefiting from a remarkable porous structure and tight coupling between porous g-C3N4 and BiOBr, the optimal BiOBr-g-C3N4(2%) exhibited enhanced visible light absorption capability and promoted the separation of photoinduced carriers. Total removal efficiency for rhodamine B (RhB, 25.0 mL, 20.0 mg L−1) reached 87% within 30 min in the presence of BiOBr-g-C3N4(2%) (20.0 mg) (i.e., 1.51 μmol (gphotocatalyst min)−1), which is superior to the performance of BiOBr (72%) (i.e., 1.25 μmol (gphotocatalyst min)−1), g-C3N4 (21%) (i.e., 0.37 μmol (gphotocatalyst min)−1). Furthermore, the photocatalytic reaction rate constant over the optimal heterojunction was 0.034 min−1, which is significantly larger than those of porous g-C3N4 (0.003 min−1) and BiOBr (0.015 min−1). Moreover, this type II heterojunction showed good universality for other organic dyes (such as methyl violet, methylene blue, and crystal violet), highlighting a promising potential role in the elimination of environmental pollutants.
•BiOBr flower spheres are assembled with urea-derived porous g-C3N4 nanosheets.•The II-type heterojunction structure effectively promotes the charge separation.•BiOBr-g-C3N4(2%) displays excellent elimination performance for many organic dyes.
On the 4-Flow Nullity of Graphs Deng, Feng; Zhang, Junyang
Bulletin of the Malaysian Mathematical Sciences Society,
09/2023, Letnik:
46, Številka:
5
Journal Article
Recenzirano
The
k
-flow nullity
n
k
(
G
)
of a graph
G
is the minimum number
n
for which
G
admits a
k
-flow
(
D
,
ψ
)
such that there are exactly
n
edges
e
with
ψ
(
e
)
=
0
. Let
X
and
Y
be two subgraphs of
G
. ...It is proved that
n
4
(
X
∪
Y
)
≤
n
4
(
X
)
+
n
4
(
Y
)
if
|
E
(
X
)
∩
E
(
Y
)
|
=
4
and the subgraph of
G
induced by
E
(
X
)
∩
E
(
Y
)
is a connected graph which is not a tree with 2 or 3 leaves.
Mechanically flexible optoelectronic devices and systems can enable a much broader range of applications than what their rigid counterparts can do, especially for novel bio-integrated optoelectronic ...systems, flexible consumer electronics and wearable sensors. Inorganic semiconductor could be a good candidate for the flexible PD when it can keep its high performance under the bending condition. Here, we demonstrate a III-V material-based flexible photodetector operating wavelength from 640 to 1700 nm with the high detectivity of 5.18 × 10
cm‧Hz
/W and fast response speed @1550 nm by using a simply top-to-down fabrication process. The optoelectrical performances are stable as the PDs are exposed to bending cycles with a radius of 15 mm up to 1000 times. Furthermore, the mechanical failure mode of the PD is also investigated, which suggests that the cracking and delamination failure mode are dominant in bending up and bending down direction, respectively. Such a flexible III-V material-based PD and design with stable and high performance could be a promising strategy for the application of the flexible broad spectrum detection.
Based on an experiment in Japan in 2008, this paper explores a new dimension of thinking. This paper introduces a variant form of public goods game, that is, ten participants compete for awards. It ...uses experimentation to consider behavioral and personality aspects, enabling us to explore new areas. In terms of behavior, awareness within and between groups is effective rather than a climate of non cooperation. In the aspect of personality, this paper studies the game from four aspects: preference for competition, preference for risk, enthusiasm for profit and trust in others. In a word, in a collective: the more people think about themselves, the less cooperative they are, and in most cases, they will not make profits; the more people who consider the collective, the more likely they are to cooperate, and in most cases, the higher their profits.
Draw textured yarn (DTY) packages is a significant raw material in manufacturing. Various defects will be generated on surface during production and transportation, of which hairiness is the most ...common and intractable defect. Many methods have been applied for fabric surface defect detection, but little research is aimed at DTY packages hairiness defects. In order to achieve the accuracy of DTY packages hairiness detection in industrial production, a method based on multi-directional anisotropic Gaussian directional derivatives was proposed to accomplish the DTY packages hairiness defect detection. Firstly, the original defect images were obtained by a device consisting of plane array light source, camera, and computer with image processing algorithm. Secondly, the gradient information of DTY packages images was constructed by anisotropic Gaussian directional derivative to characterize the defect. Then image response maps with all directions were fused to obtain the final response map. After that, a special difference of median (DOM) filter was proposed to remove useless information. Finally, the segmentation result was obtained by threshold method and morphological processing. Compared with various classical methods, the proposed method obtained the best performance in our evaluation experiments about DTY packages hairiness detection.
Cytidine and uridine are endogenous metabolites in the pyrimidine metabolism pathway, and cytidine is a substrate that can be metabolized into uridine via cytidine deaminase. Uridine has been widely ...reported to be effective in regulating lipid metabolism. However, whether cytidine could ameliorate lipid metabolism disorder has not yet been investigated. In this research, ob/ob mice were used, and the effect of cytidine (0.4 mg/mL in drinking water for five weeks) on lipid metabolism disorder was evaluated in terms of an oral glucose tolerance test, serum lipid levels, liver histopathological analysis and gut microbiome analysis. Uridine was used as a positive control. Our findings reveal that cytidine could alleviate certain aspects of dyslipidemia and improve hepatic steatosis via modulating the gut microbiota composition in ob/ob mice, especially increasing the abundance of short-chain fatty acids-producing microbiota. These results suggest that cytidine supplementation could be a potential therapeutic approach for dyslipidemia.
Understanding the distribution and development patterns of mining-induced fissures is crucial for environmental protection and geological hazard prevention. To address labor-intensive manual ...inspection, an automated approach leveraging Convolutional Neural Networks (CNNs) and Unmanned Aerial System Photogrammetry (UASP) is proposed for fissure identification and mapping. Initially, the ResNet-50 network was employed for the binary classification of the cropped UASP orthophoto images. A comparative analysis was conducted to determine the optimal model between DeepLabv3+ and U-Net. Subsequently, the identified fissures were mosaicked and spatially projected onto the original orthophoto image, incorporating precise projection data, thereby furnishing a spatial reference for environmental governance. The results indicate a classification accuracy of 93% for the ResNet-50 model, with the U-Net model demonstrating a superior identification performance. Fissure orientation and distribution patterns are influenced by the mining direction, ground position of the mining workface, and topographic undulations. Enhancing the CNN performance can be achieved by incorporating variables such as slope indices, vegetation density, and mining workface locations. Lastly, a remote unmanned approach is proposed for the automated mapping of mining-induced fissures, integrated with UAS automated charging station technology. This study contributes to the advancement of intelligent, labor-saving, and unmanned management approaches advocated by the mining industry, with potential for broad applications in mining environmental protection efforts.
Abstract
For the excellent drug delivery systems, advanced functional materials are indispensable. In recent years, mesoporous materials have shown a promising prospect and attracted much attention ...in the field of drug delivery. The research of mesoporous materials as drug carriers becomes to be a hot-spots. As a drug vehicle, it is favored by scientists due to the advantages in increasing drug dissolution and bioavailability, improving drug stability, sustained and controlled drug release, reducing drug side effects, good biocompatibility, targeting and so on. The anticipated
in vivo
performance for the mesoporous materials based drug delivery systems can be improved through optimizing the synthesis conditions or modifying the materials. In the paper, mesoporous silica nanoparticles (MSNs), mesoporous carbon nanoparticles (MCNs), organic frameworks (OFs), mesoporous hydroxyapatite (mHAp) are selected as the representative mesoporous materials. The structural characteristics, preparation methods, application in the field of drug delivery of above materials are reviewed, and the future research is prospected.
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